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Sample records for outer voring plateau

  1. Crustal rheological strength heterogeneities control the formation of continental plateau margins

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Zhu, Bojing; Yang, Xiaolin

    2015-08-01

    The margins bordering the Tibetan Plateau show two end-member morphologies in topographic gradient: steep margins and low-gradient margins. To investigate the formation mechanism of convergent intracontinental plateau margins, we conduct 2D numerical experiments to simulate crustal deformation process across plateau margins. Our numerical experiments demonstrate that heterogeneities in crustal rheological strength control significantly the formation of plateau margins when subjected to crustal convergence. A very steep margin is the result of crustal convergence between plateau with weak lower crust and foreland basin with strong lower crust. By contrast, a low-gradient margin could result from crustal convergence between plateau and foreland with less strength contrast. This finding suggests that the diversity in topographic gradient along the Tibetan Plateau borders reflects heterogeneities in crustal rheological strength across the plateau margins. Steep gradient at the margins indicate large crustal rheological strength contrasts between the weak ductile lower crust of the Tibetan Plateau and its strong surrounding foreland basins, like the Sichuan Basin, the Tarim Basin and the Qaidam Basin. Beneath these steep margins the horizontal flow of the Tibetan ductile lower crust is inhibited and forced to extrude to support escarpments. Low-gradient at the margins indicate less crustal strength variations between the plateau and outer forelands, like at the northeastern and southeastern margins, where they might be outlets for the weak ductile Tibetan lower crust to flow away from the plateau.

  2. CENTRAL PLATEAU REMEDIATION

    SciTech Connect

    ROMINE, L.D.

    2006-02-01

    A systematic approach to closure planning is being implemented at the Hanford Site's Central Plateau to help achieve the goal of closure by the year 2035. The overall objective of Central Plateau remediation is to protect human health and the environment from the significant quantity of contaminated material that resulted from decades of plutonium production in support of the nation's defense. This goal will be achieved either by removing contaminants or placing the residual contaminated materials in a secure configuration that minimizes further migration to the groundwater and reduces the potential for inadvertent intrusion into contaminated sites. The approach to Central Plateau cleanup used three key concepts--closure zones, closure elements, and closure process steps--to create an organized picture of actions required to complete remediation. These actions were merged with logic ties, constraints, and required resources to produce an integrated time-phased schedule and cost profile for Central Plateau closure. Programmatic risks associated with implementation of Central Plateau closure were identified and analyzed. Actions to mitigate the most significant risks are underway while high priority remediation projects continue to make progress.

  3. Radiative plateau inflation

    NASA Astrophysics Data System (ADS)

    Ballesteros, Guillermo; Tamarit, Carlos

    2016-02-01

    We describe how monomial chaotic inflation becomes compatible with the latest CMB data thanks to radiative corrections producing a plateau. The interactions of the inflaton with other fields, required for reheating, can flatten the potential and moderate the production of primordial gravitational waves, keeping these below the current upper bound. We show that the appearance of a plateau requires that the inflaton couples to fermions and to another scalar or a gauge group. We give concrete examples of minimal particle physics models leading to plateaus for quadratic and quartic chaotic inflation. We also provide a three-parameter model-independent description of radiatively corrected inflation that is amenable to CMB analyses.

  4. Methanotroph outer membrane preparation.

    PubMed

    Karlsen, Odd A; Berven, Frode S; Jensen, Harald B; Fjellbirkeland, Anne

    2011-01-01

    All presently known methanotrophs are gram-negative bacteria suggesting that they are surrounded by a two-layered membrane: an inner or cytoplasmic membrane and an outer membrane. In the methanotroph Methylococcus capsulatus (Bath), separation of the two membranes has allowed studies on protein and lipid composition of the outer membrane. Its outer membrane can be isolated from purified cell envelopes by selective solubilization of the inner membranes with the detergent Triton X-100. The proteins associated with the outer membrane can further be fractionated into integral and tightly associated proteins and peripheral loosely associated proteins. We present here protocols for this fractionation and show how the proteins associated with the outer leaflet of the outer membrane can be isolated and identified by whole-cell biotin surface labeling. PMID:21419921

  5. The Outer Limits: English.

    ERIC Educational Resources Information Center

    Tyler, Barbara R.; Biesekerski, Joan

    The Quinmester course "The Outer Limits" involves an exploration of unknown worlds, mental and physical, through fiction and nonfiction. Its purpose is to focus attention on the ongoing conquest of the frontiers of the mind, the physical world, and outer space. The subject matter includes identification and investigation of unknown worlds in the…

  6. Outer planet satellites

    SciTech Connect

    Schenk, P.M. )

    1991-01-01

    Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon. 210 refs.

  7. Understanding Career Plateauing: Implications for Counseling.

    ERIC Educational Resources Information Center

    Tan, Carol S.; Salomone, Paul R.

    1994-01-01

    Defines career plateauing, explains types and sources of plateauing, and suggests counseling interventions to assist individuals to recognize and adjust to plateauing. Recommends proactive measures to perpetuate work motivation of effective plateaued workers and to remediate work behavior of ineffective, plateaued workers. Includes 19 citations.…

  8. Outer Planet Flagship Mission

    NASA Astrophysics Data System (ADS)

    Cutts, James; Niebur, C.; Dudzinski, L.; Coradini, M.; Lebreton, J.

    2008-09-01

    Studies for Outer Planet Missions have been ongoing for many years, but in 2007 NASA commissioned four specific studies to be considered for further examination; the Europa Explorer, Titan Explorer, Enceladus Mission and Jupiter Science Orbiter. During the same time frame ESA invited Outer Planet proposals under the Cosmic Vision call. Two were submitted, TandEm and LaPlace, which focused on Titan/Enceladus and Jupiter System science respectively. In 2008, NASA selected two of the missions, Europa Explorer and Titan Explorer, and ESA selected the two outer planet proposals for further study. This poster describes the process by which NASA and ESA are collaborating on the current studies which are now named the Titan/Saturn (TSSM) and Europa/Jupiter Missions (EJSM). We provide an update on the background, organization and schedule for these two mission studies.

  9. Outer Planet Flagship Missions

    NASA Astrophysics Data System (ADS)

    Niebur, C.; Dudzinski, L.; Coradini, M.; Lebreton, J.; Cutts, J. A.

    2008-05-01

    Studies for Outer Planet Missions have been ongoing for many years, but in 2007 NASA commissioned four specific studies to be considered for further examination; the Europa Explorer, Titan Explorer, Enceladus Mission and Jupiter Science Orbiter. During the same time frame ESA invited Outer Planet proposals under the Cosmic Vision call. Two were submitted, TandEM and LaPlace, which focused on Titan/Enceladus and Jupiter System science respectively. In 2008, NASA selected two of the missions, Europa Explorer and Titan Explorer, and ESA selected the two outer planet proposals for further study. This poster describes the process by which NASA and ESA are collaborating on the current studies which are now named the Titan/Saturn and Europa/Jupiter Missions. We provide the background, organization and schedule that are presently envisaged for these two mission studies.

  10. Outer Planets Flagship Mission

    NASA Astrophysics Data System (ADS)

    Niebur, C.; Dudzinski, L.; Coradini, M.; Lebreton, J. P.; Cutts, J. A.

    2008-09-01

    Studies for Outer Planet Missions have been ongoing for many years, but in 2007 NASA commissioned four specific studies to be considered for further examination; the Europa Explorer, Titan Explorer, Enceladus Mission and Jupiter Science Orbiter. During the same time frame ESA invited Outer Planet proposals under the Cosmic Vision call. Two were submitted, TandEm and LaPlace, which focused on Titan/Enceladus and Jupiter System science respectively. In 2008, NASA selected two of the missions, Europa Explorer and Titan Explorer, and ESA selected the two outer planet proposals for further study. This poster describes the process by which NASA and ESA are collaborating on the current studies which are now named the Titan/Saturn (TSSM) and Europa/Jupiter Missions (EJSM). We provide an update on the background, organization and schedule for these two mission studies.

  11. Saturn's outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Schardt, A. W.; Behannon, K. W.; Carbary, J. F.; Eviatar, A.; Lepping, R. P.; Siscoe, G. L.

    1983-01-01

    Similarities between the Saturnian and terrestrial outer magnetosphere are examined. Saturn, like Earth, has a fully developed magnetic tail, 80 to 100 RS in diameter. One major difference between the two outer magnetospheres is the hydrogen and nitrogen torus produced by Titan. This plasma is, in general, convected in the corotation direction at nearly the rigid corotation speed. Energies of magnetospheric particles extend to above 500 keV. In contrast, interplanetary protons and ions above 2 MeV have free access to the outer magnetosphere to distances well below the Stormer cutoff. This access presumably occurs through the magnetotail. In addition to the H+, H2+, and H3+ ions primarily of local origin, energetic He, C, N, and O ions are found with solar composition. Their flux can be substantially enhanced over that of interplanetary ions at energies of 0.2 to 0.4 MeV/nuc.

  12. Outer membrane protein purification.

    PubMed

    Arigita, C; Jiskoot, W; Graaf, M R; Kersten, G F

    2001-01-01

    The major outer membrane proteins (OMPs) from Neisseria meningitidis, which are expressed at high levels, are subdivided in five classes based on molecular weight (1,2) (see Table 1). Table 1 Major Meningococcal Outer-Membrane Proteins Outer-membrane proteins Name Molecular maass Function/characteristics Class 1 PorA 44-47 kDa Porin Class 2/3 PorB 37-42 kDa Porin Class 4 Rmp Reductionmodifiableprotein, unknown Class 5 Opa 26-30 kDa Adhesion,opacity protein Opc 25 kDa Invasion, opacity protein Iron-regulated proteins Mirp 37 kDa Iron acquisition (?);majoriron-regulatedprotein FrpB 70 kDa Ferric enterobactin receptor (also FetA) Adapted from ref. (1). PMID:21336748

  13. Law in Outer Space.

    ERIC Educational Resources Information Center

    Schmidt, William G.

    1997-01-01

    Provides an overview of the current practice and fascinating future of legal issues involved in outer space exploration and colonization. Current space law, by necessity, addresses broad principles rather than specific incidents. Nonetheless, it covers a variety of issues including commercial development, rescue agreements, object registration,…

  14. TIBIAL PLATEAU FRACTURES

    PubMed Central

    Júnior, Mauricio Kfuri; Fogagnolo, Fabrício; Bitar, Rogério Carneiro; Freitas, Rafael Lara; Salim, Rodrigo; Jansen Paccola, Cleber Antonio

    2015-01-01

    Tibial plateau fractures are joint lesions that require anatomical reduction of joint surface and functional restoration of mechanical axis of a lower limb. Patient profile, soft tissue conditions, presence of associated injuries and the available infrastructure for the treatment all contribute to the decision making about the best treatment for these fractures. High-energy fractures are usually approached in a staged manner respecting the principle of damage control, and are primarily targeted to maintain limb alignment while the resolution unfavorable soft tissue conditions is pending. Low-energy trauma can be managed on a singlestage basis, provided soft tissues are not an adverse factor, with open reduction and internal fixation. Stable fixation and early painless joint movement are related to a better prognosis. New developments as locked plates, bone replacements, intraoperative 3D imaging are promising and will certainly contribute for less invasive procedures and better outcomes. PMID:27077054

  15. Plateau Rayleigh instability simulation.

    PubMed

    Mead-Hunter, Ryan; King, Andrew J C; Mullins, Benjamin J

    2012-05-01

    The well-known phenomena of Plateau-Rayleigh instability has been simulated using computational fluid dynamics (CFD). The breakup of a liquid film into an array of droplets on a cylindrical element was simulated using a volume-of-fluid (VOF) solver and compared to experimental observations and existing theory. It is demonstrated that the VOF method can correctly predict the breakup of thins films into an array of either axisymmetric droplets or clam-shell droplets, depending on the surface energy. The existence of unrealistically large films is precluded. Droplet spacing was found to show reasonable agreement with theory. Droplet motion and displacement under fluid flow was also examined and compared to that in previous studies. It was found that the presence of air flow around the droplet does not influence the stable film thickness; however, it reduces the time required for droplet formation. Novel relationships for droplet displacement were derived from the results. PMID:22512475

  16. CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY

    SciTech Connect

    BERGMAN, T. B.; STEFANSKI, L. D.; SEELEY, P. N.; ZINSLI, L. C.; CUSACK, L. J.

    2012-09-19

    THE CENTRAL PLATEAU REMEDIATION OPTIMIZATION STUDY WAS CONDUCTED TO DEVELOP AN OPTIMAL SEQUENCE OF REMEDIATION ACTIVITIES IMPLEMENTING THE CERCLA DECISION ON THE CENTRAL PLATEAU. THE STUDY DEFINES A SEQUENCE OF ACTIVITIES THAT RESULT IN AN EFFECTIVE USE OF RESOURCES FROM A STRATEGIC PERSPECTIVE WHEN CONSIDERING EQUIPMENT PROCUREMENT AND STAGING, WORKFORCE MOBILIZATION/DEMOBILIZATION, WORKFORCE LEVELING, WORKFORCE SKILL-MIX, AND OTHER REMEDIATION/DISPOSITION PROJECT EXECUTION PARAMETERS.

  17. Outer Solar System Nomenclature

    NASA Technical Reports Server (NTRS)

    Owen, Tobias C.

    1998-01-01

    The Principal Investigator's responsibilities on this grant fell into two categories according to his participation. In the nomenclature work of the International Astronomical Union (IAU). Owen is chair of the Task Group for the Outer Solar System. He is also a member of the IAU's Working Group on Planetary and Satellite Nomenclature (WGPSN) which is composed of the chairs of the several Task Groups plus the presidents of two IAU Commissions and several outside consultants. The WGPSN is presided over by its President, Professor Kaare Aksnes from the Rosseland Institute for Theoretical Astrophysics in Oslo, Norway.

  18. Jupiter's outer atmosphere.

    NASA Technical Reports Server (NTRS)

    Brice, N. M.

    1973-01-01

    The current state of the theory of Jupiter's outer atmosphere is briefly reviewed. The similarities and dissimilarities between the terrestrial and Jovian upper atmospheres are discussed, including the interaction of the solar wind with the planetary magnetic fields. Estimates of Jovian parameters are given, including magnetosphere and auroral zone sizes, ionospheric conductivity, energy inputs, and solar wind parameters at Jupiter. The influence of the large centrifugal force on the cold plasma distribution is considered. The Jovian Van Allen belt is attributed to solar wind particles diffused in toward the planet by dynamo electric fields from ionospheric neutral winds, and the consequences of this theory are indicated.

  19. Outer planets satellites

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1983-01-01

    The present investigation takes into account the published literature on outer planet satellites for 1979-1982. It is pointed out that all but three (the moon and the two Martian satellites) of the known planetary satellites are found in the outer solar system. Most of these are associated with the three regular satellite systems of Jupiter, Saturn, and Uranus. The largest satellites are Titan in the Saturn system and Ganymede and Callisto in the Jupiter system. Intermediate in size between Mercury and Mars, each has a diameter of about 5000 km. Presumably each has an internal composition about 60 percent rock and 40 ice, and each is differentiated with a dense core extending out about 75 percent of the distance to the surface, with a mantle of high-pressure ice and a crust of ordinary ice perhaps 100 km thick. Attention is also given to Io, Europa, the icy satellites of Saturn, the satellites of Uranus, the small satellites of Jupiter and Saturn, Triton and the Pluto system, and plans for future studies.

  20. Outer atmospheric research

    NASA Technical Reports Server (NTRS)

    Anderson, John L.

    1988-01-01

    The region above the earth from about 90 km to 150 km is a major part of the upper or outer atmosphere. It is relatively unexplored, being too high for balloons or aircraft and too low for persistent orbiting spacecraft. However, the concept of a tethered subsatellite, deployed downward from an orbiting, more massive craft such as the Space Shuttle, opens the possibility of a research capability that could provide global mapping of this region. The need for research in this thick spherical shell above the earth falls into two major categories: (1) scientific data for understanding and modeling the global atmosphere and thereby determining its role in the earth system, and (2) engineering data for the design of future aerospace vehicles that will operate there. This paper presents an overview and synthesis of the currently perceived research needs and the state-of-the-art of the proposed tethered research capability.

  1. Inner and outer beauty.

    PubMed

    Raymond, Kenneth N; Brown, Casey J

    2012-01-01

    Symmetry and pattern are precious forms of beauty that can be appreciated on both the macroscopic and molecular scales. Crystallographers have long appreciated the intimate connections between symmetry and molecular structure, reflected in their appreciation for the artwork of Escher. This admiration has been applied in the design of highly symmetrical coordination compounds. Two classes of materials are discussed: extended coordination arrays and discrete supramolecular assemblies. Extended coordination polymers have been implemented in gas separation and storage due to the remarkably porosity of these materials, aided by the ability to design ever-larger inner spaces within these frameworks. In the case of discrete symmetrical structures, defined inner and outer space present a unique aesthetic and chemical environment. The consequent host-guest chemistry and applications in catalysis are discussed. PMID:22076081

  2. Strategy for outer planets exploration

    NASA Technical Reports Server (NTRS)

    1975-01-01

    NASA's Planetary Programs Office formed a number of scientific working groups to study in depth the potential scientific return from the various candidate missions to the outer solar system. The results of these working group studies were brought together in a series of symposia to evaluate the potential outer planet missions and to discuss strategies for exploration of the outer solar system that were consistent with fiscal constraints and with anticipated spacecraft and launch vehicle capabilities. A logical, scientifically sound, and cost effective approach to exploration of the outer solar system is presented.

  3. Outer Solar System Nomenclature

    NASA Technical Reports Server (NTRS)

    Owen, Tobias C.; Grant, John (Technical Monitor)

    2003-01-01

    This grant has supported work by T. Owen and B. A. Smith on planetary and satellite nomenclature, carried out under the general auspices of the International Astronomical Union (IAU). The IAU maintains a Working Group on Planetary and Satellite Nomenclature (WGPSN) whose current chair is Prof.Kaare Aksnes of the Rosseland Institute for Theoretical Astrophysics in Oslo, Norway. Both Owen and Smith are members of the WGPSN; Owen as chair of the Outer Solar System Task Group, and Smith as chair of the Mars Task Group. The major activity during the last grant period (2002) was the approval of several new names for features on Mars by Smith's group and features on Jovian satellites plus new names for satellites of Jupiter, Saturn and Uranus by Owen's group. Much of this work was accomplished by e-mail exchanges, but the new nomenclature was formally discussed and approved at a meeting of the WGPSN held in conjunction with the Division for Planetary Sciences meeting in Birmingham, Alabama in October 2002.

  4. Will Career Plateauing Become a Bigger Problem?

    ERIC Educational Resources Information Center

    Dawson, Christopher M.

    1983-01-01

    Though career plateauing can be put off, it can seldom be entirely avoided. Distinction is made between plateauing of the job content type and plateauing of the structural or organizational type. Primary solutions involve job enrichment, performance goal adjustments, lateral transfers, or modified standards of appraisal. (SSH)

  5. The Leptospiral Outer Membrane

    PubMed Central

    Haake, David A; Zückert, Wolfram R

    2015-01-01

    The outer membrane (OM) is the front line of leptospiral interactions with their environment and the mammalian host. Unlike most invasive spirochetes, pathogenic leptospires must be able survive in both free-living and host-adapted states. As organisms move from one set of environmental conditions to another, the OM must cope with a series of conflicting challenges. For example, the OM must be porous enough to allow nutrient uptake, yet robust enough to defend the cell against noxious substances. In the host, the OM presents a surface decorated with adhesins and receptors for attaching to, and acquiring, desirable host molecules such as the complement regulator, Factor H. On the other hand, the OM must enable leptospires to evade detection by the host’s immune system on their way from sites of invasion through the bloodstream to the protected niche of the proximal tubule. The picture that is emerging of the leptospiral OM is that, while it shares many of the characteristics of the OMs of spirochetes and Gram-negative bacteria, it is also unique and different in ways that make it of general interest to microbiologists. For example, unlike most other pathogenic spirochetes, the leptospiral OM is rich in lipopolysaccharide (LPS). Leptospiral LPS is similar to that of Gram-negative bacteria but has a number of unique structural features that may explain why it is not recognized by the LPS-specific Toll-like receptor 4 of humans. As in other spirochetes, lipoproteins are major components of the leptospiral OM, though their roles are poorly understood. The functions of transmembrane OMPs in many cases are better understood thanks to homologies with their Gram-negative counterparts and the emergence of improved genetic techniques. This chapter will review recent discoveries involving the leptospiral OM and its role in leptospiral physiology and pathogenesis. Readers are referred to earlier, excellent summaries related to this subject (Adler and de la Peña Moctezuma

  6. Plateau uplift and climatic change

    SciTech Connect

    Ruddiman, W.F. ); Kutzbach, J.E. )

    1991-03-01

    The earth of 40 million years ago was a warm, wet place. Forests abounded; grasslands and deserts were rare. Then the planet began to cool. Regional climate extremes developed. Many causes have been postulated, including continental drift and diminishing atmospheric carbon dioxide. The authors offer a new theory: continental uplift created huge plateaus that altered circulation of the atmosphere. The two largest masses of high, rocky terrain in the Northern Hemisphere today are the area encompassing the Tibetan Plateau and Himalaya Mountains and the broad region of the American West centered on the Colorado Plateau. Geologic evidence indicates that these regions rose substantially during the past 40 million years. The authors focused their research on these plateaus.

  7. The Pajarito Plateau: a bibliography

    USGS Publications Warehouse

    Mathien, Frances Joan; Allen, Craig D.; Steen, Charlie R.

    1993-01-01

    This bibliography is the result of two initially independent projects. As the consulting archaeologist at Los Alamos National Laboratory (LANL), Charlie R. Steen collected entries at the suggestion of the staff of the Environmental Surveillance Group of the Health, Safety, and Environmental Division, HSE-8. The primary purpose was to aid the staff in evaluating cultural resources on LANL lands. In addition to works that related to the archaeology and history of the area, Steen included notations of a few books and articles in other fields such as geology and natural history. It was hoped that they also would be of value to other organizations and to students of past human activities on the Pajarito Plateau. At the same time, the National Park Service (NPS) was planning a major survey of Bandelier National Monument (BNM). As part of this plan, the author was asked to prepare a background document that described research previously carried out in the area, including an annotated bibliography. Although the survey would be limited to the park boundaries, the larger Pajarito Plateau is a more logical study area from physiographic, environmental, and cultural perspectives; hence the focus was on this larger region. Mathien (1986) also included some references to natural resources studies, particularly those initiated by NPS within Bandelier National Monument. Both bibliographies were made available to Colleen Olinger and Beverly Larson of the Health and Environmental Services Group at Los Alamos. They realized that while neither was complete, each included entries missing from the other. Larson suggested the two bibliographies be combined. (At this time, Craig Allen was studying the landscape of the Jemez Mountains [Allen 1984c, 1989]. His investigations included much detailed information on natural resource studies and were added in 1991 and 1992.) To limit the scope of their work, Steen and Mathien had chosen their parameter: the Pajarito Plateau. Geographically, the

  8. Turbine airfoil with outer wall thickness indicators

    DOEpatents

    Marra, John J; James, Allister W; Merrill, Gary B

    2013-08-06

    A turbine airfoil usable in a turbine engine and including a depth indicator for determining outer wall blade thickness. The airfoil may include an outer wall having a plurality of grooves in the outer surface of the outer wall. The grooves may have a depth that represents a desired outer surface and wall thickness of the outer wall. The material forming an outer surface of the outer wall may be removed to be flush with an innermost point in each groove, thereby reducing the wall thickness and increasing efficiency. The plurality of grooves may be positioned in a radially outer region of the airfoil proximate to the tip.

  9. Monuments of the Giza Plateau

    NASA Astrophysics Data System (ADS)

    Ruggles, Clive L. N.

    The colossal pyramids of the pharaohs Khufu (Cheops), Khafre (Chephren), and Menkaure (Mycerinus) have attracted a huge amount of astronomical interest over the years, both scholarly and popular. Less attention is usually given to the broader context of structures on the Giza Plateau. One of the most notorious ideas connecting the Giza Plateau with astronomy is that the three large pyramids are laid out on the ground so as to reflect the appearance of the three stars of Orion's Belt in the sky. This idea is unsupportable for several reasons but has succeeded in generating huge public interest. Of much greater serious interest is the fact that the three main pyramids were oriented cardinally to extraordinary precision, which raises the questions of why this was important and how it was achieved. Another idea that has attracted serious attention but also some confusion is that the orientations of some narrow shafts within Khufu's pyramid might have been deliberately aligned upon particular stars. The overall layout of monuments on the plateau may certainly have been designed so as to emphasize certain solar phenomena, for symbolic and ideological reasons relating to a dominant sun cult. It is also possible that it formed part of a wider cosmological "master plan" extending to other pyramids and temples up to 20 km distant.

  10. Thermoelectric Outer Planets Spacecraft (TOPS)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The research and advanced development work is reported on a ballistic-mode, outer planet spacecraft using radioisotope thermoelectric generator (RTG) power. The Thermoelectric Outer Planet Spacecraft (TOPS) project was established to provide the advanced systems technology that would allow the realistic estimates of performance, cost, reliability, and scheduling that are required for an actual flight mission. A system design of the complete RTG-powered outer planet spacecraft was made; major technical innovations of certain hardware elements were designed, developed, and tested; and reliability and quality assurance concepts were developed for long-life requirements. At the conclusion of its active phase, the TOPS Project reached its principal objectives: a development and experience base was established for project definition, and for estimating cost, performance, and reliability; an understanding of system and subsystem capabilities for successful outer planets missions was achieved. The system design answered long-life requirements with massive redundancy, controlled by on-board analysis of spacecraft performance data.

  11. PLATEAU IRIS SYNDROME--CASE SERIES.

    PubMed

    Feraru, Crenguta Ioana; Pantalon, Anca Delia; Chiselita, Dorin; Branisteanu, Daniel

    2015-01-01

    Plateau iris is characterized by closing the anterior chamber angle due to a large ciliary body or due to its anterior insertion that alters the position of iris periphery in respect to the trabecular meshwork. There are two aspects that need to be differentiated: plateau iris configuration and plateau iris syndrome. The first describes a situation when the iris root is flat and the anterior chamber is not shallow, the latter refers to a post laser iridotomy condition in which a patent iridotomy has removed the relative pupillary block, but goniscopically confirmed angle closure recurs without central shallowing of the anterior chamber. Isolated plateau iris syndrome is rare compared to plateau iris configuration. We hereby present two case reports of plateau iris syndrome in young patients who came to an ophthalmologic consult by chance. PMID:26978890

  12. η Carinae - The outer ejecta

    NASA Astrophysics Data System (ADS)

    Weis, K.

    2009-03-01

    η Carinae is a unique object among the most massive evolved stars in the LBV phase. The central object(s) is(are) surrounded by a complex circumstellar nebula ejected during more than one eruption in the 19th century. Beyond the well-defined edges of its famous bipolar nebula, the Homunculus, are additional nebulous features referred to as the outer ejecta. The outer ejecta contains a large variety of structures of very different sizes and morphologies distributed in a region 0.67 pc in diameter. Individual features in the outer ejecta are moving extremely fast, up to 3200 km/s, in general the expansion velocities are between 400-900 km/s. A consequence of these high velocities is that structures in the outer ejecta interact with the surrounding medium and with each other. The strong shocks that arise from these interactions give rise to soft X-ray emission. The global expansion pattern of the outer ejecta reveals an overall bipolar distribution, giving a symmetric structure to its morphologically more irregular appearance. The long, highly collimated filaments, called strings, are particularly unusual. The material in the strings follows a Hubble-flow and appears to originate at the central object.

  13. Origin of Outer Solar System

    NASA Technical Reports Server (NTRS)

    Holman, Matthew J.; Lindstrom, David (Technical Monitor)

    2005-01-01

    Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; ( 2 ) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; ( 5 ) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

  14. Vertical tectonics of the High Plateau region, Manihiki Plateau, Western Pacific, from seismic stratigraphy

    NASA Astrophysics Data System (ADS)

    Ai, Huirong-Anita; Stock, Joann M.; Clayton, Robert; Luyendyk, Bruce

    2008-01-01

    The Manihiki Plateau is an elevated oceanic volcanic plateau that was formed mostly in Early Cretaceous time by hotspot activity. We analyze new seismic reflection data acquired on cruise KIWI 12 over the High Plateau region in the southeast of the plateau, to look for direct evidence of the location of the heat source and the timing of uplift, subsidence and faulting. These data are correlated with previous seismic reflection lines from cruise CATO 3, and with the results at DSDP Site 317 at the northern edge of the High Plateau. Seven key reflectors are identified from the seismic reflection profiles and the resulting isopach maps show local variations in thickness in the southeastern part of the High Plateau, suggesting a subsidence (cooling) event in this region during Late Cretaceous and up to Early Eocene time. We model this as a hotspot, active and centered on the High Plateau area during Early Cretaceous time in a near-ridge environment. The basement and Early Cretaceous volcaniclastic layers were formed by subaerial and shallow-water eruption due to the volcanic activity. After that, the plateau experienced erosion. The cessation of hotspot activity and subsequent heat loss by Late Cretaceous time caused the plateau to subside rapidly. The eastern and southern portions of the High Plateau were rifted away following the cessation of hot spot activity. As the southeastern portion of the High Plateau was originally higher and above the calcium carbonate compensation depth, it accumulated more sediments than the surrounding plateau regions. Apparently coeval with the rapid subsidence of the plateau are normal faults found at the SE edge of the plateau. Since Early Eocene time, the plateau subsided to its present depth without significant deformation.

  15. The controversial age of Kilimanjaro's plateau glaciers

    NASA Astrophysics Data System (ADS)

    Uglietti, Chiara; Zapf, Alexander; Szidat, Sönke; Salazar, Gary; Hardy, Doug; Schwikowski, Margit

    2015-04-01

    Interpreting climate signals contained in natural archives requires a precise chronology. Radiocarbon analysis can be a powerful tool for dating high-altitude ice cores, especially for the lowermost segments for which ice flow-induced thinning limits the counting of annual layers. Radiocarbon dating has been applied to ice cores containing sufficient organic material, which is a limiting factor to the wider application of this technique. We present a novel radiocarbon dating approach using carbonaceous aerosols enclosed in the ice to help resolve the debate about the age of the Kilimanjaro's plateau glaciers. Paleoclimate reconstructions based on six ice cores drilled in 2000 assigned a basal age of 11'700 years. A recent study claims recurring cycles of waxing and waning controlled primarily by atmospheric moisture and an absence of the ice bodies was suggested for 1200 AD. The Kilimanjaro ice fields are subject to rapid areal shrinkage and thinning and are expected to disappear within several decades. Resolving the controversy of the time frame for the extinction of the Kilimanjaro ice might have wide implications for the understanding of the natural climate variability in the tropics. A stratigraphic sequence of samples from the exposed vertical ice cliffs at the margins of the Northern Ice Field (NIF) was collected in 2011. A total of 45 horizontal short cores (50 cm length) were extracted from 22 horizons characterized by varying micro-particle concentrations. Additionally, 3 samples were taken from the glacier surface to investigate a potential age offset. All samples were shipped frozen to Paul Scherrer Institute, decontaminated in a cold room by removing the outer layer (0.3 mm) and by rinsing the samples with ultra-pure water. The insoluble carbonaceous particles were filtrated by using freshly preheated quartz fibre filters. Procedural blanks were estimated using artificial ice blocks of frozen ultra-pure water treated as real ice samples and were

  16. Outward growth of Tibetan Plateau: Insights from joint inversion of lithosphere structure

    NASA Astrophysics Data System (ADS)

    Song, X.; Li, J.; Bao, X.; Zhu, L.

    2014-12-01

    Models for the growth of the Tibetan plateau have been a subject of great debate for decades. Here we add to the debate with new insights from an advanced imaging of the lithosphere structure of the western China. To resolve the ambiguity of model parameters and to improve resolution in seismic imaging, a combination of different data sets that have sensitivities to different parameters is required. We've recently developed joint-inversion methods involving Pn travel times, receiver functions, and surface wave dispersion measurements and applied them systematically to seismic stations in western China to obtain improved 3D P and S lithosphere models. Our models show significantly higher Vp/Vs ratios in northern Himalaya Block and southern Qiangtang Block than in the Lhasa Block. Mid-crustal low velocity zone (LVZ) is observed under much of the Tibetan Plateau. However, it is much more pronounced under the outer regions of the plateau (the Himalaya and Qiangtang Blocks) than under its interior (the Lhasa Block). The location of pronounced mid-crustal LVZ correlates (anti-correlates) with the distribution of seismicity in the plateau; the low seismicity areas have more pronounced LVZs and greater Vp/Vs values and the high seismic areas have less pronounced LVZs and smaller Vp/Vs values. The observations support the existence of a proto-Tibetan Plateau core and the outward growth of the margins at a later stage after the India-Eurasian collision (Wang C.S. et al., PNAS, 2008). The proto-plateau is more rigid and can sustain stress to cause brittle failure of earthquakes while the materials at the margins are weaker and can be subject to plastic deformation with much less seismicity. In this model, the proto-plateau core acts as an efficient medium for the stress transfer from the collision front to the margins for the outward growth of the plateau. The crust and mantle lithosphere act as a coherent unit as indicated by the consistent pattern of seismic anomalies with

  17. Mesozoic evolution and exploration potential of the western Exmouth Plateau, Australia

    SciTech Connect

    Buffler, R.T. ); Exon, N.F. )

    1991-03-01

    A regional grid of seismic data across the western Exmouth Plateau combined with recent ODP drilling results (Sites 762, 763, and 766) provide new ideas about the sedimentary history, tectonic evolution, and exploration potential of the area. The outer plateau is underlain by a thick section of regionally tilted, block-faulted, largely fluvial-deltaic, late Paleozoic-Triassic sediments. These sediments grade westward into an acoustically transparent basement interpreted to be Late Triassic-Early Jurassic intermediate volcanics. The western plateau is flanked on the northwest and southwest by the Gascoyne and Cuvier ocean basins, respectively, formed during the Lower Cretaceous when Greater India separated from Australia. Thermal doming of the margins in earliest Cretaceous just prior to initial rifting provided a southerly source area for the Barrow delta as well as local source areas for a thick, Barrow-equivalent sandstone unit along the western margin. Continued local uplift of the western margin during initial rifting (Late Valanginian-Hauterivian) provided shallow water source areas of local clastic wedges that prograded both eastward onto the plateau as well as westward into newly formed deepwater rift basins. This was followed by rapid subsidence of the plateau and deposition of deepwater shales and carbonates during the remainder of the Cretaceous and Cenozoic. Inferred source rocks (gas ) in the Triassic section, abundant reservoir rocks in the Triassic and overlying Lower Cretaceous, and overlying Cretaceous and Cenozoic seal, plus several episodes of thermal activity make the regional high along the western margin of the Exmouth Plateau a possible target for future deepwater exploration.

  18. Turbine airfoil with a compliant outer wall

    DOEpatents

    Campbell, Christian X.; Morrison, Jay A.

    2012-04-03

    A turbine airfoil usable in a turbine engine with a cooling system and a compliant dual wall configuration configured to enable thermal expansion between inner and outer layers while eliminating stress formation in the outer layer is disclosed. The compliant dual wall configuration may be formed a dual wall formed from inner and outer layers separated by a support structure. The outer layer may be a compliant layer configured such that the outer layer may thermally expand and thereby reduce the stress within the outer layer. The outer layer may be formed from a nonplanar surface configured to thermally expand. In another embodiment, the outer layer may be planar and include a plurality of slots enabling unrestricted thermal expansion in a direction aligned with the outer layer.

  19. Physics of the outer heliosphere

    SciTech Connect

    Gazis, P.R. )

    1991-01-01

    Major advances in the physics of the outer heliosphere are reviewed for the 1987-1990 time frame. Emphasis is placed on five broad topics: the detailed structure of the solar wind at large heliocentric distances, the global structure of the interplanetary field, latidudinal variations and meridional flows, radial and temporal variations, and the interaction of the solar wind with the local interstellar medium. 122 refs.

  20. Origin of Outer Solar System

    NASA Technical Reports Server (NTRS)

    Holman, Matthew J.; Boyce, J. (Technical Monitor)

    2003-01-01

    We feel that at the present moment the available theoretical models of the Kuiper belt are still in advance of the data, and thus our main task has been to conduct observational work guided by theoretical motivations. Our efforts over the past year can be divided into four categories: A) Wide-field Searches for Kuiper Belt Objects; B) Pencil-beam Searches for Kuiper Belt Objects; C) Wide-field Searches for Moons of the Outer Planets; D) Pencil-beam Searches for Faint Uranian and Neptunian Moons; E) Recovery Observations. As of April 2002, we have conducted several searches for Kuiper belt objects using large-format mosaic CCD camera on 4-meter class telescopes. In May 1999, we used the Kitt Peak 4-meter with the NOAO Mosaic camera we attempted a search for KBOs at a range of ecliptic latitudes. In addition to our wide-field searches, we have conducted three 'pencil-beam' searches in the past year. In a pencil-beam search we take repeated integrations of the same field throughout a night. After preprocessing the resulting images we shift and recombine them along a range of rates and directions consistent with the motion of KBOs. Stationary objects then smear out, while objects moving at near the shift rate appear as point sources. In addition to our searches for Kuiper belt objects, we are completing the inventory of the outer solar system by search for faint satellites of the outer planets. In August 2001 we conducted pencil beam searches for faint Uranian and Neptunian satellites at CFHT and CTIO. These searches resulted in the discover of two Neptunian and four Uranian satellite candidates. The discovery of Kuiper belt objects and outer planet satellites is of little use if the discoveries are not followed by systematic, repeated astrometric observations that permit reliable estimates of their orbits.

  1. 76 FR 54787 - Outer Continental Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ... Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer Continental Shelf Block Diagrams AGENCY... revised North American Datum of 1927 (NAD 27) Outer Continental Shelf Official Protraction Diagram,...

  2. 76 FR 2919 - Outer Continental Shelf Official Protraction Diagram and Supplemental Official Outer Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf Official Protraction Diagram and Supplemental Official Outer Continental Shelf Block Diagrams AGENCY: Bureau of Ocean... American Datum of 1983 (NAD 83) Outer Continental Shelf Official Protraction Diagram and...

  3. Plateau borders of smectic liquid crystalline films

    NASA Astrophysics Data System (ADS)

    Trittel, Torsten; Aldred, Ruth; Stannarius, Ralf

    2011-06-01

    We investigate the geometrical properties of Plateau borders in an arrangement of connected smectic A free standing films. The geometry is chosen such that a circular Plateau border surrounds a planar smectic film and connects it with two smectic catenoids. It is demonstrated that, similar to soap films, the smectic film geometry can be described by a negative line tension of the circular contact region. Thus, the equilibrium angle between the films depends upon the liquid content in this region, and with increasing liquid content, deviations from Plateau's rule are observed. The experimental results are qualitatively comparable to soap films. A possible origin of slight quantitative differences is discussed.

  4. Plateau effects on diurnal circulation patterns

    SciTech Connect

    Reiter, E.R.; Tang, M.

    1984-04-01

    The diurnal variation of 850 mb heights, the detailed distribution of which could be assessed by the inclusion of surface data, and of resultant winds over, and in the vicinity of, the Great Basin reveals clearly a plateau-wind circulation during summer. This circulation reverses between day and night and appears to include the low-level jet stream over Texas and Oklahoma, as well as the time of occurrence of thunderstorms. This plateau circulation system interacts with local mountain-valley breeze systems. The thickness of the daytime inflow and nighttime outflow layer over the plateau is approximately 2 km. 19 references, 11 figures, 1 table.

  5. [Hypoxic adaptation of the hearts of plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae)].

    PubMed

    Qi, Xin-Zhang; Wang, Xiao-Jun; Zhu, Shi-Hai; Rao, Xin-Feng; Wei, Lian; Wei, Deng-Bang

    2008-06-25

    Plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzniae) are native to the Qinghai-Tibet plateau. To study their adaptive mechanisms, the ratios of heart weight to body weight (HW/BW) and right to left ventricular plus septum weights [RV/(LV+S)] were determined; the microvessel density (MVD) of cardiac muscle were measured by immunohistochemical staining; the numerical density on area (N(A)), volume density (V(V)), specific surface (δ), and surface density (S(V)) of mitochondria were obtained by microscopy and stereology; the contents of myoglobin (Mb) and lactic acid (LD), and the activity of lactate dehydrogenase (LDH) in cardiac muscle were analyzed by spectrophotometer. The results showed that the HW/BW of plateau zokor [(4.55±0.26)%] and plateau pika [(4.41±0.38)%] was significantly greater than that of Sprague-Dawley (SD) rat [(3.44±0.41)%] (P<0.05), but the RV/(LV+S) [(22.04±1.98)%, (25.53±3.41)%] was smaller than that of SD rats [(44.23±3.87)%] (P<0.05). The MVD and N(A) of cardiac muscle were 1688.631±250.253 and 0.768±0.123 in SD rat, 2002.888±367.466 and 0.868±0.159 in plateau pika and 2 990.643±389.888 and 1.012±0.133 in plateau zokor. The V(V) of mitochondria in plateau zokor (0.272±0.045) was significantly lower than that in plateau pika (0.343±0.039) and SD rat (0.321±0.048) (P<0.05), while the δ of mitochondria in plateau zokor (9.409±1.238) was higher than that in plateau pika (6.772±0.892) and SD rat (7.287±1.373) (P<0.05). The S(V) of mitochondria in plateau pika (2.322±0.347) was not obviously different from that in plateau zokor (2.468±0.380) and SD rat (2.227±0.377), but that in plateau zokor was significantly higher than that in SD rat (P<0.05). The contents of Mb in cardiac muscle of plateau zokor [(763.33±88.73) nmol/g] and plateau pika [(765.96±28.47) nmol/g] were significantly higher than that of SD rat [(492.38±72.14) nmol/g] (P<0.05), the content of LD in plateau zokor [(0.57±0.06) mmol/L] was

  6. Geometrical interpretation for the outer SU(3) outer multiplicity label

    NASA Technical Reports Server (NTRS)

    Draayer, Jerry P.; Troltenier, D.

    1995-01-01

    A geometrical interpretation for the outer multiplicity rho that occurs in a reduction of the product of two SU(3) representations, (lambda(sub pi), mu(sub pi)) x (lambda(sub nu), mu(sub nu)) approaches sigma(sub rho)(lambda, mu)(sub rho), is introduced. This coupling of proton (pi) and neutron (nu) representations arises, for example, in both boson and fermion descriptions of heavy deformed nuclei. Attributing a geometry to the coupling raises the possibility of introducing a simple interaction that provides a physically meaningful way for distinguishing multiple occurrences of (lambda, mu) values that can arise in such products.

  7. Career Plateauing: Implications for Career Development Specialists.

    ERIC Educational Resources Information Center

    Weiner, Andrew; And Others

    1992-01-01

    Reaction to career plateaus depends on the employee's resources as well as the organization's response. Counseling, training and development, job enrichment, and other activities can minimize the stressful effects of involuntary plateauing. (SK)

  8. Magnetospheres of the outer planets

    SciTech Connect

    Cheng, A.F.

    1986-12-01

    The magnetospheres of the outer planets have been shown by Voyager explorations to strongly interact with the surfaces and atmospheres of their planetary satellites and rings. In the cases of Jupiter, Saturn and Uranus, the processes of charged particle sputtering, neutral gas cloud formation, and rapid plasma injection from the ionization of the neutral clouds, have important implications both for the magnetospheres as a whole and for the surfaces and atmospheres of their satellites. The general methodology employed in these researches has involved comparisons of the planetary magnetospheres in order to identify common physical processes. 16 references.

  9. New Exploration of Kerguelen Plateau Margins

    NASA Astrophysics Data System (ADS)

    Vially, R.; Roest, W. R.; Loubrieu, B.; Courreges, E.; Lecomte, J.; Patriat, M.; Pierre, D.; Schaming, M.; Schmitz, J.

    2008-12-01

    France ratified the United Nations Convention on the Law of the Sea in 1996, and has since undertaken an ambitious program of bathymetric and seismic data acquisition (EXTRAPLAC Program) to support claims for the extension of the legal continental shelf, in accordance with Article 76 of this convention. For this purpose, three oceanographic surveys took place on board of the R/V Marion Dufresne II on the Kerguelen Plateau, in Southern Indian Ocean: MD137-Kergueplac1 (February 2004), MD150-Kergueplac2 (October 2005) and MD165-Kergueplac3 (January 2008), operated by the French Polar Institute. Thus, more than 20 000 km of multibeam bathymetric, magnetic and gravimetric profiles, and almost 6 000 km of seismic profiles where acquired during a total of 62 days of survey in the study area. Ifremer's "rapid seismic" system was used, comprised of 4 guns and a 24 trace digital streamer, operated at speeds up to 10 knots. In addition to its use for the Extraplac Program, the data set issued from these surveys gives the opportunity to improve our knowledge of the structure of the Kerguelen Plateau and more particularly of its complex margins. In this poster, we will show the high resolution bathymetry (200 m) data set, that allows us to specify the irregular morphology of the sea floor in the north Kerguelen Plateau, characterised by ridges and volcanoes chains, radial to the plateau, that intersect the oceanic basin on the NE edge of the Kerguelen Plateau. We will also show magnetic and gravity data, which help us to understand the setting up of the oceanic plateau and the kinematics reconstructions. The seismic profiles show that the acoustic basement of the plateau is not much tectonised, and displays a very smooth texture, clearly contrasting it from typical oceanic basement. Both along the edge of the plateau as in the abyssal plain, sediments have variable thicknesses. The sediments on the margin of the plateau are up to 1200 meters thick and display irregular

  10. Cluster growth modeling of plateau erosion

    NASA Technical Reports Server (NTRS)

    Stark, Colin P.

    1994-01-01

    The pattern of erosion of a plateau along an escarpment may be modeled usng cluster growth techniques, recently popularized in models of drainage network evolution. If erosion on the scarp takes place in discrete events at rates subject to local substrate strength, the whole range of behavior is described by a combination of three cluster growth mechanisms: invasion percolation, Eden growth and diffusion-limited aggregation (DLA). These model the relative importance of preexisting substrate strength, background weathering, and seepage weathering and erosion respectively. The rate of seepage processes is determined by the efflux of groundwater at the plateau margin, which in turn is determined by the pressure field in the plateau aquifer. If this process acted alone, it would produce erosion patterns in the form of Laplacian fractals, with groundwater recharge from a distant source, or Poissionian fractals, with groundwater recharge uniform over the plateau. DLA is used to mimic the Laplacian or Poissonian potential field and the corresponding seepage growth process. The scaling structure of clusters grown by pure DLA, invasion percolation, or Eden growth is well known; this study presents a model which combines all three growth mechanisms for the first time. Mixed growth processes create clusters with different scaling properties and morphologies over distinct length scale ranges, and this is demonstrable in natural examples of plateau erosion.

  11. Outer Appearances Can Be Deceiving

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph shows the chemical composition of the rock at Gusev Crater dubbed 'Mazatzal' after it was brushed and ground by the Mars Exploration Rover Spirit's rock abrasion tool. The data, taken by the rover's alpha particle X-ray spectrometer over the last few sols, show that the amount of chlorine and sulfur tri-oxide in Mazatzal first increased after brushing, then diminished after grinding. The interior of the rock appears to have the same chemical make-up as other volcanic or basalt rocks studied in the Gusev Crater area ('Adirondack' and 'Humphrey'). Its outer coating or rind, on the other hand, appears to be of a different constitution. Scientists are still puzzling out the implications of these data.

    The larger symbols on the graph represent inferred rock compositions, while the smaller symbols are actual data points. Observations were made at the target dubbed 'New York' on Mazatzal.

  12. Aft outer rim seal arrangement

    DOEpatents

    Lee, Ching-Pang; Tham, Kok-Mun; Schroeder, Eric; Meeroff, Jamie; Miller, Jr., Samuel R; Marra, John J; Campbell, Christian X

    2015-04-28

    An outer rim seal arrangement (10), including: an annular rim (70) centered about a longitudinal axis (30) of a rotor disc (31), extending fore and having a fore-end (72), an outward-facing surface (74), and an inward-facing surface (76); a lower angel wing (62) extending aft from a base of a turbine blade (22) and having an aft end (64) disposed radially inward of the rim inward-facing surface to define a lower angel wing seal gap (80); an upper angel wing (66) extending aft from the turbine blade base and having an aft end (68) disposed radially outward of the rim outward-facing surface to define a upper angel wing seal gap (80, 82); and guide vanes (100) disposed on the rim inward-facing surface in the lower angel wing seal gap. Pumping fins (102) may be disposed on the upper angel wing seal aft end in the upper angel wing seal gap.

  13. Chemistry of the outer planets

    NASA Technical Reports Server (NTRS)

    Scattergood, Thomas W.

    1992-01-01

    Various aspects were studied of past or present chemistry in the atmospheres of the outer planets and their satellites using lab simulations. Three areas were studied: (1) organic chemistry induced by kinetically hot hydrogen atoms in the region of Jupiter's atmosphere containing the ammonia cirrus clouds; (2) the conversion of NH3 into N2 by plasmas associated with entry of meteors and other objects into the atmosphere of early Titan; and (3) the synthesis of simple hydrocarbons and HCN by lightning in mixtures containing N2, CH4, and NH3 representing the atmospheres of Titan and the outer planets. The results showed that: (1) hot H2 atoms formed from the photodissociation of NH3 in Jupiter's atmosphere could account for some of the atmospheric chemistry in the ammonia cirrus cloud region; (2) the thermalization of hot H2 atoms in atmospheres predominated by molecular H is not as rapid as predicted by elastic collision theory; (3) the net quantum loss of NH3 in the presence of a 200 fold excess of H2 is 0.02, much higher than was expected from the amount of H2 present; (4) the conversion of NH3 into N2 in plasmas associated with infalling meteors is very efficient and rapid, and could account for most of the N2 present on Titan; (5) the yields of C2H2 and HCN from lightning induced chemistry in mixtures of CH4 and N2 is consistent with quenched thermodynamic models of the discharge core; and (6) photolysis induced by the UV light emitted by the gases in the hot plasmas may account for some, if not most, of the excess production of C2H6 and the more complex hydrocarbons.

  14. Mode and mechanisms of plateau uplifts

    NASA Technical Reports Server (NTRS)

    Mcgetchin, T. R.; Burke, K. C.; Thompson, G. A.; Young, R. A.

    1980-01-01

    The mode and mechanisms of plateau uplifts are reported, based on discussions which occurred as part of a conference on plateau uplifts sponsored by the Inter-Union Commission on Geodynamics and the Lunar and Planetary Institute. Major plateaus and high plains of the world are discussed with emphasis on the Colorado Plateau, which possesses a shield-like crust 45 km thick and occupies most of eastern Utah and parts of Colorado, Arizona, and New Mexico. Several uplift mechanisms are described, including thermal expansion due to a deep mantle plume or hot spot, and hydration reactions such as serpentinization. It is concluded that uplifts are most commonly associated with either subduction and its direct effects, or deep-seated thermal disturbances.

  15. The Hikurangi Plateau: Tectonic Ricochet and Accretion

    NASA Astrophysics Data System (ADS)

    Willis, David; Moresi, Louis; Betts, Peter; Whittaker, Joanne

    2015-04-01

    80 million years between interactions with different subduction systems provided time for the Hikurangi Plateau and Pacific Ocean lithosphere to cool, densify and strengthen. Neogene subduction of the Hikurangi Plateau occurring orthogonal to its Cretaceous predecessor, provides a unique opportunity to explore how changes to the physical properties of oceanic lithosphere affect subduction dynamics. We used Underworld to build mechanically consistent collision models to understand the dynamics of the two Hikurangi collisions. The Hikurangi Plateau is a ~112 Ma, 15km thick oceanic plateau that has been entrained by subduction zones immediately preceding the final break-up of Eastern Gondwana and currently within the active Hikurangi Margin. We explore why attempted subduction of the plateau has resulted in vastly different dynamics on two separate occasions. Slab break-off occured during the collision with Gondwana, currently there is apparent subduction of the plateau underneath New Zealand. At ~100Ma the young, hot Hikurangi Plateau, positively buoyant with respect to the underlying mantle, impacted a Gondwana Margin under rapid extension after the subduction of an mid-ocean ridge 10-15Ma earlier. Modelling of plateaus within young oceanic crust indicates that subduction of the thickened crust was unlikely to occur. Frontal accretion of the plateau and accompanying slab break-off is expected to have occured rapidly after its arrival. The weak, young slab was susceptible to lateral propagation of the ~1500 km window opened by the collision, and break-off would have progressed along the subduction zone inhibiting the "step-back" of the trench seen in older plates. Slab break-off coincided with a world-wide reorganisation of plate velocites, and orogenic collapse along the Gondwana margin characterised by rapid extension and thinning of the over-riding continental plate from ~60 to 30km. Following extension, Zealandia migrated to the NW until the Miocene allowing the

  16. Compartment syndrome after tibial plateau fracture☆

    PubMed Central

    Pitta, Guilherme Benjamin Brandão; dos Santos, Thays Fernanda Avelino; dos Santos, Fernanda Thaysa Avelino; da Costa Filho, Edelson Moreira

    2014-01-01

    Fractures of the tibial plateau are relatively rare, representing around 1.2% of all fractures. The tibia, due to its subcutaneous location and poor muscle coverage, is exposed and suffers large numbers of traumas, not only fractures, but also crush injuries and severe bruising, among others, which at any given moment, could lead compartment syndrome in the patient. The case is reported of a 58-year-old patient who, following a tibial plateau fracture, presented compartment syndrome of the leg and was submitted to decompressive fasciotomy of the four right compartments. After osteosynthesis with internal fixation of the tibial plateau using an L-plate, the patient again developed compartment syndrome. PMID:26229779

  17. HANFORD SITE CENTRAL PLATEAU CLEANUP COMPLETION STRATEGY

    SciTech Connect

    BERGMAN TB

    2011-01-14

    Cleanup of the Hanford Site is a complex and challenging undertaking. The U.S. Department of Energy (DOE) has developed a comprehensive vision for completing Hanford's cleanup mission including transition to post-cleanup activities. This vision includes 3 principle components of cleanup: the {approx}200 square miles ofland adjacent to the Columbia River, known as the River Corridor; the 75 square miles of land in the center of the Hanford Site, where the majority of the reprocessing and waste management activities have occurred, known as the Central Plateau; and the stored reprocessing wastes in the Central Plateau, the Tank Wastes. Cleanup of the River Corridor is well underway and is progressing towards completion of most cleanup actions by 2015. Tank waste cleanup is progressing on a longer schedule due to the complexity of the mission, with construction of the largest nuclear construction project in the United States, the Waste Treatment Plant, over 50% complete. With the progress on the River Corridor and Tank Waste, it is time to place increased emphasis on moving forward with cleanup of the Central Plateau. Cleanup of the Hanford Site has been proceeding under a framework defmed in the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement). In early 2009, the DOE, the State of Washington Department of Ecology, and the U.S. Environmental Protection Agency signed an Agreement in Principle in which the parties recognized the need to develop a more comprehensive strategy for cleanup of the Central Plateau. DOE agreed to develop a Central Plateau Cleanup Completion Strategy as a starting point for discussions. This DOE Strategy was the basis for negotiations between the Parties, discussions with the State of Oregon, the Hanford Advisory Board, and other Stakeholder groups (including open public meetings), and consultation with the Tribal Nations. The change packages to incorporate the Central Plateau Cleanup Completion Strategy were signed by

  18. Tectonomagmatic Associations on the Central Andean Plateau

    NASA Astrophysics Data System (ADS)

    de Silva, S. L.; Viramonte, J. G.

    2012-12-01

    The Neogene evolution of the Central Andes is characterized by a strong association between plate convergence, mountain building and plateau formation, and magmatism. Plateau uplift by crustal shortening and thickening in the lower crust is broadly coincident with large scale silicic magmatism defined by the Neogene Central Andean ignimbrite province. Of particular interest here are the spatiotemporal correlations between silicic magmatism and tectonic evolution of the Altiplano-Puna plateau. Although magmatism is driven by the subduction-related flux from mantle to crust, the shift to "crustal" magmatism as indicated by elevated crustal isotopic indices after ~10Ma suggests a link between crustal thickening, plateau formation and silicic magmatism. In particular, elevated geotherms associated with crustal thickening and enhanced mantle flux associated with lithospheric delamination may have played a role in thermally preparing the Central Andean crust for enhanced silicic magma production during the extensive Neogene ignimbrite flare-up. Emplacement of these magmas in the upper crust throughout the Neogene may have fuelled a period of significant interaction between magmatism and tectonism on the plateau. With particular reference to the 21° to 24°S segment of the Central Andes, spatial and structural coincidence of calderas of the Altiplano Puna Volcanic Complex with the NW-SE striking Calama-Olacapata-El Toro fault zone suggests significant tectonomagmatic interaction. Location of calderas suggest that these regional faults focused magma intrusion and storage, while spatially and temporally correlated eruption pulses connote a tectonic control. Indeed, current thermomechanical models of magma chamber development and eruption triggering promote a role for external triggering of "perched" upper crustal magma chambers. This might have been achieved by melt-enhanced deformation, or alternatively, significant uplift (~1km) associated with the development of large

  19. Insufficiency fractures of the tibial plateau

    SciTech Connect

    Manco, L.G.; Schneider, R.; Pavlov, H.

    1983-06-01

    An insufficiency fracture of the tibial plateau may be the cause of knee pain in patients with osteoporosis. The diagnosis is usually not suspected until a bone scan is done, as initial radiographs are often negative or inconclusive and clinical findings are nonspecific and may simulate osteoarthritis or spontaneous osteonecrosis. In five of 165 patients referred for bone scans due to nontraumatic knee pain, a characteristic pattern of intense augmented uptake of radionuclide confined to the tibial plateau led to a presumptive diagnosis of insufficiency fracture, later confirmed on radiographs.

  20. Holocene cold events on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Mischke, Steffen; Zhang, Chengjun

    2010-06-01

    A lake sediment core from the eastern Tibetan Plateau was investigated by multi-proxy geochemical, sedimentological and magnetic analyses and its age determined using 14C AMS dating in an approach to use short-lived climate periods for a spatial assessment of the Holocene climate history on the Tibetan Plateau. Six cold events were identified from the Lake Ximencuo record which occurred between 10.3-10.0, 7.9-7.4, 5.9-5.5, 4.2-2.8, 1.7-1.3 and 0.6-0.1 cal ka BP. A comparison with previously published Holocene records from lake and peat sections, ice cores and glacial remains of the Tibetan Plateau revealed that the cold event starting around 4.2 cal ka BP had the most significant and widespread impact on almost all of the examined sites. This cold event lasted about a millennium in the western and central part of the Tibetan Plateau and possibly several hundred years longer at some sites in its eastern realm. The cold event inferred between 7.9 and 7.4 cal ka BP from Lake Ximencuo was recorded at a number of sites on the eastern Tibetan Plateau too and probably corresponds to a cold event identified around 8.2 cal ka BP at the sites on the western and central Tibetan Plateau. The coincidence with the 8.2 ka event of the North Atlantic region implies that the latter exerted a significant environmental impact on the Tibetan Plateau too. The cold spell between 10.3 and 10.0 cal ka BP was recorded at some marginal sites of the Tibetan Plateau but had apparently a less significant environmental impact. The more irregular pattern of cold events between about 7 cal ka BP and the onset of the cold event after 4.2 cal ka BP might be related to the catchment-specific response of the lake sediment and peat accumulation to the termination of the Holocene 'climatic optimum' on the Tibetan Plateau. The final two cold events between 1.7 and 1.3 cal ka BP and in the last several hundred years representing the Little Ice Age are more widely seen on the Tibetan Plateau although they

  1. Plateauing as an Occupational Phenomenon among Teachers and Administrators.

    ERIC Educational Resources Information Center

    Milstein, Mike M.

    The intent of this paper is to clarify the meaning of the "plateauing" of educators and its effects as a unique form of career stall. Initial definitions are followed by a summary of a presentation of and literature on plateauing and some preliminary findings about the extent of plateauing among educators and how they try to cope with it. Three…

  2. Central Tibetan Meso-Tethyan oceanic plateau

    NASA Astrophysics Data System (ADS)

    Zhang, Kai-Jun; Xia, Bin; Zhang, Yu-Xiu; Liu, Wei-Liang; Zeng, Lu; Li, Jian-Feng; Xu, Li-Feng

    2014-12-01

    We report the occurrences of the remnants of a Meso-Tethyan oceanic plateau, encompassing an area of ~ 2 × 105 km2 in central Tibet. The plateau remnants include large volumes of pillow basalt formed largely by emergent to subaerial eruption, minor ultramafic intrusives and cumulates, exotic blocks of limestone, radiolarian chert, graywacke, and shale. Isotopic and paleontological dating suggest two major plateau eruptive events at 193-173 Ma and at 128-104 Ma, respectively. The basalts are characterized by enrichment of incompatible elements and a wide range of Sr-Nd isotope composition (initial εNd from -3.71 to + 7.9, initial 87Sr/86Sr from 0.703927 to 0.707618). The trace element and Sr-Nd isotopic data suggest that these basalts are of affinity with those from the Kerguelen and Tethyan plumes, indicative of a plume mantle upwelling origin with involvement of continental material. The wholesale obduction of the Meso-Tethyan oceanic plateau, along with the dismembered normal oceanic crustal fragments, over the Tibetan continental crust could have given rise to perhaps 2 km elevation of central Tibet during the Late Cretaceous.

  3. Structure and sedimentary history of Exmouth Plateau

    SciTech Connect

    Exon, N.F.; Williamson, P.E.; Von Rad, U.

    1989-03-01

    The large, deep-water Exmouth Plateau off northwestern Australia has been actively explored for petroleum, and a giant gas accumulation has been found. Data from industry and research institutions have established its geological framework. The plateau has a basement of continental crust that was thinned and extended in the Permian. This is overlain by 10 km of Phanerozoic strata, with an average of more than 3 km of Triassic, about 1 km of Jurassic/Cretaceous, and 0.5 km of Cenozoic strata. The plateau separated from other parts of the northern margin of Gondwanaland in the Mesozoic. Latest Triassic and Jurassic rifting formed large north-northeast-trending fault blocks; in the Oxfordian a microcontinent drifted away to the northwest, forming the plateau's northern margin. The other margins developed in the Neocomian as Greater India separated from Australia - the western margin by rifting and the southern by shearing. Terrigenous input declined greatly at that time. This old continental margin, with its relatively thin Mesozoic and Cenozoic sediments, was selected by the Ocean Drilling Program (ODP) for comprehensive and fully integrated sedimentologic, biostratigraphic, paleobathymetric, and subsidence studies.

  4. A Standard Atmosphere of the Antarctic Plateau

    NASA Technical Reports Server (NTRS)

    Mahesh, Ashwin; Lubin, Dan

    2004-01-01

    Climate models often rely on standard atmospheres to represent various regions; these broadly capture the important physical and radiative characteristics of regional atmospheres, and become benchmarks for simulations by researchers. The high Antarctic plateau is a significant region of the earth for which such standard atmospheres are as yet unavailable. Moreover, representative profiles from atmospheres over other regions of the planet, including &om the northern high latitudes, are not comparable to the atmosphere over the Antarctic plateau, and are therefore only of limited value as substitutes in climate models. Using data from radiosondes, ozonesondes and satellites along with other observations from South Pole station, typical seasonal atmospheric profiles for the high plateau are compiled. Proper representations of rapidly changing ozone concentrations (during the ozone hole) and the effect of surface elevation on tropospheric temperatures are discussed. The differences between standard profiles developed here and the most similar standard atmosphere that already exists - namely, the Arctic Winter profile - suggest that these new profiles will be extremely useful to make accurate representations of the atmosphere over the high plateau.

  5. Mud volcanism at the Manihiki-Plateau

    SciTech Connect

    Beiersdorf, H. )

    1990-06-01

    In February 1987 a complex of mud volcanoes was discovered on the northeastern edge of the Manihiki-Plateau during a cruise of R/V MOANA WAVE. Forty out of about 100 cones coalesce to form an edifice about 25 km in diameter, 1,900 m high, rising from a plateau depth of 3,200 m. SeaMARC II side-scan images suggest radial fluid sediment flow from the center of this feature. Recent foraminiferal ooze was cored from a satellite cone. One dredge haul from the summit of the edifice recovered burrowed limestone with embedded Middle Eocene foraminifera. It suggests that parts of the sedimentary basement cover of the Manihiki Plateau have been mobilized together with pore fluids and moved upward. The causes of the movement as well as its mechanism, however, remain unknown because of the lack of direct measurements. There is a likelihood that overpressured methane, generated from organic carbon-rich sediments, acts as driving force. Therefore, BGR submitted a proposal to the Federal Ministry of Research and Technology (BMFT) to investigate the mud volcano complex and reference area with the most relevant outcropping sedimentary sequence of the northeastern Manihiki Plateau in detail. The preliminary results from these investigations carried out with R/V SONNE in spring of 1990 are presented.

  6. Interiors and atmospheres of the outer planets

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.

    1991-01-01

    This theoretical/observational project constrains structure of outer planet atmospheres and interiors through observational data. The primary observation tool is through observations of occultations of stars by outer solar system objects, which yield information about atmospheric temperatures and dynamics, and planetary dimensions and oblateness. The theoretical work relates the data to interior structures in a variety of ways.

  7. Design Of Robots For Outer Space

    NASA Technical Reports Server (NTRS)

    Roston, Gerald P.

    1990-01-01

    Report discusses design of robots for use in zero gravity and vacuum, with attention to differences between requirements imposed on designs by outer space and by terrestrial applications. Terrestrial robots designed for multiple purposes and for minimal cost. Outer-space robots designed specialized to one task where cost has relatively low priority. Design optimal in one environment unlikely optimal in another.

  8. 76 FR 63654 - Outer Continental Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... Bureau of Ocean Energy Management Outer Continental Shelf Official Protraction Diagram, Lease Maps, and Supplemental Official Outer Continental Shelf Block Diagrams AGENCY: Bureau of Ocean Energy Management (BOEM), Interior. ACTION: Availability of revised North American Datum of 1927 (NAD 27) Outer Continental...

  9. Astroparticles: Messengers from Outer Space

    NASA Astrophysics Data System (ADS)

    Desiati, Paolo

    2016-07-01

    Since Galileo pointed a spyglass toward the sky, 400 years ago, observations empowered by man-made instrumentation have provided us with an enormous leap in the knowledge of how the Universe functions. More and more powerful optical telescopes made it possible for us to reach the farthest corners of space. At the same time, the advances in microphysics and the discovery of the electromagnetic spectrum, made it possible to directly look at the Universe in a way that our eyes cannot see. The discoveries of the intimate structure of matter, of subatomic particles and of how they interact with each other, have led astronomers to use the smallest objects in Nature to observe the farthest reaches of the otherwise invisible Universe. Not unlike Galileo, today we observe Outer Space with visible light and beyond, across the entire electromagnetic spectrum, from long wavelength radio waves to short wavelength gamma rays. But also with instruments detecting cosmic rays (the atomic nuclei we know on Earth) neutrinos (neutral subatomic particles that interact very weakly with matter) and gravitational waves (perturbations of spacetime predicted by General Relativity). Each cosmic messenger provides us with a unique piece of information about their source and the history of their journey to us. Modern astrophysics has the challenging goal to collect as much information as possible from all those messengers, to reconstruct the story of the Universe and how it became what it is today. This journey started with the unsettling discovery that we are only one minuscule dot in the immensity of the Universe and yet we are able to observe objects that are far in space and time. This journey is yet to complete its course, and the more we advance our knowledge, the more we need to understand. This interdisciplinary talk provides an overview of this journey and the future perspectives.

  10. Shield volcanism and lithospheric structure beneath the Tharsis plateau, Mars

    NASA Technical Reports Server (NTRS)

    Blasius, K. R.; Cutts, J. A.

    1976-01-01

    The heights of four great shield volcanoes, when interpreted as reflecting the local hydrostatic head on a common source of upwelling magma, provide significant constraints on models of lithospheric structure beneath the Tharsis plateau. If Bouguer gravity anomalies are modeled in terms of a variable thickness crust, and a two-component (crust/mantle) earth-like structure is assumed for the Martian lithosphere, the derived model lithosphere beneath the Tharsis plateau has the following properties: (1) the upper low-density 'crustal' component is thickened beneath the Tharsis plateau; (2) the lower high-density 'mantle' component is thinned beneath the Tharsis plateau; and (3) there is a net gradient on the base of the Martian lithosphere directed downward away from beneath the summit of the Tharsis plateau. A long history of magmatic intrusion is hypothesized to have been the cause of the updoming of the Tharsis plateau and the maintenance of the plateau in a state of only partial compensation.

  11. Hydrogeology of the Markagunt Plateau, Southwestern Utah

    USGS Publications Warehouse

    Spangler, Lawrence E.

    2010-01-01

    The Markagunt Plateau, in southwestern Utah, lies at an altitude of about 9,500 feet and is capped primarily by Quaternary-age basalt that overlies Eocene-age freshwater limestone of the Claron Formation. Over large parts of the Markagunt Plateau, dissolution of the Claron limestone and subsequent collapse of the overlying basalt have produced a terrain characterized by sinkholes as much as 1,000 feet across and 100 feet deep. Numerous large springs discharge from the basalt and underlying limestone on the plateau, including Mammoth Spring, one of the largest springs in Utah, with a discharge that can exceed 300 cubic feet per second. Discharge from Mammoth Spring is from the Claron Formation; however, recharge to the spring largely takes place by both focused and diffuse infiltration through the basalt that caps the limestone. Results of dye tracing to Mammoth Spring indicate that recharge originates largely southwest of the spring outside of the Mammoth Creek watershed, as well as from losing reaches along Mammoth Creek. Maximum groundwater travel time to the spring from dye-tracer tests during the snowmelt runoff period was about 1 week. Specific conductance and water temperature data from the spring show an inverse relation to discharge during snowmelt runoff and rainfall events, also indicating short groundwater residence times. Results of major-ion analyses for samples collected from Mammoth and other springs on the plateau indicate calcium-bicarbonate type water containing low (less than 200 mg/L) dissolved-solids concentrations. Investigations in the Navajo Lake area along the southern margin of the plateau have shown that water losing to sinkholes bifurcates and discharges to both Cascade and Duck Creek Springs, which subsequently flow into the Virgin and Sevier River basins, respectively. Groundwater travel times to these springs, on the basis of dye tracing, were about 8.5 and 53 hours, respectively. Similarly, groundwater travel time from Duck Creek

  12. Incorporation of squalene into rod outer segments

    SciTech Connect

    Keller, R.K.; Fliesler, S.J. )

    1990-08-15

    We have reported previously that squalene is the major radiolabeled nonsaponifiable lipid product derived from ({sup 3}H)acetate in short term incubations of frog retinas. In the present study, we demonstrate that newly synthesized squalene is incorporated into rod outer segments under similar in vitro conditions. We show further that squalene is an endogenous constituent of frog rod outer segment membranes; its concentration is approximately 9.5 nmol/mumol of phospholipid or about 9% of the level of cholesterol. Pulse-chase experiments with radiolabeled precursors revealed no metabolism of outer segment squalene to sterols in up to 20 h of chase. Taken together with our previous absolute rate studies, these results suggest that most, if not all, of the squalene synthesized by the frog retina is transported to rod outer segments. Synthesis of protein is not required for squalene transport since puromycin had no effect on squalene incorporation into outer segments. Conversely, inhibition of isoprenoid synthesis with mevinolin had no effect on the incorporation of opsin into the outer segment. These latter results support the conclusion that the de novo synthesis and subsequent intracellular trafficking of opsin and isoprenoid lipids destined for the outer segment occur via independent mechanisms.

  13. PLATEAUING COSMIC RAY DETECTORS TO ACHIEVE OPTIMUM OPERATING VOLTAGE

    SciTech Connect

    Knoff, E.N.; Peterson, R.S.

    2008-01-01

    Through QuarkNet, students across the country have access to cosmic ray detectors in their high school classrooms. These detectors operate using a scintillator material and a photomultiplier tube (PMT). A data acquisition (DAQ) board counts cosmic ray hits from the counters. Through an online e-Lab, students can analyze and share their data. In order to collect viable data, the PMTs should operate at their plateau voltages. In these plateau ranges, the number of counts per minute remains relatively constant with small changes in PMT voltage. We sought to plateau the counters in the test array and to clarify the plateauing procedure itself. In order to most effectively plateau the counters, the counters should be stacked and programmed to record the number of coincident hits as well as their singles rates. We also changed the threshold value that a signal must exceed in order to record a hit and replateaued the counters. For counter 1, counter 2, and counter 3, we found plateau voltages around 1V. The singles rate plateau was very small, while the coincidence plateau was very long. The plateau voltages corresponded to a singles rate of 700–850 counts per minute. We found very little effect of changing the threshold voltages. Our chosen plateau voltages produced good performance studies on the e-Lab. Keeping in mind the nature of the experiments conducted by the high school students, we recommend a streamlined plateauing process. Because changing the threshold did not drastically affect the plateau voltage or the performance study, students should choose a threshold value, construct plateau graphs, and analyze their data using a performance study. Even if the counters operate slightly off their plateau voltage, they should deliver good performance studies and return reliable results.

  14. Depletion of the Outer Asteroid Belt

    NASA Technical Reports Server (NTRS)

    Liou, Jer-Chyi; Malhotra, Renu

    1997-01-01

    During the early history of the solar system, it is likely that the outer planets changed their distance from the sun, and hence, their influence on the asteroid belt evolved with time. The gravitational influence of Jupiter and Saturn on the orbital evolution of asteroids in the outer asteroid belt was calculated. The results show that the sweeping of mean motion resonances associated with planetary migration efficiently destabilizes orbits in the outer asteroid belt on a time scale of 10 million years. This mechanism provides an explanation for the observed depletion of asteroids in that region.

  15. Electron transport fluxes in potato plateau regime

    SciTech Connect

    Shaing, K.C.; Hazeltine, R.D.

    1997-12-01

    Electron transport fluxes in the potato plateau regime are calculated from the solutions of the drift kinetic equation and fluid equations. It is found that the bootstrap current density remains finite in the region close to the magnetic axis, although it decreases with increasing collision frequency. This finite amount of the bootstrap current in the relatively collisional regime is important in modeling tokamak startup with 100{percent} bootstrap current. {copyright} {ital 1997 American Institute of Physics.}

  16. Freshwater Biogeography and Limnological Evolution of the Tibetan Plateau - Insights from a Plateau-Wide Distributed Gastropod Taxon (Radix spp.)

    PubMed Central

    von Oheimb, Parm Viktor; Albrecht, Christian; Riedel, Frank; Du, Lina; Yang, Junxing; Aldridge, David C.; Bößneck, Ulrich; Zhang, Hucai; Wilke, Thomas

    2011-01-01

    Background The Tibetan Plateau is not only the highest and largest plateau on earth; it is also home to numerous freshwater lakes potentially harbouring endemic faunal elements. As it remains largely unknown whether these lakes have continuously existed during the Last Glacial Maximum (LGM), questions arise as to whether taxa have been able to exist on the plateau since before the latest Pleistocene, from where and how often the plateau was colonized, and by which mechanisms organisms conquered remote high altitude lentic freshwater systems. In this study, species of the plateau-wide distributed freshwater gastropod genus Radix are used to answer these biogeographical questions. Methodology/Principal Findings Based on a broad spatial sampling of Radix spp. on the Tibetan Plateau, and phylogenetic analyses of mtDNA sequence data, three probably endemic and one widespread major Radix clade could be identified on the plateau. Two of the endemic clades show a remarkably high genetic diversity, indicating a relatively great phylogenetic age. Phylogeographical analyses of individuals belonging to the most widely distributed clade indicate that intra-plateau distribution cannot be explained by drainage-related dispersal alone. Conclusions/Significance Our study reveals that Radix spp. persisted throughout the LGM on the Tibetan Plateau. Therefore, we assume the continuous existence of suitable water bodies during that time. The extant Radix diversity on the plateau might have been caused by multiple colonization events combined with a relatively long intra-plateau evolution. At least one colonization event has a Palaearctic origin. In contrast to freshwater fishes, passive dispersal, probably by water birds, might be an important mechanism for conquering remote areas on the plateau. Patterns found in Radix spp. are shared with some terrestrial plateau taxa, indicating that Radix may be a suitable model taxon for inferring general patterns of biotic origin, dispersal and

  17. Site Selected for Colorado Plateau Coring

    NASA Astrophysics Data System (ADS)

    Geissman, John W.; Olsen, Paul E.; Kent, Dennis V.

    2010-04-01

    Colorado Plateau Coring Project Workshop, Phase 2: 100 Million Years of Climatic, Tectonic, and Biotic Evolution From Continental Coring; Albuquerque, New Mexico, 8-11 May 2009; A workshop was convened in New Mexico to plan for the Colorado Plateau Coring Project (CPCP) and identify the target site for initial coring. The giant continental and nearshore to shallow marine epicontinental basins of the American Southwest are particularly well exposed on the Colorado Plateau and its environs and contain a rich record of early Mesozoic (˜251-145 million years ago) strata. This time period was punctuated by two major mass extinctions and is notable for the evolutionary appearance of the modern biota and its apparent dramatic climate changes. Classic studies of these basins, their strata, and their fossils have made this sequence instrumental in framing the context for the early Mesozoic world. Ambiguities in temporal resolution, uncertainties in global correlations with other early Mesozoic strata, and major doubts about latitudinal position still hamper testing of competing climatic, biotic, and tectonic models for the evolution of western Pangea.

  18. Outer planet probe engineering model structural tests

    NASA Technical Reports Server (NTRS)

    Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

    1977-01-01

    A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

  19. Outer Membrane Permeability and Antibiotic Resistance

    PubMed Central

    Delcour, Anne H.

    2009-01-01

    Summary To date most antibiotics are targeted at intracellular processes, and must be able to penetrate the bacterial cell envelope. In particular, the outer membrane of Gram-negative bacteria provides a formidable barrier that must be overcome. There are essentially two pathways that antibiotics can take through the outer membrane: a lipid-mediated pathway for hydrophobic antibiotics, and general diffusion porins for hydrophilic antibiotics. The lipid and protein compositions of the outer membrane have a strong impact on the sensitivity of bacteria to many types of antibiotics, and drug resistance involving modifications of these macromolecules is common. This review will describe the molecular mechanisms for permeation of antibiotics through the outer membrane, and the strategies that bacteria have deployed to resist antibiotics by modifications of these pathways. PMID:19100346

  20. The outer solar system - Perspectives for exobiology

    NASA Technical Reports Server (NTRS)

    Owen, T.

    1974-01-01

    An attempt is made to summarize the current knowledge about the composition and structures of outer planet atmospheres with special emphasis on Jupiter, Saturn, and Titan. The nature of the substances which are responsible for the yellow coloration observed on both Jupiter and Saturn is discussed. The analysis of planetary conditions conducted shows that the outer solar system offers a variety of environments in which natural experiments in prebiotic organic synthesis must be taking place at the present time.

  1. Hikurangi Plateau: Crustal structure, rifted formation, and Gondwana subduction history

    NASA Astrophysics Data System (ADS)

    Davy, Bryan; Hoernle, Kaj; Werner, Reinhard

    2008-07-01

    Seismic reflection profiles across the Hikurangi Plateau Large Igneous Province and adjacent margins reveal the faulted volcanic basement and overlying Mesozoic-Cenozoic sedimentary units as well as the structure of the paleoconvergent Gondwana margin at the southern plateau limit. The Hikurangi Plateau crust can be traced 50-100 km southward beneath the Chatham Rise where subduction cessation timing and geometry are interpreted to be variable along the margin. A model fit of the Hikurangi Plateau back against the Manihiki Plateau aligns the Manihiki Scarp with the eastern margin of the Rekohu Embayment. Extensional and rotated block faults which formed during the breakup of the combined Manihiki-Hikurangi plateau are interpreted in seismic sections of the Hikurangi Plateau basement. Guyots and ridge-like seamounts which are widely scattered across the Hikurangi Plateau are interpreted to have formed at 99-89 Ma immediately following Hikurangi Plateau jamming of the Gondwana convergent margin at ˜100 Ma. Volcanism from this period cannot be separately resolved in the seismic reflection data from basement volcanism; hence seamount formation during Manihiki-Hikurangi Plateau emplacement and breakup (125-120 Ma) cannot be ruled out. Seismic reflection data and gravity modeling suggest the 20-Ma-old Hikurangi Plateau choked the Cretaceous Gondwana convergent margin within 5 Ma of entry. Subsequent uplift of the Chatham Rise and slab detachment has led to the deposition of a Mesozoic sedimentary unit that thins from ˜1 km thickness northward across the plateau. The contrast with the present Hikurangi Plateau subduction beneath North Island, New Zealand, suggests a possible buoyancy cutoff range for LIP subduction consistent with earlier modeling.

  2. Predicting the location of missing outer hair cells using the electrical signal recorded at the round window

    PubMed Central

    Chertoff, Mark E.; Earl, Brian R.; Diaz, Francisco J.; Sorensen, Janna L.; Thomas, Megan L. A.; Kamerer, Aryn M.; Peppi, Marcello

    2014-01-01

    The electrical signal recorded at the round window was used to estimate the location of missing outer hair cells. The cochlear response was recorded to a low frequency tone embedded in high-pass filtered noise conditions. Cochlear damage was created by either overexposure to frequency-specific tones or laser light. In animals with continuous damage along the partition, the amplitude of the cochlear response increased as the high-pass cutoff frequency increased, eventually reaching a plateau. The cochlear distance at the onset of the plateau correlated with the anatomical onset of outer hair cell loss. A mathematical model replicated the physiologic data but was limited to cases with continuous hair cell loss in the middle and basal turns. The neural contribution to the cochlear response was determined by recording the response before and after application of Ouabain. Application of Ouabain eliminated or reduced auditory neural activity from approximately two turns of the cochlea. The amplitude of the cochlear response was reduced for moderate signal levels with a limited effect at higher levels, indicating that the cochlear response was dominated by outer hair cell currents at high signal levels and neural potentials at low to moderate signal levels. PMID:25190395

  3. The crustal composition of the Falkland Plateau

    NASA Astrophysics Data System (ADS)

    Klemt, Claudia; Jokat, Wilfried

    2015-04-01

    The Falkland Islands are situated in the South Atlantic Ocean 500 km east of Patagonia, South America. The islands are part of the Falkland Plateau, which stretches eastward for more than 1500 km. A bathymetric high, the Maurice Ewing Bank, terminates the plateau in the east. Until Late Jurassic the Falkland Islands were part of Gondwana and were located adjacent to the east coast of South Africa. While the Falkland Islands and Maurice Ewing Bank are proved to be of continental composition, the nature and structure of the Falkland Plateau's basement in between is debatable. The first crustal model derived from sonobuoy data contradicts an only recently published 3D-gravity model. To enhance the understanding of Gondwana break-up considering timing, geometry and amount of volcanism, further knowledge about the structure and thickness of the crust is inevitable. During the ANT-XXIX/5 Polarstern cruise seismic refraction measurements were conducted using Ocean Bottom Seismometers (OBS) and Reftek land stations onshore of East Falkland. The OBS were deployed at 78 locations along an approximately 1500 km east-west stretching profile. For the western transect a P-wave velocity model is calculated using 2D-raytracing techniques. The results are presented in combination with potential field data showing the extension of the Falkland Islands basement, the continent-ocean transition zone and the crustal structure of the plateau. On the Falkland Plateau Basin sediment thickness is about 6 km with velocities ranging from 1.7 to 4.1 km/s in the upper part and about 4.7 km/s above basement. The crust is of oceanic composition with an igneous section that is considerably thicker than average oceanic crust (up to 17 km). The velocity structure in the upper crustal part is typical for layer 2 with a velocity gradient ranging from 5.4 km/s to 6.5 km/s and thicknesses between 1.5 km and 4 km. Layer 3 is about 14 km thick with a velocity gradient from 6.6 km/s to 7.6 km/s, which is

  4. 75 FR 61512 - Outer Continental Shelf Official Protraction Diagrams

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... Bureau of Ocean Energy Management, Regulation and Enforcement Outer Continental Shelf Official... Outer Continental Shelf Official Protraction Diagrams (OPDs) located within Atlantic Ocean areas, with... informational purposes only. Outer Continental Shelf Official Protraction Diagrams in the North Atlantic,...

  5. Insights into the crustal structure and magmatic evolution of the High and Western Plateau of the Manihiki Plateau, Central Pacific

    NASA Astrophysics Data System (ADS)

    Hochmuth, Katharina; Gohl, Karsten; Uenzelmann-Neben, Gabriele

    2014-05-01

    The Manihiki Plateau is a Large Igneous Province (LIP) located in the Central Pacific. It is assumed, that the formation of the Manihiki Plateau took place during the early Cretaceous in multiple volcanic stages as part of the "Super-LIP" Ontong-Java-Nui. The plateau consists of several sub-plateaus of which the Western Plateau und High Plateau are the largest. In addressing the plateau's magmatic evolutionary history, one of the key questions is whether all sub-plateaus experienced the same magmatic history or if distinct phases of igneous or tectonic processes led to its fragmentation. During the RV Sonne cruise SO-224 in 2012; we collected two deep crustal seismic refraction/wide-angle reflection lines, crossing the two main sub-plateaus. Modeling of P- and S-wave phases reveals the different crustal nature of both sub-plateaus. On the High Plateau, the 20 km thick crust is divided into four seismic units, interpreted to range from basaltic composition in the uppermost crust to peridotitic composition in the middle and lower crust. The Western Plateau on the other hand shows multiple rift structures and no indications of basalt flows. With a maximum of 17 km crustal thickness, the Western Plateau is also thinner than the High Plateau. The upper basement layers show relatively low P-wave velocities (3.0 - 5.0 km/s), which infers that on the Western Plateau these layers consist of volcanoclastic and carbonatic rocks rather than basaltic flow units. Later volcanic stages may be restricted to the High Plateau with a possible eastward trend in the center of volcanic activity. Extensive secondary volcanism does not seem to have occurred on the Western Plateau, and its later deformation is mainly caused by tectonic extension and rifting.

  6. Outer Hair Cell Electromotility and Otoacoustic Emissions*

    PubMed Central

    Brownell, William E.

    2009-01-01

    Outer hair cell electromotility is a rapid, force generating, length change in response to electrical stimulation. DC electrical pulses either elongate or shorten the cell and sinusoidal electrical stimulation results in mechanical oscillations at acoustic frequencies. The mechanism underlying outer hair cell electromotility is thought to be the origin of spontaneous otoacoustic emissions. The ability of the cell to change its length requires that it be mechanically flexible. At the same time the structural integrity of the organ of Corti requires that the cell possess considerable compressive rigidity along its major axis. Evolution appears to have arrived at novel solutions to the mechanical requirements imposed on the outer hair cell. Segregation of cytoskeletal elements in specific intracellular domains facilitates the rapid movements. Compressive strength is provided by a unique hydraulic skeleton in which a positive hydrostatic pressure in the cytoplasm stabilizes a flexible elastic cortex with circumferential tensile strength. Cell turgor is required in order that the pressure gradients associated with the electromotile response can be communicated to the ends of the cell. A loss in turgor leads to loss of outer hair cell electromotility. Concentrations of salicylate equivalent to those that abolish spontaneous otoacoustic emissions in patients weaken the outer hair cell’s hydraulic skeleton. There is a significant diminution in the electromotile response associated with the loss in cell turgor. Aspirin’s effect on outer hair cell electromotility attests to the role of the outer hair cell in generating otoacoustic emissions and demonstrates how their physiology can influence the propagation of otoacoustic emissions. PMID:2187727

  7. Mio-Pliocene morphotectonic evolution of the Iranian Plateau: from outward expansion to incision and excavation

    NASA Astrophysics Data System (ADS)

    Ballato, Paolo; Heidarzadeh, Ghasem; Zeilinger, Gerold; Ghassemi, Mohammad; Cifelli, Francesca; Mattei, Massimo; Hassanzadeh, Jamshid; Balling, Philipp; Dunkl, István; Sudo, Masafumi; Mulch, Andreas; Strecker, Manfred

    2015-04-01

    .5 and 12.5 Ma. At ~10.5 Ma an increase in sediment flux into the basin occurred as documented by an extensive progradation (> 50 km of distance) of conglomerates in the distal sectors of the basin. This event was followed by basin uplift and erosion with a shift of the basin depocenter toward the outer margin of the plateau (to the N and NE; Zanjan and Mianeh basins). There, sedimentation lasted until fluvial incision and basin excavation of sub-horizontal sediments started sometime during the last 4 Ma. Overall, our data suggest that sedimentation took place in a contiguous foreland-basin system, most likely triggered by thrust stacking and topographic loading in the interior of the plateau from ~17 Ma. The outward N to NE-directed propagation of the deformation fronts (< 10.5 Ma) excised parts of the foreland, incorporating new basin sectors into the orogenic plateau and compartmentalizing the foreland into a contractional basin and range topography. This implies that the IP developed during crustal shortening and thickening processes and that sometime after 10.5 Ma the northern IP had reached a lateral size similar to the modern one.

  8. Colorado Plateau magmatism and uplift by warming of heterogeneous lithosphere.

    PubMed

    Roy, Mousumi; Jordan, Thomas H; Pederson, Joel

    2009-06-18

    The forces that drove rock uplift of the low-relief, high-elevation, tectonically stable Colorado Plateau are the subject of long-standing debate. While the adjacent Basin and Range province and Rio Grande rift province underwent Cenozoic shortening followed by extension, the plateau experienced approximately 2 km of rock uplift without significant internal deformation. Here we propose that warming of the thicker, more iron-depleted Colorado Plateau lithosphere over 35-40 Myr following mid-Cenozoic removal of the Farallon plate from beneath North America is the primary mechanism driving rock uplift. In our model, conductive re-equilibration not only explains the rock uplift of the plateau, but also provides a robust geodynamic interpretation of observed contrasts between the Colorado Plateau margins and the plateau interior. In particular, the model matches the encroachment of Cenozoic magmatism from the margins towards the plateau interior at rates of 3-6 km Myr(-1) and is consistent with lower seismic velocities and more negative Bouguer gravity at the margins than in the plateau interior. We suggest that warming of heterogeneous lithosphere is a powerful mechanism for driving epeirogenic rock uplift of the Colorado Plateau and may be of general importance in plate-interior settings. PMID:19536263

  9. Spontaneous Regeneration of Human Photoreceptor Outer Segments

    PubMed Central

    Horton, Jonathan C.; Parker, Alicia B.; Botelho, James V.; Duncan, Jacque L.

    2015-01-01

    Photoreceptors are damaged in many common eye diseases, such as macular degeneration, retinal detachment, and retinitis pigmentosa. The development of methods to promote the repair or replacement of affected photoreceptors is a major goal of vision research. In this context, it would be useful to know whether photoreceptors are capable of undergoing some degree of spontaneous regeneration after injury. We report a subject who lost retinal function in a wide zone around the optic disc, giving rise to massive enlargement of the physiological blind spot. Imaging with an adaptive optics scanning laser ophthalmoscope (AOSLO) showed depletion of cone outer segments in the affected retina. A year later visual function had improved, with shrinkage of the enlarged blind spot. AOSLO imaging showed repopulation of cone outer segments, although their density remained below normal. There was a one-to-one match between sites of formerly missing outer segments and new outer segments that had appeared over the course of the year’s recovery. This correspondence provided direct morphological evidence that damaged cones are capable, under some circumstances, of generating new outer segments. PMID:26213154

  10. Addressing Climate Change Around the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Joswiak, Meri; Yao, Tandong; Joswiak, Daniel

    2013-08-01

    Most noted for the Himalayas, the Third Pole region encompasses several vast and varied mountain ranges, totaling 100,000 square kilometers of ice. For more than 4 years, Third Pole Environment (TPE) research program scientists and collaborators from around the globe have been racing to reveal, predict, and mediate the effects of global climate change on the mountainous region centered around the Tibetan Plateau, known as "Asia's water tower" for its expansive ice cover whose sensitive environment regulates water flow to the biggest rivers in Asia.

  11. Oceanic Plateau Overview and Look Ahead

    NASA Astrophysics Data System (ADS)

    Coffin, M. F.

    2011-12-01

    Oceanic plateaus result from fundamental processes in the Earth's interior, and have been implicated as instigators of major worldwide environmental changes. Although the plate tectonics paradigm successfully explains volcanic activity on the Earth's surface associated with seafloor spreading and plate subduction, it does not elucidate the massive flood volcanism that produces oceanic plateaus. Temporal correlations between flood basalts and environmental phenomena such as mass extinctions and oceanic anoxic events (OAEs) are well documented, yet the underlying mechanisms causing these global catastrophes are only beginning to be grasped. Focused investigations of oceanic plateaus have targeted the two largest features globally, the ~120 Ma Ontong Java Plateau (Pacific Ocean) and ~120-95 Ma Kerguelen Plateau/Broken Ridge (Indian Ocean), and the ~145-130 Ma Shatsky Rise (Pacific Ocean). These three features constitute the only oceanic plateaus where igneous basement has been drilled at more than one site. Multiple models - plume, bolide impact, and upwelling eclogite - have been proposed for Ontong Java's origin. The feature correlates temporally with OAE-1a, and interpretation of Sr, Os, and Pb isotopic systems during the time of OAE-1a points to a close linkage between the two, with CO2, Fe, and trace metal emissions from the massive magmatism potentially triggering the event. The Kerguelen Plateau/Broken Ridge is a composite feature that includes flood basalts, depleted mid-ocean ridge basalt (MORB)-related asthenosphere, and continental lithosphere. Models for the Shatsky Rise include mantle plume and fast seafloor spreading. Future studies of oceanic plateaus have the potential to transform our understanding of the Earth system through investigating: 1) magma (and hence mantle source) variability through times; 2) the nature of melting anomalies, i.e., compositional vs. thermal, that produce oceanic plateaus; 3) the precise durations of oceanic plateau events

  12. Going beyond Career Plateau: Using Professional Plateau To Account for Work Outcomes.

    ERIC Educational Resources Information Center

    Lee, Patrick Chang Boon

    2003-01-01

    Survey responses from 170 of 300 engineers working in Singapore revealed that significant variance in career satisfaction, job satisfaction, and turnover intentions was accounted for by professional plateau, the point at which individuals find their jobs unchallenging with few opportunities for professional development. (Contains 33 references.)…

  13. Baseline Microstructural Characterization of Outer 3013 Containers

    SciTech Connect

    Zapp, Phillip E.; Dunn, Kerry A

    2005-07-31

    Three DOE Standard 3013 outer storage containers were examined to characterize the microstructure of the type 316L stainless steel material of construction. Two of the containers were closure-welded yielding production-quality outer 3013 containers; the third examined container was not closed. Optical metallography and Knoop microhardness measurements were performed to establish a baseline characterization that will support future destructive examinations of 3013 outer containers in the storage inventory. Metallography revealed the microstructural features typical of this austenitic stainless steel as it is formed and welded. The grains were equiaxed with evident annealing twins. Flow lines were prominent in the forming directions of the cylindrical body and flat lids and bottom caps. No adverse indications were seen. Microhardness values, although widely varying, were consistent with annealed austenitic stainless steel. The data gathered as part of this characterization will be used as a baseline for the destructive examination of 3013 containers removed from the storage inventory.

  14. Origin of the Outer Solar System

    NASA Technical Reports Server (NTRS)

    Holman, Matthew J. (Principal Investigator); Boyce, Joseph (Technical Monitor)

    2003-01-01

    Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; (2) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; (5) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

  15. Chasing shadows in the outer solar system

    NASA Astrophysics Data System (ADS)

    Bianco, Federica

    The characteristics of the populations of objects that inhabit the outer solar system carry the fingerprint of the processes that governed the formation and evolution of the solar system. Occultation surveys push the limit of observation into the very small and distant outer solar system objects, allowing us to set constraints on the structure of the Kuiper belt, Scattered disk and Sedna populations. I collected, reduced, and analyzed vast datasets looking for occultations of stars by outer solar system objects, both working with the Taiwanese American Occultation Survey (TAOS) collaboration and leading the MMT/Megacam occultation effort. Having found no such events in my data, I was able to place upper limits on the Kuiper belt, scattered disk and Sedna population. These limits and their derivation are described here.

  16. Outer planet probe cost estimates: First impressions

    NASA Technical Reports Server (NTRS)

    Niehoff, J.

    1974-01-01

    An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation.

  17. Ptolemy's treatment of the outer planets

    NASA Astrophysics Data System (ADS)

    Duke, Dennis

    2005-01-01

    The purpose of this paper is to investigate whether for the outer planets Ptolemy followed his otherwise consistent custom of describing a scenario that did not happen as he says, or whether, at least for the outer planets, he left us a more accurate rendition of events. The detailed reconstructions of Ptolemy's calculations that follow show that, at least in the Almagest, Ptolemy is a writer with consistent habits when it comes to observations. We begin by reviewing, with minimal editorial comment, Ptolemy's calculations for each planet.

  18. Titan exploration in the Outer Planets Program

    NASA Astrophysics Data System (ADS)

    Niebur, Curt

    2010-04-01

    Although the next NASA Outer Planets Flagship Mission is expected to be directed to the Jovian system focusing on Europa, Titan after Cassini-Huygens remains a high priority target of interest due to its parallels with the Earth (including weather) and potential for astrobiology. This talk will discuss the possibilities for future robotic exploration of Titan in the context of the NASA Outer Planets Program, including Discovery and New Frontiers-class spacecraft, and the necessary precursor activities to missions such as technology development.

  19. Cochlear amplification, outer hair cells and prestin

    PubMed Central

    Dallos, Peter

    2008-01-01

    Mechanical amplification of acoustic signals is apparently a common feature of vertebrate auditory organs. In non-mammalian vertebrates amplification is produced by stereociliary processes, related to the mechanotransducer channel complex and probably to the phenomenon of fast adaptation. The extended frequency range of the mammalian cochlea has likely co-evolved with a novel hair cell type, the outer hair cell and its constituent membrane protein, prestin. Cylindrical outer hair cells are motile and their somatic length changes are voltage driven and powered by prestin. One of the central outstanding problems in mammalian cochlear neurobiology is the relation between the two amplification processes. PMID:18809494

  20. Abnormally high formation pressures, Potwar Plateau, Pakistan

    USGS Publications Warehouse

    Law, B.E.; Shah, S.H.A.; Malik, M.A.

    1998-01-01

    Abnormally high formation pressures in the Potwar Plateau of north-central Pakistan are major obstacles to oil and gas exploration. Severe drilling problems associated with high pressures have, in some cases, prevented adequate evaluation of reservoirs and significantly increased drilling costs. Previous investigations of abnormal pressure in the Potwar Plateau have only identified abnormal pressures in Neogene rocks. We have identified two distinct pressure regimes in this Himalayan foreland fold and thrust belt basin: one in Neogene rocks and another in pre-Neogene rocks. Pore pressures in Neogene rocks are as high as lithostatic and are interpreted to be due to tectonic compression and compaction disequilibrium associated with high rates of sedimentation. Pore pressure gradients in pre-Neogene rocks are generally less than those in Neogene rocks, commonly ranging from 0.5 to 0.7 psi/ft (11.3 to 15.8 kPa/m) and are most likely due to a combination of tectonic compression and hydrocarbon generation. The top of abnormally high pressure is highly variable and doesn't appear to be related to any specific lithologic seal. Consequently, attempts to predict the depth to the top of overpressure prior to drilling are precluded.

  1. Episodic karstification, Edwards Plateau, central Texas

    SciTech Connect

    Kastning, E.H.

    1985-01-01

    The Edwards Plateau and Llano Basin of central Texas form one of the largest contiguous regions of karst in North America (>80,000 km/sup 2/). Solutional phenomena show that several major episodes of karstification are documentable from late Cambrian to Holocene. Relict landforms representing intervals of solutional activity correlate well with the accepted geomorphic chronology for central Texas. Secondary porosity are vertically controlled by lithology, topographic incision of streams, position of the potentiometric surface, and attitude of bedding. Areally, development of karst is strongly influenced by the extent, density, and orientation of fractures and by hydrodynamic characteristics such as points of recharge and discharge, degree of integration of groundwater flow paths, and hydraulic gradients. Early episodes of karstification correspond to intervals of subaerial exposure of carbonate rocks during marine regression or following regional uplift. Paleokarst is prevalent in the Paleozoic and Mesozoic sequences. Infilled dolines and solution-collapse breccias have been exhumed by extensive regional denudation during the Cenozoic Era. Subaerial conditions during the middle Cretaceous account for infilled solutional cavities within lower Cretaceous carbonate beds. The most extensive karstification began with regional uplift in the early Miocene. Enhanced relief along the Balcones escarpment promoted incision of streams, lowering of water tables, steepened hydraulic gradients, and increases in discharge. Caves at various-elevations attest to sequential dissection of the plateau during the late Quaternary.

  2. Prevention of the Outer Space Weaponization

    NASA Astrophysics Data System (ADS)

    Zhukov, Gennady P.

    2002-01-01

    9 states. The satellites of various functions (early warning, communication, data acquisition, reconnaissance and navigation) were actively used and continue to be used with the purposes of raising efficiency of ground armed forces, especially in fight against international terrorism. At the same time such satellites are not a weapon in the sense of that word since they do not create the threats of armed attack in outer space or from outer space. Moreover, they promote maintaining of stability in the international relations. For this reason the reconnaissance and data acquisition satellites used for the verification of observance by States of the arms limitation agreements are under international protection as national technical means of the control. Similar protection is enjoyed by the early warning satellites. With the help of space communication facilities the more reliable operative connection of the statesmen is organized in the strained situations. By this way the probability of making of the incorrect retaliatory decisions in critical political situations is reduced. At the same time it's necessary to take into consideration that the activities of such satellite systems are tightly connected with ground armed forces of the states. the earth, what from the point of view of international law may be qualified as establishing a partial demilitarization regime in outer space. After the prohibition of anti-satellite weapons (ASAT) and anti-satellite (ASAT) weapons it will be possible to speak about establishing of an international legal regime of complete demilitarization in outer space eliminating any kinds of weapon from outer space. in a peaceful time. weaponization.The main task of this paper is to analyze and to discuss the present binding regime of the outer space deweaponization and particular measures on consolidation and strengthening of this regime. agreements of the Russian Federation and the USA into multilateral Treaties. Such "immunity" would cover

  3. Fossil snail shells tell story about Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wendel, JoAnna

    2014-09-01

    Ancient and modern snail shells have given scientists a unique look at the evolution of the Tibetan Plateau, confirming that parts of the plateau have actually lost elevation over time, despite its immense height. A new paper detailing the research was published on 29 August in the Geological Society of America Bulletin (doi:10.1130/B31000.1).

  4. Plateauing and Its Consequences for Educators and Educational Organizations.

    ERIC Educational Resources Information Center

    Milstein, Mike

    Plateauing is an individual's conviction that continued progress is impossible. This conviction occurs as a consequence of long periods of occupational stability. When practitioners doubt the probability of promotion or the importance of their work and find their work to be boring and redundant, they are exhibiting symptoms of plateauing rather…

  5. Thrusting on the Tibetan plateau within the last 5 Ma

    NASA Technical Reports Server (NTRS)

    Burke, Kevin; Lucas, Lynette

    1989-01-01

    The Lunpola basin, in the middle of the Tibetan plateau, contains about 4 km of nonmarine sediments deposited since early Cenozoic times. This remarkable structure, localized in the Bangong-Nujiang suture zone, has much to teach about how the plateau has developed. The strong evidence for young compression in the basin is emphasized.

  6. The magnetospheres of the outer planets

    SciTech Connect

    Mcnutt, R.L., Jr. )

    1991-01-01

    Research on the magnetospheres of all of the outer planets including Jupiter, Uranus, Neptune, and Pluto is reviewed for the 1987-1990 time period. Particular attention is given to magnetospheric structure, plasma transport, Jovian aurora, Io and the plasma torus, Titan and its magnetospheric interactions, rings and dusty plasmas, magnetospheric convection, and satellite interactions.

  7. Assembly Platform For Use In Outer Space

    NASA Technical Reports Server (NTRS)

    Rao, Niranjan S.; Buddington, Patricia A.

    1995-01-01

    Report describes conceptual platform or framework for use in assembling other structures and spacecraft in outer space. Consists of three fixed structural beams comprising central beam and two cross beams. Robotic manipulators spaced apart on platform to provide telerobotic operation of platform by either space-station or ground crews. Platform and attached vehicles function synergistically to achieve maximum performance for intended purposes.

  8. The processing of materials in outer space

    NASA Technical Reports Server (NTRS)

    Gelles, S. H.; Colling, E. W.

    1977-01-01

    Zero-gravity environment may lead to fabrication of new and improved materials. According to comprehensive study of application of this promising technology to superconducting and electrical contact materials, outer space processing could improve microstructure and homogeneity of many single and multicomponent systems formed from solidification of fluid phases. New structures that are impossible to form terrestrially may also be accessible in space environment.

  9. BIOREACTOR DESIGN - OUTER LOOP LANDFILL, LOUISVILLE, KY

    EPA Science Inventory

    Bioreactor field demonstration projects are underway at the Outer Loop Landfill in Louisville, KY, USA. The research effort is a cooperative research effort between US EPA and Waste Management Inc. Two primary kinds of municipal waste bioreactors are under study at this site. ...

  10. Ground Based Studies of the Outer Planets

    NASA Technical Reports Server (NTRS)

    Trafton, Laurence M.

    2005-01-01

    This report covers progress to date under this grant on our continuing program to conduct ground based studies of the outer solar system planets and satellites, with emphasis on spectroscopy and atmospheric phenomena. The research continues under our new PAST grant, NNG04G131G beginning 5/1/2004. The original period of performance of the subject grant was 3/1/2001 to 2/28/2004, but was extended one year at no cost. Although there is some overlap in the scientific projects conducted during the extended year with those of the new grant, this report is confined to the portion of the work funded under NAG5-10435. The primary goals for this grant period were a comparative study of outer planet thermospheres/ionospheres near solar maximum, extended to the mid-IR, and the investigation of molecular dimers in outer solar system atmospheres. This project supports NASA's planned space missions, Jupiter Polar Orbiter, outer Planet Microprobes, and the recent Cassini flyby of Jupiter. It also supports the OSS strategic plan themes, The Exploration of the Solar System and The Sun-Earth Connection/ Understanding comparative planetary space environments.

  11. THE ORBITS OF THE OUTER URANIAN SATELLITES

    SciTech Connect

    Brozovic, M.; Jacobson, R. A.

    2009-04-15

    We report on the numerically integrated orbits for the nine outer Uranian satellites. The orbits are calculated based on fits to the astrometric observations for the period from 1984 to 2006. The results include the state vectors, post-fit residuals, and mean orbital elements. We also assess the accuracy of the orbital fits and discuss the need for future measurements.

  12. Tower mast of precipitation over the central Tibetan Plateau summer

    NASA Astrophysics Data System (ADS)

    Fu, Yunfei; Liu, Guosheng; Wu, Guoxiong; Yu, Rucong; Xu, Youping; Wang, Yu; Li, Rui; Liu, Qi

    2006-03-01

    Over the Tibetan Plateau, solar heating often produces strong convective instability in the atmosphere. Using 3 years (1998-2000) of Tropical Rainfall Measuring Mission (TRMM) precipitation radar data, our investigations revealed a tower mast shape of precipitation over the Plateau in both height-longitude and height-latitude cross-sections. High rain rate center over the Plateau is located above 6km as a tower penetrating into the mid-troposphere against the nearby background, implying a unique latent heating source injecting directly to the middle atmosphere. Results indicate that there are more isolated rain cells over the Plateau than its nearby regions, and the strongest diurnal cycle of rainfall existing over the Plateau with a peak around 1600 and a valley around 0500 local time, indicating the dominance of convective clouds caused by solar heating. It is also found that the TRMM algorithm might have misclassified weak convections as stratiform rains.

  13. Extension of the Yellowstone plateau, eastern Snake River Plain, and Owyhee plateau

    SciTech Connect

    Rodgers, D.W.; Hackett, W.R.; Ore, H.T. )

    1990-11-01

    Formation of the late Cenozoic volcanic province comprising the Owyhee plateau, eastern Snake River Plain, and Yellowstone plateau has been accompanied by east-northeast-directed crustal extension. A new vector of 45 mm/yr, N56{degree}E for the migration of silicic volcanism across the volcanic province is calculated. If migration of volcanism reflects west-southwest continental drift over a mantle plume, a zone of crustal extension must separate the volcanic province from the more slowly moving North American craton. Space-time relations of basin fill in the adjacent Basin and Range province provide evidence for a zone of extension, about 125 km wide, coincident with and east of coeval silicic volcanism. Since 16 Ma, the zone of extension has migrated along with silicic volcanism, maintaining its position between the province and the unextended craton.

  14. Loess Plateau storage of Northeastern Tibetan Plateau-derived Yellow River sediment

    PubMed Central

    Nie, Junsheng; Stevens, Thomas; Rittner, Martin; Stockli, Daniel; Garzanti, Eduardo; Limonta, Mara; Bird, Anna; Andò, Sergio; Vermeesch, Pieter; Saylor, Joel; Lu, Huayu; Breecker, Daniel; Hu, Xiaofei; Liu, Shanpin; Resentini, Alberto; Vezzoli, Giovanni; Peng, Wenbin; Carter, Andrew; Ji, Shunchuan; Pan, Baotian

    2015-01-01

    Marine accumulations of terrigenous sediment are widely assumed to accurately record climatic- and tectonic-controlled mountain denudation and play an important role in understanding late Cenozoic mountain uplift and global cooling. Underpinning this is the assumption that the majority of sediment eroded from hinterland orogenic belts is transported to and ultimately stored in marine basins with little lag between erosion and deposition. Here we use a detailed and multi-technique sedimentary provenance dataset from the Yellow River to show that substantial amounts of sediment eroded from Northeast Tibet and carried by the river's upper reach are stored in the Chinese Loess Plateau and the western Mu Us desert. This finding revises our understanding of the origin of the Chinese Loess Plateau and provides a potential solution for mismatches between late Cenozoic terrestrial sedimentation and marine geochemistry records, as well as between global CO2 and erosion records. PMID:26449321

  15. Loess Plateau storage of Northeastern Tibetan Plateau-derived Yellow River sediment.

    PubMed

    Nie, Junsheng; Stevens, Thomas; Rittner, Martin; Stockli, Daniel; Garzanti, Eduardo; Limonta, Mara; Bird, Anna; Andò, Sergio; Vermeesch, Pieter; Saylor, Joel; Lu, Huayu; Breecker, Daniel; Hu, Xiaofei; Liu, Shanpin; Resentini, Alberto; Vezzoli, Giovanni; Peng, Wenbin; Carter, Andrew; Ji, Shunchuan; Pan, Baotian

    2015-01-01

    Marine accumulations of terrigenous sediment are widely assumed to accurately record climatic- and tectonic-controlled mountain denudation and play an important role in understanding late Cenozoic mountain uplift and global cooling. Underpinning this is the assumption that the majority of sediment eroded from hinterland orogenic belts is transported to and ultimately stored in marine basins with little lag between erosion and deposition. Here we use a detailed and multi-technique sedimentary provenance dataset from the Yellow River to show that substantial amounts of sediment eroded from Northeast Tibet and carried by the river's upper reach are stored in the Chinese Loess Plateau and the western Mu Us desert. This finding revises our understanding of the origin of the Chinese Loess Plateau and provides a potential solution for mismatches between late Cenozoic terrestrial sedimentation and marine geochemistry records, as well as between global CO2 and erosion records. PMID:26449321

  16. Ecological aspects of the Jos Plateau, Nigeria*

    PubMed Central

    Lee, V. H.

    1972-01-01

    The Jos Plateau has an area of about 6 700 km2, lies at 1 280 m above sea level, and contains approximately 1 million inhabitants. Annual rainfall averaged 137 cm in the period 1965-68; in 1969 rainfall totalled 170 cm and lasted for a month longer than usual. The rural population is engaged in agriculture, tin mining, and cattle grazing. Animal life consists chiefly of domestic species; there are few large wild animals. Wild primates are apparently rare, although baboons and red patas monkeys are sometimes seen. Tree cover is restricted to small patches along streams and some hillsides; there are euphorbia hedges and scattered trees in rural communities and along roadsides. PMID:4538036

  17. Logarithmic correlations in quantum Hall plateau transitions

    NASA Astrophysics Data System (ADS)

    Vasseur, Romain

    2015-07-01

    The critical behavior of quantum Hall transitions in two-dimensional disordered electronic systems can be described by a class of complicated, nonunitary conformal field theories with logarithmic correlations. The nature and the physical origin of these logarithmic correlation functions remain, however, mysterious. Using the replica trick and the underlying symmetries of these quantum critical points, we show here how to construct nonperturbatively disorder-averaged observables in terms of Green's functions that scale logarithmically at criticality. In the case of the spin quantum Hall transition, which may occur in disordered superconductors with spin-rotation symmetry and broken time reversal invariance, we argue that our results are compatible with an alternative approach based on supersymmetry. The generalization to the integer quantum Hall plateau transition is also discussed.

  18. Aeolian Sediments on the northeastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Stauch, G.; Lehmkuhl, F.

    2013-12-01

    The timing and spatial distribution of aeolian sediments on the northeastern Tibetan Plateau have gained increasing interest during the last decades. The formation of the aeolian deposits is often related to cold and dry climate conditions. However, further important parameters are the local geomorphological setting and sediment availability in the source areas of the sediments. Aeolian sediments including loess, sandy loess and sands are widespread in the catchment of the Donggi Cona on the northeastern Tibetan Plateau at around 4000 m asl. Detailed geomorphological mapping of the deposits and geochemical analyses of the sediments revealed varying sources throughout the Holocene. The timing of the sediment deposition is based on 43 OSL (optical stimulated luminescence) ages. Several phases of enhanced aeolian deposition took place during the Holocene. The accumulation of aeolian sands lasted from 10.5 until 7 ka. The main source area of these sands was a large alluvial fan. Parallel to the formation of the dunes loess was deposited on the adjacent slopes from 10.5 until 7.5 ka. These sediments most probably originate in the nearby Qaidam Basin. In contrast to the general linkage of aeolian sediments to dryer climate conditions formation of these aeolian deposits is related to wetter conditions due to a strengthening of the Asian Summer Monsoons. The wetter climate enhanced the trapping and continuous fixation of the aeolian sediments by vegetation. With the further strengthening of the Monsoon fluvial processes eroded the aeolian deposits at least until 6 ka. From about 3 ka to the present a reactivation of aeolian sands and the formation of new dunes took place. This reactivation is related to drier conditions on the north-eastern Tibetan Plateau. Additionally, an increased human influence might have enhanced the aeolian activity. Similar phases of enhanced aeolian activity have been documented in more than 170 available OSL ages from loess and aeolian sands in

  19. Plateau inflation in SUGRA-MSSM

    NASA Astrophysics Data System (ADS)

    Chakravarty, Girish Kumar; Gupta, Gaveshna; Lambiase, Gaetano; Mohanty, Subhendra

    2016-09-01

    We explored a Higgs inflationary scenario in the SUGRA embedding of the MSSM in Einstein frame where the inflaton is contained in the SU (2) Higgs doublet. We include all higher order non-renormalizable terms to the MSSM superpotential and an appropriate Kähler potential which can provide slow-roll inflaton potential in the D-flat direction. In this model, a plateau-like inflation potential can be obtained if the imaginary part of the neutral Higgs acts as the inflaton. The inflationary predictions of this model are consistent with the latest CMB observations. The model represents a successful Higgs inflation scenario in the context of Supergravity and it is compatible with Minimal Supersymmetric extension of the Standard Model.

  20. Geochemical Evolution of the Hikurangi Oceanic Plateau, New Zealand

    NASA Astrophysics Data System (ADS)

    Hoernle, K.; Hauff, F.; Werner, R.; Mortimer, N.; van den Bogaard, P.; Geldmacher, J.; Garbe-Schoenberg, D.

    2004-12-01

    The Hikurangi oceanic plateau or large igneous province (LIP), located east of the North Island of New Zealand, covers an area of 350,000 km3 and is located at a depth of 2,500-3,500 b.s.l. The Hikurangi plateau was possibly connected to the Manihiki LIP (now located 3000 km to the north) but may have been separated by Cretaceous seafloor spreading at the Osbourn Trough (Billen and Stock, 2000, J. Geophys. Res., 106, 13481-13489). Therefore it may have formed part of the "greater Ontong Java Plateau event" (Coffin and Eldholm, Geology, 21, 515-51), the largest magmatic event preserved on Earth. During the R/V Sonne SO168 ZEALANDIA cruise, 77 dredge hauls containing igneous samples were recovered from the Hikurangi Plateau. Volcanic rocks were obtained from 1) the plateau basement along the 1 km high Rapuhia Scarp, 2) large guyot-type seamounts within the plateau, and 3) ridge-type seamounts associated with rifting of the NE plateau margin (Hoernle et al., 2004, EOS). The recovered plateau rocks range from basalts, dolerites and gabbros with tholeiitic and alkali basaltic to trachybasaltic compositions. The seamount volcanic rocks have more Si-undersaturated compositions than the plateau rocks and range from alkali basalts through mugearites to basanites through tephrites to nephelinites. The plateau basement rocks have flat rare earth element (REE) patterns similar to enriched mid-ocean-ridge basalt (MORB) and basement rocks from other oceanic LIPs, such as Manihiki, Ontong-Java and the Caribbean. The late-stage seamount lavas show enrichment in the light REE and all strongly to moderately incompatible elements, having incompatible element characteristics similar to the HIMU (high time-integrated U/Pb) component in ocean island basalts (OIB). Although the Pb isotopic composition has been extensively effected by seawater alteration, the freshest samples have enriched (EM-type) Sr-Nd-Pb isotopic compositions similar to Ontong-Java and Manihiki basement rocks

  1. The deep structure of Venusian plateau highlands

    NASA Technical Reports Server (NTRS)

    Grimm, Robert E.

    1994-01-01

    Magellan gravity data confirm that several of the large, tectonically deformed, plateau-like highlands on venus are shallowly compensated, most likely by crustal thickness variations. Apparent depths of isostatic compensation, computed in the spatial domain, range from 30 to 50 km for Alpha, Tellus, Ovda, and Thetis Regiones. Using a two-layer model for isostatic compensation, Alpha, Tellus, and Ovda are best represented as nearly completely compensated in crust that is regionally 20-40 km thick around these highlands, with little contribution from deeper mantle sources. In contrast to these three areas, a stronger regional gravity high associated with Thetis requires a significant upper mantle component to compensation. This is evident in the spectral admittance as a pronounced deep, long-wavelength anomaly. In the two-layer isostatic model, a broad, deeply compensated upland underlies a shallowly compensated central block of Thetis. If this deep component is interpreted as a thermal anomaly, the loci of maximum upwelling agree well with sites of recent extension. The plateau highlands are thus physiographically and isostatically equivalent to terrestrial continents, though probably not compositionally. They also share the record of a long tectonic history. The large regional gravity anomaly of Thetis indicates that active mantle proceses continue even beneath some areas (tessera) thought to be a relic of a former geological regime. The excellent agreement of modeled crustal thicknesses around Alpha, Tellus, and Ovda Regiones suggests that 20-40 km is a representative global value for the plains. Such a crust is thicker than previously estimated and about twice as thick as the expected thickness of crust produced at venusian spreading centers

  2. Surgical options for posterior tibial plateau fracture

    PubMed Central

    Chen, Hongwei; Wu, Lijun

    2015-01-01

    Objective: To investigate surgical methods and clinical effectiveness of posteromedial and posterolateral approaches for the posterior tibial plateau fracture. Method: 21 cases who received surgery through posterior approaches for the treatment of posterior tibial plateau fractures (PTPFs) were included. Results: 21 cases were subject to follow-up for 12-24 months (an average of 16.2 months). No cases developed incision inflammation, neurovascular injury, internal fixation loosening and breakage. All fractures were healed. No cases developed knee varus and valgus deformity and fracture dislocation. After surgery, Rasmussen score for knee joint functions was 13-30 points (a mean of 24.2). The results were excellent in 12 cases, good in 7 cases and fair in 2 cases. The percentage of excellent and good results was 90.5%. Rasmussen radiology score was 10-18 points (a mean of 15.6 points). The results were excellent in 13 cases, good in 7 cases and fair in 1 cases. The percentage of excellent and good results was 95.2%. 1 case had significant limited range of knee flexion and extension, which was improved after phase II release under arthroscopy combined with function exercise. 2 cases developed traumatic arthritis, which was relieved after intra-articular injection with sodium hyaluronate and oral nonsteroidal anti-inflammatory drug. Conclusion: The posteromedial and posterolateral approaches for PTPF is good for reduction and fixation of PTPF. The approaches have benefits such as clear exposure, convenient placement of internal fixation, less trauma and good clinical outcome. PMID:26885086

  3. Investigation of plateau basin crustal structures and thickening mechanisms in the northeastern margin of the Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Jia, Shixu; Xu, Zhaofan; Liu, Zhi; Zhang, Jianshi; Liu, Baofeng; Lin, Jiyan; Guo, Wenbin

    2012-12-01

    This paper uses deep seismic sounding (DSS) data to contrast and analyze the crustal structures of three plateau basins (Songpan-Garze, Qaidam, Longzhong) in the northeastern margin of the Qinghai-Xizang (Tibetan) plateau, as well as two stable cratonic basins (Ordos, Sichuan) in its peripheral areas. Plateau basin crustal structures, lithological variations and crustal thickening mechanisms were investigated. The results show that, compared to the peripheral stable cratonic basins, the crystalline crusts of plateau basins in the northeastern margin are up to 10-15 km thicker, and the relative medium velocity difference is about 5% less. The medium velocity change in crustal layers of plateau basin indicates that the upper crust undergoes brittle deformation, whereas the lower crust deforms plastically with low velocity. The middle crust shows a brittle-to-plastic transition zone in this region. Thickening in the lower crust (about 5-10 km), and rheological characteristics that show low-medium velocity (relatively reduced by 7%), suggest that crustal thickening mainly takes place in lower crust in the northeastern margin of the Tibetan plateau. The crust along the northeastern margin shows evidence of wholesale block movement, and crustal shortening and thickening seem to be the main deformation features of this region. The GPS data show that the block motion modes and crustal thickening in the Tibetan plateau is closely related to the peripheral tectonic stress field and motion direction of the Indian plate. The Mani-Yushu-Xianshuihe fold belt along the boundary between the Qiangtang block and the Bayan Har block divides the different plateau thickening tectonic environments into the middle-western plateau, the northeastern margin and the southeastern plateau.

  4. Eocene Tibetan plateau remnants preserved in the northwest Himalaya

    NASA Astrophysics Data System (ADS)

    van der Beek, Peter; van Melle, Jérémie; Guillot, Stéphane; Pêcher, Arnaud; Reiners, Peter W.; Nicolescu, Stefan; Latif, Mohammad

    2009-05-01

    The northwest Himalaya shows strongly contrasting relief. Deeply incised mountain ranges that are characterized by extremely rapid exhumation and some of the highest peaks in the world are in contrast with high-elevation, low-relief areas such as the Deosai plateau in northern Pakistan, which lies at an altitude of 4,000m. The origin and evolution of such plateau regions at the convergence of the most active continental collision in the world remain elusive. Here we report low-temperature thermochronology data from the Deosai plateau and use thermal history modelling to show that the plateau has undergone continuous slow denudation at rates below 250mMyr-1 for the past 35Myr at least. This finding suggests tectonic and morphologic stability of the plateau since at least Eocene times, only 15-20Myr after the onset of the India-Asia collision. Our work contradicts the hypothesis that widespread low-relief surfaces in the northwest Himalaya result from efficient kilometre-scale glacial erosion during Quaternary times. We show that similarly stable surfaces exist throughout the entire northwest Himalaya and share common morphologic characteristics and denudation histories, which are comparable to those of the western Tibetan plateau. Our results suggest that these surfaces are preserved remnants of an Eocene southwestern Tibetan plateau that was more extensive than today.

  5. Ion Composition in the Outer Ionosphere

    NASA Astrophysics Data System (ADS)

    Triskova, L.; Truhlik, V.; Smilauer, J.

    The recently developed global model of relative ion composition in the outer ionosphere has been used to construct a model of absolute ion densities. Data from the ACTIVE mission for maximum of the solar cycle 22 were completed by available data from the AE satellites from the minimum of solar cycle 21. The total ion concentration has been taken from the Retarding Potential Analyzers working onboard the mentioned satellites. The global model comprises submodels for three altitude levels at low solar activity and four altitude levels at high solar activity. Attention is paid to the manifestation of solar activity in behaviour of individual ion species. For medium solar activity conditions data measured onboard the OGO-6 were used (maximum of the low cycle 20). For interpolation between submodels, functions alternative to the Booker's ones are searched. Merging of the IRI bottom side data into the outer ionosphere model is shown.

  6. Cryovolcanism in the outer solar system

    USGS Publications Warehouse

    Geissler, Paul E.

    2015-01-01

    Cryovolcanism is defined as the extrusion of liquids and vapors of materials that would be frozen solid at the planetary surface temperatures of the icy bodies of the outer solar system. Active cryovolcanism is now known to occur on Saturn's moon Enceladus and on Neptune's moon Triton and is suspected on Jupiter's moon Europa, while evidence for past cryovolcanic activity is widespread throughout the outer solar system. This chapter examines the mechanisms and manifestations of cryovolcanism, beginning with a review of the materials that make up these unusual ‘‘magmas’’ and the means by which they might erupt and concluding with a volcanologist's tour of the farthest reaches of the solar system.

  7. Outer crust of nonaccreting cold neutron stars

    NASA Astrophysics Data System (ADS)

    Rüster, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Jürgen

    2006-03-01

    The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars.

  8. Outer crust of nonaccreting cold neutron stars

    SciTech Connect

    Ruester, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Juergen

    2006-03-15

    The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars.

  9. The DarkSide-50 outer detectors

    NASA Astrophysics Data System (ADS)

    Westerdale, S.; Agnes, P.; Agostino, L.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Arisaka, K.; Back, H. O.; Baldin, B.; Biery, K.; Bonfini, G.; Bossa, M.; Bottino, B.; Brigatti, A.; Brodsky, J.; Budano, F.; Bussino, S.; Cadeddu, M.; Cadonati, L.; Cadoni, M.; Calaprice, F.; Canci, N.; Candela, A.; Cao, H.; Cariello, M.; Carlini, M.; Catalanotti, S.; Cavalcante, P.; Chepurnov, A.; Cocco, A. G.; Covone, G.; D’Angelo, D.; D’Incecco, M.; Davini, S.; De Cecco, S.; De Deo, M.; De Vincenzi, M.; Derbin, A.; Devoto, A.; Di Eusanio, F.; Di Pietro, G.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Foster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Giganti, C.; Goretti, A. M.; Granato, F.; Grandi, L.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B. R.; Herner, K. R.; Hungerford, E. V.; Aldo, Ianni; Andrea, Ianni; James, I.; Jollet, C.; Keeter, K.; Kendziora, C. L.; Kobychev, V.; Koh, G.; Korablev, D.; Korga, G.; Kubankin, A.; Li, X.; Lissia, M.; Lombardi, P.; Luitz, S.; Ma, Y.; Machulin, I. N.; Mandarano, A.; Mari, S. M.; Maricic, J.; Marini, L.; Martoff, C. J.; Meregaglia, A.; Meyers, P. D.; Miletic, T.; Milincic, R.; Montanari, D.; Monte, A.; Montuschi, M.; Monzani, M. E.; Mosteiro, P.; Mount, B. J.; Muratova, V. N.; Musico, P.; Napolitano, J.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Parmeggiano, S.; Pelczar, K.; Pelliccia, N.; Perasso, S.; Pocar, A.; Pordes, S.; Pugachev, D. A.; Qian, H.; Randle, K.; Ranucci, G.; Razeto, A.; Reinhold, B.; Renshaw, A. L.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, S. D.; Sablone, D.; Saggese, P.; Saldanha, R.; Sands, W.; Sangiorgio, S.; Savarese, C.; Segreto, E.; Semenov, D. A.; Shields, E.; Singh, P. N.; DSkorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Stanford, C.; Suvorov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Trinchese, P.; Unzhakov, E. V.; Vishneva, A.; Vogelaar, B.; Wada, M.; Walker, S.; Wang, H.; Wang, Y.; Watson, A. W.; Wilhelmi, J.; Wojcik, M. M.; Xiang, X.; Xu, J.; Yang, C.; Yoo, J.; Zavatarelli, S.; Zec, A.; Zhong, W.; Zhu, C.; Zuzel, G.; The DarkSide Collaboration

    2016-05-01

    DarkSide-50 is a dark matter detection experiment searching for Weakly Interacting Massive Particles (WIMPs), in Gran Sasso National Laboratory. For experiments like DarkSide-50, neutrons are one of the primary backgrounds that can mimic WIMP signals. The experiment consists of three nested detectors: a liquid argon time projection chamber surrounded by two outer detectors. The outermost detector is a 10 m by 11 m cylindrical water Cherenkov detector with 80 PMTs, designed to provide shielding and muon vetoing. Inside the water Cherenkov detector is the 4 m diameter spherical boron-loaded liquid scintillator veto, with a cocktail of pseudocumene, trimethyl borate, and PPO wavelength shifter, designed to provide shielding, neutron vetoing, and in situ measurements of the TPC backgrounds. We present design and performance details of the DarkSide-50 outer detectors.

  10. Boundary layers of the earth's outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Eastman, T. E.; Frank, L. A.

    1984-01-01

    The magnetospheric boundary layer and the plasma-sheet boundary layer are the primary boundary layers of the earth's outer magnetosphere. Recent satellite observations indicate that they provide for more than 50 percent of the plasma and energy transport in the outer magnetosphere although they constitute less than 5 percent by volume. Relative to the energy density in the source regions, plasma in the magnetospheric boundary layer is predominantly deenergized whereas plasma in the plasma-sheet boundary layer has been accelerated. The reconnection hypothesis continues to provide a useful framework for comparing data sampled in the highly dynamic magnetospheric environment. Observations of 'flux transfer events' and other detailed features near the boundaries have been recently interpreted in terms of nonsteady-state reconnection. Alternative hypotheses are also being investigated. More work needs to be done, both in theory and observation, to determine whether reconnection actually occurs in the magnetosphere and, if so, whether it is important for overall magnetospheric dynamics.

  11. Wave observations in outer planet magnetospheres

    NASA Technical Reports Server (NTRS)

    Scarf, F. L.

    1985-01-01

    The first measurements of plasma waves and wave-particle interactions in the magnetospheres of the outer planets were provided by instruments on Voyager 1 and 2. At Jupiter, the observations yielded new information on upstream electrons and ions, bow shock dissipation processes, trapped radio waves in the magnetospheres and extended Jovian magnetotail, pitch angle diffusion mechanisms and whistlers from atmospheric lightning. Many of these same emissions were detected at Saturn. In addition, the Voyager plasma wave instruments detected dust particles associated with the tenuous outer rings of Saturn as they impacted the spacecraft. Most of the plasma wave activity at Jupiter and Saturn is in the audio range, and recordings of the wave observations have been useful for analysis.

  12. Irradiation chemistry in the outer solar system

    NASA Astrophysics Data System (ADS)

    Brown, Michael E.

    2014-11-01

    The dark, reddish tinged surfaces of icy bodies in the outer solar are usually attributed to the long term irradiation of simple hydrocarbons such as methane leading to the loss of hydrogen and the production of long carbon chains. While methane is stable and detected on the most massive bodies in the Kuiper belt, evidence of active irradiation chemistry is scant except for the presence of ethane on methane-rich Makemake and possible detections of ethane on more methane-poor Pluto and Quaoar. We have obtained deep high signal-to-noise spectra of Makemake from 1.5 to 2.5 microns in an attempt to trace the radiation chemistry in the outer solar system beyond the initial ethane formation. We present the first astrophysical detections of solid ethylene, acetylene, and possibly propane -- all expected products of the continued irradiation of methane, and use these species to map the chemical pathway from methane to long-chain hydrocarbons.

  13. Outer magnetospheric fluctuations and pulsar timing noise

    NASA Technical Reports Server (NTRS)

    Cheng, K. S.

    1987-01-01

    The Cheng, Ho, and Ruderman (1986) outer-magnetosphere gap model was used to investigate the stability of Crab-type outer magnetosphere gaps for pulsars having the parameter (Omega-square B) similar to that of the Crab pulsar. The Lamb, Pines, and Shaham (1978) fluctuating magnetosphere noise model was applied to the Crab pulsar to examine the type of the equation of state that best describes the structure of the neutron star. The noise model was also applied to other pulsars, and the theoretical results were compared with observational data. The results of the comparison are consistent with the stiff equation of state, as suggested by the vortex creep model of the neutron star interior. The timing-noise observations also contribute to the evidence for the existence of superfluid in the core of the neutron star.

  14. EDITORIAL: Integrated assessments of environmental change on the Tibetan Plateau Integrated assessments of environmental change on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Sheng, Yongwei; Yao, Tandong

    2009-12-01

    The Tibetan Plateau is one of the Earth's most sensitive regions in responding to climate change due to its extremely high altitude and the presence of permafrost and glaciers. The cryosphere, biosphere and hydrosphere of the plateau have been undergoing significant changes. Due to the low human population density, environmental changes on the plateau are largely driven by natural processes. Thus, the plateau provides a unique and comprehensive site for global change studies. This focus issue on Climate Change on the Tibetan Plateau aims to address both paleo and recent environmental changes across the plateau to facilitate our understanding of this remote and under-studied area. We invited a wide spectrum of contributions to address climate change, permafrost degradation, glacier/snow/ice dynamics, lake dynamics, land- cover/land-use changes, and their interactions on the plateau. Collectively, the diverse contributions in this special issue are expected to present the recent advancement of the above topics and beyond. See the PDF for the full text of the editorial. Focus on Climate Change on the Tibetan Plateau Contents Does a weekend effect in diurnal temperature range exist in the eastern and central Tibetan Plateau? Qinglong You, Shichang Kang, Wolfgang-Albert Flügel, Arturo Sanchez-Lorenzo, Yuping Yan, Yanwei Xu and Jie Huang Diurnal variations of summertime precipitation over the Tibetan Plateau in relation to orographically-induced regional circulations Xiaodong Liu, Aijuan Bai and Changhai Liu Lake-level fluctuations since the Last Glaciation in Selin Co (lake), Central Tibet, investigated using optically stimulated luminescence dating of beach ridges Dewen Li, Yingkui Li, Baoqi Ma, Guocheng Dong, Liqiang Wang and Junxiang Zhao Recent changes in Imja Glacial Lake and its damming moraine in the Nepal Himalaya revealed by in situ surveys and multi-temporal ASTER imagery Koji Fujita, Akiko Sakai, Takayuki Nuimura, Satoru Yamaguchi and Rishi R Sharma Changes

  15. Planetary magnetism in the outer solar system.

    NASA Technical Reports Server (NTRS)

    Sonett, C. P.

    1973-01-01

    A brief review of the salient considerations which apply to the existence of magnetic fields in connection with planetary and subplanetary objects in the outer solar system is given. Consideration is given to internal dynamo fields, fields which might originate from interaction with the solar wind or magnetospheres (externally driven dynamos) and lastly fossil magnetic fields such as have been discovered on the moon. Where possible, connection is made between magnetism, means of detection, and internal body properties.

  16. Fluxgate magnetometers for outer planets exploration

    NASA Technical Reports Server (NTRS)

    Acuna, M. H.

    1974-01-01

    The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

  17. Cosmic ray gradients in the outer heliosphere

    NASA Technical Reports Server (NTRS)

    Fillius, W.; Wake, B.; Ip, W.-H.; Axford, I.

    1983-01-01

    Launched in 1972 and 1973 respectively, the Pioneer 10 and 11 spacecraft are now probing the outer heliosphere on their final escape from the sun. The data in this paper extend for almost an entire solar cycle from launch to early 1983, when Pioneer 10 was at a heliocentric distance of 29 AU and Pioneer 11, 13 AU. The UCSD instruments on board were used to study the gradient, and to look at the time and spatial variations of the cosmic ray intensities.

  18. Photopolarimetry team outer planets mission definition phase

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The work is reported of the Photopolarimetry Team in identifying scientific objectives for photometer/polarimeter experiments for outer planet flyby missions. A discussion of the scientific objectives which can be attained with a photometer/polarimeter experiment, and summaries of the special studies which were performed for the Photopolarimetry Team are presented along with a description of the photometer/polarimeter design which was developed for the Meteoroid Detection Team.

  19. A model environment for outer zone electrons

    NASA Technical Reports Server (NTRS)

    Singley, G. W.; Vette, J. I.

    1972-01-01

    A brief morphology of outer zone electrons is given to illustrate the nature of the phenomena that we are attempting to model. This is followed by a discussion of the data processing that was done with the various data received from the experimenters before incorporating it into the data base from which this model was ultimately derived. The details of the derivation are given, and several comparisons of the final model with the various experimental measurements are presented.

  20. Differential Rotation within the Earth's Outer Core

    NASA Technical Reports Server (NTRS)

    Hide, R.; Boggs, D. H.; Dickey, J. O.

    1998-01-01

    Non-steady differential rotation drive by bouyancy forces within the Earth's liquid outer core (OC) plays a key role not only in the generation of the main geomagnetic field by the magnetohydrodynamic (MHD) dynamo process but also in the excitation of irregular fluctuations in the angular speed of rotation of the overlying solid mantle, as evidenced by changes in the length of the day (LOD) on decadal and longer timescales (1-8).

  1. THE YOUNG OUTER DISK OF M83

    SciTech Connect

    Davidge, T. J.

    2010-08-01

    Deep near-infrared images recorded with NICI on Gemini South are used to investigate the evolved stellar content in the outer southeast quadrant of the spiral galaxy M83. A diffuse population of asymptotic giant branch (AGB) stars is detected, indicating that there are stars outside of the previously identified young and intermediate age star clusters in the outer disk. The brightest AGB stars have M {sub K} {>=} -8, and the AGB luminosity function (LF) is well matched by model LFs that assume ages {<=}1 Gyr. The specific star formation rate (SFR) during the past few Gyr estimated from AGB star counts is consistent with that computed from mid-infrared observations of star clusters at similar radii, and it is concluded that the disruption timescale for star clusters in the outer disk is <<1 Gyr. The LF and specific frequency of AGB stars vary with galactocentric radius, in a manner that is indicative of lower luminosity-weighted ages at larger radii. Modest numbers of red supergiants are also found, indicating that there has been star formation during the past 100 Myr, while the ratio of C stars to M giants is consistent with that expected for a solar metallicity system that has experienced a constant SFR for the past few Gyr. The results drawn from the properties of resolved AGB stars are broadly consistent with those deduced from integrated light observations in the UV.

  2. Causes and consequences of outer core stratification

    NASA Astrophysics Data System (ADS)

    Helffrich, George; Kaneshima, Satoshi

    2013-10-01

    The Earth’s outer core appears to be compositionally layered. Exotic mechanisms such as an original chemically layered core preserved from the Earth’s accretionary period, or compositionally different core material delivered by a Moon-creating impactor are conceivable, but require a core whose outermost part has been stratified throughout core history, relying on unknowable processes to achieve. Barodiffusion and core-mantle reaction lead to layers significantly thinner than observed. We show that a balance of mass transferred from the inner core to the top of the outer core is possible, and that the stratification could arise as a byproduct of light element accumulation. However, if a subadiabatic thermal gradient at the top of the outer core exists that quells radial flow, it could serve as a witness of light element accumulation by preventing mixing with the convecting part of the core. The temperature difference through a subadiabatic layer could be 80-300 K and carry heat fluxes through the core-mantle boundary of 0.5-23 TW, given uncertainty in core properties.

  3. CLOSURE WELD DEVELOPMENT FOR 3013 OUTER CONTAINERS

    SciTech Connect

    Daugherty, W.; Howard, S.; Peterson, K.; Stokes, M.

    2009-11-10

    Excess plutonium materials in the DOE complex are packaged and stored in accordance with DOE-STD-3013. This standard specifies requirements for the stabilization of such materials and subsequent packaging in dual nested seal-welded containers. Austenitic stainless steels have been selected for container fabrication. The inner 3013 container provides contamination control while the outer 3013 container is the primary containment vessel and is the focus of this paper. Each packaging site chose a process for seal welding the outer 3013 containers in accordance with its needs and expertise. The two processes chosen for weld closure were laser beam welding (LBW) and gas tungsten arc welding (GTAW). Following development efforts, each system was qualified in accordance with DOE-STD-3013 prior to production use. The 3013 outer container closure weld joint was designed to accommodate the characteristics of a laser weld. This aspect of the joint design necessitated some innovative process and equipment considerations in the application of the GTAW process. Details of the weld requirements and the development processes are presented and several potential enhancements for the GTAW system are described.

  4. Outer membrane proteins of pathogenic spirochetes

    PubMed Central

    Cullen, Paul A.; Haake, David A.; Adler, Ben

    2009-01-01

    Pathogenic spirochetes are the causative agents of several important diseases including syphilis, Lyme disease, leptospirosis, swine dysentery, periodontal disease and some forms of relapsing fever. Spirochetal bacteria possess two membranes and the proteins present in the outer membrane are at the site of interaction with host tissue and the immune system. This review describes the current knowledge in the field of spirochetal outer membrane protein (OMP) biology. What is known concerning biogenesis and structure of OMPs, with particular regard to the atypical signal peptide cleavage sites observed amongst the spirochetes, is discussed. We examine the functions that have been determined for several spirochetal OMPs including those that have been demonstrated to function as adhesins, porins or to have roles in complement resistance. A detailed description of the role of spirochetal OMPs in immunity, including those that stimulate protective immunity or that are involved in antigenic variation, is given. A final section is included which covers experimental considerations in spirochetal outer membrane biology. This section covers contentious issues concerning cellular localization of putative OMPs, including determination of surface exposure. A more detailed knowledge of spirochetal OMP biology will hopefully lead to the design of new vaccines and a better understanding of spirochetal pathogenesis. PMID:15449605

  5. Radio wave scattering in the outer heliosphere

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.

    1995-01-01

    Current models for the 2-3 kHz emissions observed by the Voyager spacecraft in the outer heliosphere involve 2f(p) radiation generated near the termination shock or the heliopause. Radio wave scattering by solar wind density irregularities strongly affects observed sources of f(p) and 2f(p) emission in the inner heliosphere and the characteristics of astrophysical sources. In particular, the angular size, brightness temperature, and time variability of the source are strongly affected by scattering, thereby having major implications for the inferred size, energy budget, time variability, location, and nature of the source if scattering is ignored. This paper addresses whether scattering is important for interpreting the Voyager 2-3 kHz emissions. Quantitative calculations (with and without diffraction) are performed for the angular broadening of an outer heliospheric source as a function of path length, radiation frequency relative to f(p) and the spectrum of density irregularities. The effects of scattering in both the solar wind and the heliosheath are considered. Predictions for radial gradients in the source's apparent angular size and in the source's modulation index are presented. The calculations are compared with observations and the results discussed. First estimates suggest that scattering plausibly dominates the observed source size. The observed trend in modulation index with heliocentric distance is consistent with scattering being important and the source being in the outer heliosphere. Additional arguments for scattering being important are summarized.

  6. Drainage Evolution during the Uplift of the Central Anatolia Plateau

    NASA Astrophysics Data System (ADS)

    Brocard, G. Y.; Meijers, M. J.; Willenbring, J. K.; Kaymakci, N.; Whitney, D. L.

    2015-12-01

    The Central Anatolian plateau formed in the past 8-6 Myrs, associated to a change in tectonic regime, from contraction to extensional escape tectonics. We have examined the response of the river drainage of Central Anatolia to the rise of the plateau uplift and to the formation of the Anatolian microplate, tracking changes in drainage organization. Anatolia experienced widespread rock uplift and erosion in the Late Oligocene, generating a narrow, steep, and quickly eroding mountain range above the future southern plateau margin. A regionally widespread marine transgression resulted from wholesale foundering of this orogen in Early Miocene time. Widespread planation surfaces overlapped by Miocene marine carbonates bevel this topography, indicating that relief had been reduced to a low elevation pedimented landscape by the end of the Middle Miocene. Plateau uplift initiated around 11 My ago in Eastern Anatolia; it was echoed in Central Anatolia by a short-lived phase of contraction and localized uplifts that predate escape tectonics and mark the beginning of the current topographic differentiation of the southern plateau margin. The through-going drainage network inherited disintegrated, and a vast zone of inward drainage formed at the location of the future plateau interior. Between 8 and 6 My, the southern plateau margin (i.e. the Tauride Mountains) emerged. δ18O analyses on lacustrine and pedogenic carbonates show that the southern plateau margin, if not the plateau interior, had experienced enough uplift by 5 My to generate a substantial rain shadow over the plateau interior. Being disconnected from the regional base level from the start, the plateau interior was able to rise without experiencing substantial dissection. It reconnected to all surrounding sediment sinks (Mediterranean Sea, Black Sea and Persian Gulf) over the past 5 My. We discuss the mechanisms that have driven this reconnection. Bottom-up processes of integration such as drainage divide retreat

  7. Central Plateau Cleanup at DOE's Hanford Site - 12504

    SciTech Connect

    Dowell, Jonathan

    2012-07-01

    The discussion of Hanford's Central Plateau includes significant work in and around the center of the Hanford Site - located about 7 miles from the Columbia River. The Central Plateau is the area to which operations will be shrunk in 2015 when River Corridor cleanup is complete. This work includes retrieval and disposal of buried waste from miles of trenches; the cleanup and closure of massive processing canyons; the clean-out and demolition to 'slab on grade' of the high-hazard Plutonium Finishing Plant; installation of key groundwater treatment facilities to contain and shrink plumes of contaminated groundwater; demolition of all other unneeded facilities; and the completion of decisions about remaining Central Plateau waste sites. A stated goal of EM has been to shrink the footprint of active cleanup to less than 10 square miles by 2020. By the end of FY2011, Hanford will have reduced the active footprint of cleanup by 64 percent exceeding the goal of 49 percent. By 2015, Hanford will reduce the active footprint of cleanup by more than 90 percent. The remaining footprint reduction will occur between 2015 and 2020. The Central Plateau is a 75-square-mile region near the center of the Hanford Site including the area designated in the Hanford Comprehensive Land Use Plan Environmental Impact Statement (DOE 1999) and Record of Decision (64 FR 61615) as the Industrial-Exclusive Area, a rectangular area of about 20 square miles in the center of the Central Plateau. The Industrial-Exclusive Area contains the 200 East and 200 West Areas that have been used primarily for Hanford's nuclear fuel processing and waste management and disposal activities. The Central Plateau also encompasses the 200 Area CERCLA National Priorities List site. The Central Plateau has a large physical inventory of chemical processing and support facilities, tank systems, liquid and solid waste disposal and storage facilities, utility systems, administrative facilities, and groundwater monitoring

  8. THE LONG-LIVED UV ''PLATEAU'' OF SN 2012aw

    SciTech Connect

    Bayless, Amanda J.; Roming, Peter W. A.; Pritchard, Tyler A.; Kuin, Paul; Brown, Peter J.; Botticella, Maria Teresa; Dall'Ora, Massimo; Frey, Lucille H.; Even, Wesley; Fryer, Chris L.; Maund, Justyn R.; Fraser, Morgan

    2013-02-10

    Observations with the Swift UV Optical Telescope have unambiguously uncovered for the first time a long-lived, UV ''plateau'' in a Type II-P supernova (SN). Although this flattening in slope is hinted at in a few other SNe, due to its proximity and minimal line-of-sight extinction, SN 2012aw has afforded the first opportunity to clearly observe this UV plateau. The observations of SN 2012aw revealed all Swift UV and u-band light curves initially declined rapidly, but 27 days after the explosion the light curves flattened. Some possible sources of the UV plateau are the same thermal process that causes the optical plateau, heating from radioactive decay, or a combination of both processes.

  9. Incision into the eastern Andean Plateau during Pliocene cooling.

    PubMed

    Lease, Richard O; Ehlers, Todd A

    2013-08-16

    Canyon incision into mountain topography is commonly used as a proxy for surface uplift driven by tectonic or geodynamic processes, but climatic changes can also instigate incision. The ~1250-kilometer (km)-long eastern margin of the Andean Plateau hosts a series of 1.5- to 2.5-km-deep canyons that cross major deformation zones. Using (U-Th)/He thermochronology, we document a transition from Miocene faulting to Pliocene canyon incision across the northeastern plateau margin. Regionally, widespread Pliocene incision into the eastern plateau margin is concurrent with a shift in global climate from early Pliocene warmth to late Pliocene cooling. Enhanced moisture transport onto the Andean Plateau driven by sea surface temperature changes during cooling is the likely pacemaker for canyon incision. PMID:23950534

  10. Orogenic plateau growth in the Zagros of Iran

    NASA Astrophysics Data System (ADS)

    Allen, Mark; Blanc, Eric; Saville, Christopher

    2010-05-01

    This paper concerns how Turkish-Iranian plateau grows by incorporating the Zagros fold and thrust belt. The plateau's tectonic boundary can be defined as the limit of significant seismogenic thrusting, which occurs close to the regional 1 km elevation contour. The geomorphic boundary is less distinct, but occurs northeast of the limit of active thrusting, because of a time lag during which mountainous relief converts to the subdued plateau geomorphology. Most of the High Zagros and ~25,000 km2 of the Zagros Simple Folded Zone behave as part of the plateau. The Dezful Embayment is a low strain zone in the western Zagros Simple Folded Zone, implying locally strong basement. Deformation is correspondingly more intense northeast of the Embayment, where the highest elevations and steepest slopes in the Zagros occur. As a consequence of the Embayment, lateral plateau growth is more limited in the western Zagros than the east (Fars). A more uniform structure across the Fars region has produced a lower orogenic taper, and a wider region of the Zagros behaves as part of the Turkish-Iranian plateau. Climatic variation along the Zagros is likely to act as a positive feedback on this tectonic variation, although the rates are not well-constrained. Relatively high orographic precipitation northeast of the Dezful Embayment promotes exhumation. The more arid climate in the Fars region should subdue exhumation, implying quicker crustal thickening and elevation for any given shortening. This enhances lateral plateau growth. Regional plateau elevations >1 km may relate to underlying warm and partially molten mantle.

  11. Crust and Mantle Structure Beneath the Colorado Plateau (Invited)

    NASA Astrophysics Data System (ADS)

    Grand, S. P.; van Wijk, J. W.; Baldridge, W. S.; Aster, R. C.; Ni, J. F.; Wilson, D.

    2010-12-01

    The La Ristra experiment consisted of a northwest trending linear deployment of 72 broadband seismic stations from West Texas to western Utah with 15 to 20 km spacing. The resulting 1400 km seismic line provides unprecedented images of crust and mantle along a cross section that crosses the Colorado Plateau from near Mount Taylor in the east to the Marysvale volcanic field in the west. Surface wave analysis shows the Colorado Plateau to have a 120-150 km thick high seismic velocity lid that we identify with cold lithosphere. A sharp negative gradient below 120-150 km depth indicates a sharp boundary to the lithosphere at depth with hot asthenosphere in contact with the base of the lithosphere. Receiver function analysis shows central Plateau crust to be 42-50 km thick thinning to 30-35 km thick at the edges. Isostatic calculations show that only a fraction of the Plateau elevation can be explained by thickened crust thus the high topography of the Plateau has a largely mantle source. Bodywave tomography is consistent with the surface wave analysis but shows that at both edges of the Plateau there are narrow (50-100km) high velocity zones extending to at least 200 km depth. We interpret these seismic anomalies as mantle downwellings that are part of small edge convection cells initiated by lateral temperature gradients created by extension in the Great Basin and Rio Grande Rift. Numerical modeling indicates the convection is significantly eroding the lithosphere at the edges of the Plateau accounting for the high elevations observed there. Associated upwellings are responsible for the late Neogene-Quaternary magmatism surrounding the Plateau.

  12. Continental crust beneath the Agulhas Plateau, Southwest Indian Ocean

    SciTech Connect

    Tucholke, B.E.; Houtz, R.E.; Barrett, D.M.

    1981-05-10

    The Agulhas Plateau lies 500 km off the Cape of Good Hope in the southwestern Indian Ocean. Acoustic basement beneath the northern one third of this large, aseismic structural high has rugged morphology, but basement in the south is anomalously smooth, excepting a 30- to 90-km-wide zone with irregular relief that trends south-southwest through the center of the plateau. Seismic refraction profiles across the southern plateau indicate that the zone of irregular acoustic basement overlies thickened oceanic crust and that continental crust, locally thinned and intruded by basalts, underlies several regions of smooth acoustic basement. Recovery of quartzo-feldspathic gneisses in dredge hauls confirms the presence of continental crust. The smoothness of acoustic basement probably results from erosion (perhaps initially subaerial) of topographic highs with depositions and cementation of debris in ponds to form high-velocity beds. Basalt flows and sills also may contribute locally to form smooth basement. The rugged basement of the northern plateau appears to be of oceanic origin. A plate reconstruction to the time of initial opening of the South Atlantic places the continental part of the southern plateau adjacent to the southern edge of the Falkland Plateau, and both abut the western Mozambique Ridge. Both the Agulhas and Falkland plateaus were displaced westward during initial rifting in the Early Cretaceous. Formation of an RRR triple junction at the northern edge of the Agulhas continental fragment during middle Cretaceous time may explain the origin of the rugged, thickened oceanic crust beneath plateau as well as the apparent extension of the continental crust and intrusion of basaltic magmas beneath the southern plateau.

  13. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  14. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  15. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  16. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  17. 49 CFR 195.9 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Outer continental shelf pipelines. 195.9 Section... HAZARDOUS LIQUIDS BY PIPELINE General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify on all their respective pipelines the specific...

  18. 49 CFR 192.10 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Outer continental shelf pipelines. 192.10 Section... shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf (as defined in the Outer Continental Shelf Lands Act; 43 U.S.C. 1331) must identify on all their respective pipelines...

  19. 75 FR 1076 - Outer Continental Shelf Civil Penalties

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-08

    ... Minerals Management Service Outer Continental Shelf Civil Penalties AGENCY: Minerals Management Service.... SUMMARY: The Outer Continental Shelf Lands Act requires the MMS to review the maximum daily civil penalty assessment for violations of regulations governing oil and gas operations in the Outer Continental Shelf...

  20. 49 CFR 195.9 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Outer continental shelf pipelines. 195.9 Section... HAZARDOUS LIQUIDS BY PIPELINE General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify on all their respective pipelines the specific...

  1. 49 CFR 192.10 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Outer continental shelf pipelines. 192.10 Section... shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf (as defined in the Outer Continental Shelf Lands Act; 43 U.S.C. 1331) must identify on all their respective pipelines...

  2. 49 CFR 192.10 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Outer continental shelf pipelines. 192.10 Section... shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf (as defined in the Outer Continental Shelf Lands Act; 43 U.S.C. 1331) must identify on all their respective pipelines...

  3. 49 CFR 195.9 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Outer continental shelf pipelines. 195.9 Section... HAZARDOUS LIQUIDS BY PIPELINE General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify on all their respective pipelines the specific...

  4. 49 CFR 192.10 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Outer continental shelf pipelines. 192.10 Section... shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf (as defined in the Outer Continental Shelf Lands Act; 43 U.S.C. 1331) must identify on all their respective pipelines...

  5. 49 CFR 195.9 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Outer continental shelf pipelines. 195.9 Section... HAZARDOUS LIQUIDS BY PIPELINE General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify on all their respective pipelines the specific...

  6. 49 CFR 195.9 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Outer continental shelf pipelines. 195.9 Section... HAZARDOUS LIQUIDS BY PIPELINE General § 195.9 Outer continental shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf must identify on all their respective pipelines the specific...

  7. 49 CFR 192.10 - Outer continental shelf pipelines.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Outer continental shelf pipelines. 192.10 Section... shelf pipelines. Operators of transportation pipelines on the Outer Continental Shelf (as defined in the Outer Continental Shelf Lands Act; 43 U.S.C. 1331) must identify on all their respective pipelines...

  8. 33 CFR 117.323 - Outer Clam Bay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Outer Clam Bay. 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay. The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  9. 33 CFR 117.323 - Outer Clam Bay

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Outer Clam Bay 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  10. 33 CFR 117.323 - Outer Clam Bay.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Outer Clam Bay. 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay. The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  11. 33 CFR 117.323 - Outer Clam Bay

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Outer Clam Bay 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  12. 33 CFR 117.323 - Outer Clam Bay

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Outer Clam Bay 117.323 Section... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Florida § 117.323 Outer Clam Bay The drawspan of the Outer Clam Bay Boardwalk Drawbridge shall open on signal if at least 30 minutes advance notice is given....

  13. Blowing Snow Over the Antarctic Plateau

    NASA Technical Reports Server (NTRS)

    Mahesh, Ashwin; Eager, Rebecca; Campbell, James R.; Spinhirne, James D.

    2002-01-01

    Studies of blowing snow over Antarctica have been limited greatly by the remoteness and harsh conditions of the region. Space-based observations are also of lesser value than elsewhere, given the similarities between ice clouds and snow-covered surfaces, both at infrared and visible wavelengths. It is only in recent years that routine ground-based observation programs have acquired sufficient data to overcome the gap in our understanding of surface blowing snow. In this paper, observations of blowing snow from visual observers' records as well as ground-based spectral and lidar programs at South Pole station are analyzed to obtain the first climatology of blowing snow over the Antarctic plateau. Occurrence frequencies, correlation with wind direction and speed, typical layer heights, as well as optical depths are determined. Blowing snow is seen in roughly one third of the visual observations and occurs under a narrow range of wind directions. The near-surface layers typically a few hundred meters thick emit radiances similar to those from thin clouds. Because blowing snow remains close to the surface and is frequently present, it will produce small biases in space-borne altimetry; these must be properly estimated and corrected.

  14. Dendroclimatic reconstructions for the southern Colorado plateau

    SciTech Connect

    Dean, J.S.; Funkhouser, G.S.

    1995-09-01

    A geographical network of climate sensitive tree-ring chronologies consisting of 25 archaeological sequences and two bristlecone pine series provides the basis for high resolution reconstructions of low and high frequency climatic variability on the southern Colorado Plateau over the last 1,500 years. Qualitative and quantitative dendroclimatic analyses of these data produce annual retrodictions of yearly and seasonal precipitation and summer Palmer Drought Severity Indices for each station and reconstructions of regional scale patterns in climatic variability. These reconstructions provide detailed information on climatic fluctuations that affected biotic and human populations as well as long-term baseline data for evaluating present-day climate and estimating future climatic trends. When integrated with other measures of past environmental variability, these reconstructions specify periods of favorable and unfavorable environmental conditions that would have affected past human populations of the region. The severest degradation, which occurred between A.D. 1250 and 1450, probably was causally related to numerous cultural changes that occurred at the end of the l3th century including the Anasazi abandonment of the Four Comers area. Projecting environmental patterns that characterized the last two millennia into the future indicates potential hazards to long term uranium mill waste disposal and containment and the potential and limitations of environmental restoration.

  15. Composition of Syrtis Major volcanic plateau

    NASA Technical Reports Server (NTRS)

    Mustard, John F.; Erard, S.; Bibring, Jean-Pierre; Langevin, Yves; Head, James W.; Pieters, Carle M.

    1991-01-01

    Syrtis Major, a low-relief volcanic shield centered near 295 degrees 10 degrees N, is an old, well-preserved and exposed volcanic region on Mars which formed at the end of the heavy bombardment period. The composition of these volcanic materials has importance for understanding the thermal and chemical history of Mars. Imaging spectrometer data of the Syrtis Major volcanic plateau are used in this analysis to identify major compositional components. First and second order even channel reflectance spectra between 0.77 and 2.55 microns from four broad classes of materials on Syrtis Major are given. For the volcanic materials, there are three primary classes characterized by albedo, slope, and shape of the 10 micron band. To emphasize the latter, straight line continua were removed from each spectral segment and replotted in another figure. Each spectrum shows a band minima near 0.96 microns and 2.15 microns indicative of pyroxene mineral absorptions. Comparison of these band minima with studies of pyroxene reflectance spectra suggests that the pyroxenes in the volcanics of Syrtis Major are high calcium pyroxene with a Ca/(Mg+Fe+Ca) ratio of 0.2 to 0.3. The most likely pyroxene is an augite.

  16. Gas hydrates of outer continental margins

    SciTech Connect

    Kvenvolden, K.A. )

    1990-05-01

    Gas hydrates are crystalline substances in which a rigid framework of water molecules traps molecules of gas, mainly methane. Gas-hydrate deposits are common in continental margin sediment in all major oceans at water depths greater than about 300 m. Thirty-three localities with evidence for gas-hydrate occurrence have been described worldwide. The presence of these gas hydrates has been inferred mainly from anomalous lacoustic reflectors seen on marine seismic records. Naturally occurring marine gas hydrates have been sampled and analyzed at about tensites in several regions including continental slope and rise sediment of the eastern Pacific Ocean and the Gulf of Mexico. Except for some Gulf of Mexico gas hydrate occurrences, the analyzed gas hydrates are composed almost exclusively of microbial methane. Evidence for the microbial origin of methane in gas hydrates includes (1) the inverse relation between methane occurence and sulfate concentration in the sediment, (2) the subparallel depth trends in carbon isotopic compositions of methane and bicarbonate in the interstitial water, and (3) the general range of {sup 13}C depletion ({delta}{sub PDB}{sup 13}C = {minus}90 to {minus}60 {per thousand}) in the methane. Analyses of gas hydrates from the Peruvian outer continental margin in particular illustrate this evidence for microbially generated methane. The total amount of methane in gas hydrates of continental margins is not known, but estimates of about 10{sup 16} m{sup 3} seem reasonable. Although this amount of methane is large, it is not yet clear whether methane hydrates of outer continental margins will ever be a significant energy resource; however, these gas hydrates will probably constitute a drilling hazard when outer continental margins are explored in the future.

  17. The Young Outer Disk of M83

    NASA Astrophysics Data System (ADS)

    Davidge, T. J.

    2010-08-01

    Deep near-infrared images recorded with NICI on Gemini South are used to investigate the evolved stellar content in the outer southeast quadrant of the spiral galaxy M83. A diffuse population of asymptotic giant branch (AGB) stars is detected, indicating that there are stars outside of the previously identified young and intermediate age star clusters in the outer disk. The brightest AGB stars have M K >= -8, and the AGB luminosity function (LF) is well matched by model LFs that assume ages <=1 Gyr. The specific star formation rate (SFR) during the past few Gyr estimated from AGB star counts is consistent with that computed from mid-infrared observations of star clusters at similar radii, and it is concluded that the disruption timescale for star clusters in the outer disk is Lt1 Gyr. The LF and specific frequency of AGB stars vary with galactocentric radius, in a manner that is indicative of lower luminosity-weighted ages at larger radii. Modest numbers of red supergiants are also found, indicating that there has been star formation during the past 100 Myr, while the ratio of C stars to M giants is consistent with that expected for a solar metallicity system that has experienced a constant SFR for the past few Gyr. The results drawn from the properties of resolved AGB stars are broadly consistent with those deduced from integrated light observations in the UV. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a co-operative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council of Canada (Canada), CONICYT (Chile), the Australian Research Council (Australia), the Ministerio da Ciencia e Technologia (Brazil), and the Ministerio de Ciencia, Tecnologia e Innovacion Productiva (Argentina).

  18. Surface ices in the outer solar system

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.; Cruikshank, Dale P.

    1994-01-01

    Planetary volatile inventories are products of several factors: (1) condensation-accretion of pre-planetary material which determines the bulk volatile inventory; (2) energy history of a planet, including timing, causes, and mechanisms of degassing; (3) the volatile sinks, including temporary, long term, and permanent; and (4) external processes operating on the volatile inventory. Information regarding the current surface compositions provide insight into both internal and surface-atmosphere evolutionary history. Our discussion focuses upon the surface composition of outer solar system planets and satellites as determined by spacecraft and telescopic spectral observations. We provide a review and an update of the recent work by Cruikshank and Brown that includes more recent observations and interpretations. In the context of formation and evolution of solar system bodies, the interesting ices typically considered are simple molecules formed from elements having high cosmic abundances. These mainly include ices of H2O, NH3, SO2, H2S, CH4, CO, CO2, and N2. In the solid state, these ices have vibrational spectral features, analogous to their gaseous counterparts but rotational transitions are quenched, that lie in the near- and mid-infrared. The overtone and combination modes, occurring in the visible and near-IR region, are of particular importance as standard observational techniques used to identify these ices rely upon reflected solar energy. Table I summarizes the ices found on various bodies in the outer solar system. H2O is most abundant surface material in the inner and middle regions while more volatile species appear to dominate surfaces in the outermost edge of the outer solar system.

  19. Methane Group Ions in Saturn's Outer Magnetosphere

    NASA Astrophysics Data System (ADS)

    Sittler, Edward C.; Hartle, R. E.; Cooper, J. F.; Johnson, R. E.; Smith, H. T.; Shappirio, M. D.; Simpson, D. J.

    2008-09-01

    In Hartle et al. [2006a,b] they reported evidence of keV methane group ions within Saturn's outer magnetosphere during Cassini's TA Titan flyby. They presented evidence of CH4+ pickup ions within the mass loading region of the magnetospheric interaction with Titan. They also reported that keV water group ions W+ (i.e., O+) were present and dominated the magnetospheric heavy ion composition. These water group ions probably result from the emission of fast neutrals from the Enceladus torus via charge exchange reactions but still gravitationally bound to Saturn [see Johnson et al., 2005 and Sittler et al. 2006] and then become ionized in the outer magnetosphere where the pickup energies are keV. Since O+ and CH4+ have similar mass the primary discriminator is the O- fragment which appears at a different time-of-flight (TOF) than that for mass 16. One way to separate the methane from the O+ is to measure the relative abundance of the mass 16 peak with the O- peak. If there is a methane torus as a consequence of the hydrodynamic model of Strobel [2008], then one expects the presence of CH3+ ions and not CH4+ ions, since the methane dissociates to CH3 before they get ionized. Here we will be reporting on a further search for evidence of methane group ions within Saturn's outer magnetosphere. References: Hartle, R. E., et al., Geophys. Res. Lett., 33, L08201, 2006a Hartle, R. E., et al., Planet. Space Sci., 54, 1211, 2006b Johnson. R.E., et. Astrophys. J. Letts, 644, L137-L139, 2005 Sittler, E. C., Jr., et al., JGR, 111, A09223, 2006 Strobel, D. F., Icarus, 193, 588, [2008

  20. Does the climate warming hiatus exist over the Tibetan Plateau?

    PubMed Central

    Duan, Anmin; Xiao, Zhixiang

    2015-01-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998–2013 (0.25 °C decade−1), compared with that during 1980–1997 (0.21 °C decade−1). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud–radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud–radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau. PMID:26329678

  1. Does the climate warming hiatus exist over the Tibetan Plateau?

    PubMed

    Duan, Anmin; Xiao, Zhixiang

    2015-01-01

    The surface air temperature change over the Tibetan Plateau is determined based on historical observations from 1980 to 2013. In contrast to the cooling trend in the rest of China, and the global warming hiatus post-1990s, an accelerated warming trend has appeared over the Tibetan Plateau during 1998-2013 (0.25 °C decade(-1)), compared with that during 1980-1997 (0.21 °C decade(-1)). Further results indicate that, to some degree, such an accelerated warming trend might be attributable to cloud-radiation feedback. The increased nocturnal cloud over the northern Tibetan Plateau would warm the nighttime temperature via enhanced atmospheric back-radiation, while the decreased daytime cloud over the southern Tibetan Plateau would induce the daytime sunshine duration to increase, resulting in surface air temperature warming. Meanwhile, the in situ surface wind speed has recovered gradually since 1998, and thus the energy concentration cannot explain the accelerated warming trend over the Tibetan Plateau after the 1990s. It is suggested that cloud-radiation feedback may play an important role in modulating the recent accelerated warming trend over the Tibetan Plateau. PMID:26329678

  2. Investigations of the gravity profile below the Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Shen, W. B.; Han, J. C.

    2012-04-01

    Scientists pay great attention to the structure and dynamics of the Tibetan plateau due to the fact that it is a natural experiment site for geoscience studies. The gravity profiles below the Tibetan plateau with successive high-accuracy play more and more significant role in studying the structure and evolution of the Tibetan plateau. This study focuses on determining the inner gravity field of the Tibetan plateau until to the depth of D and interpret possible mechanism of the gravity profile below the Tibetan plateau, especially reinvestigating the isostasy problem (Pratt hypothesis and Airy hypothesis). The inner gravity field below the Tibetan plateau is determined based on a simple technique (i.e. a combination of Newtonian integral, downward continuation of gravity field, and "remove-restore" scheme) and the following datasets: the external Earth gravitational model EGM2008 and the digital topographic model DTM2006.0 released by NGA (National Geospatial-Intelligence Agency, USA), and the crust density distribution model CRUST2.0 released by NGS (National Geological Survey, USA). This study is supported by Natural Science Foundation China (grant No.40974015; No.41174011).

  3. Eccentric features in Saturn's outer C ring

    NASA Technical Reports Server (NTRS)

    Porco, Carolyn C.; Nicholson, Philip D.

    1987-01-01

    The present search for possible eccentric and inclined features in the outer C ring of Saturn measured all sharp-edged feature radii in Voyager C ring data. The Maxwell ringlet and two other narrow ringlets, 1.470R(s) and 1.495R(s) are found to be eccentric; the latter is best fitted by a model describing a freely precessing Keplerian ellipse, while the former is not conclusively fitted by either a resonant forcing or a free precession model. These two eccentric ringlets are compared with the Titan and Maxwell ringlets.

  4. Eccentric features in Saturn's outer C ring

    SciTech Connect

    Porco, C.C.; Nicholson, P.D.

    1987-11-01

    The present search for possible eccentric and inclined features in the outer C ring of Saturn measured all sharp-edged feature radii in Voyager C ring data. The Maxwell ringlet and two other narrow ringlets, 1.470R(s) and 1.495R(s) are found to be eccentric; the latter is best fitted by a model describing a freely precessing Keplerian ellipse, while the former is not conclusively fitted by either a resonant forcing or a free precession model. These two eccentric ringlets are compared with the Titan and Maxwell ringlets. 51 references.

  5. Outer planet spacecraft temperature testing and analysis

    NASA Technical Reports Server (NTRS)

    Hoffman, A. R.; Avila, A.

    2002-01-01

    Unmanned spacecraft flown on missions to the outer planets of the solar system have included flybys, planetary orbiters, and atmospheric probes during the last three decades. The thermal design, test, and analysis approach applied to these spacecraft evolved from the passive thermal designs applied to the earlier lunar and interplanetary spacecraft. The inflight temperature data from representative sets of engineering subsystems and science instruments from a subset of these spacecraft are compared to those obtained during the ground test programs and from the prelaunch predictions. Several lessons are presented with specific recommendations for considerations for new projects to aid in the planning of cost effective temperature design, test, and analysis programs.

  6. Dishwasher For Earth Or Outer Space

    NASA Technical Reports Server (NTRS)

    Tromble, Jon D.

    1991-01-01

    Dishwashing machine cleans eating utensils in either Earth gravity or zero gravity of outer space. Cycle consists of three phases: filling, washing, and draining. Rotation of tub creates artificial gravity aiding recirculation of water during washing phase in absence of true gravity. Centrifugal air/water separator helps system function in zero gravity. Self-cleaning filter contains interdigitating blades catching solid debris when water flows between them. Later, blades moved back and forth in scissor-like manner to dislodge debris, removed by backflow of water.

  7. Dark matter in the outer solar system

    NASA Technical Reports Server (NTRS)

    Owen, T.; Cruikshank, D.; De Bergh, C.; Geballe, T.

    1994-01-01

    There are now a large number of small bodies in the outer solar system that are known to be covered with dark material. Attempts to identify that material have been thwarted by the absence of discrete absorption features in the reflection spectra of these planetesimals. An absorption at 2.2 micrometers that appeared to be present in several objects has not been confirmed by new observations. Three absorptions in the spectrum of the unusually red planetesimal 5145 Pholus are well-established, but their identity remains a mystery.

  8. Atmospheric entry probes for outer planet exploration. Outer planet entry probe technical summary

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The use of unmanned space probes for investigating the conditions existing on and around the outer planets of the solar system is discussed. The subjects included in the report are: (1) the design of a common entry probe for outer planet missions, (2) the significant trades related to the development of a common probe design, (3) the impact of bus selection on probe design, (4) the impact of probe requirements on bus modifications, and (5) the key technology elements recommended for advanced development. Drawings and illustrations of typical probes are included to show the components and systems used in the space probes.

  9. Changes in Spatial Patterns of Caragana stenophylla along a Climatic Drought Gradient on the Inner Mongolian Plateau

    PubMed Central

    Xie, Li-Na; Guo, Hong-Yu; Gabler, Christopher A.; Li, Qing-Fang; Ma, Cheng-Cang

    2015-01-01

    Few studies have investigated the influence of water availability on plant population spatial patterns. We studied changes in the spatial patterns of Caragana stenophylla along a climatic drought gradient within the Inner Mongolian Plateau, China. We examined spatial patterns, seed density, “nurse effects” of shrubs on seedlings, transpiration rates and water use efficiency (WUE) of C. stenophylla across semi-arid, arid, and intensively arid zones. Our results showed that patches of C. stenophylla populations shifted from a random to a clumped spatial pattern towards drier environments. Seed density and seedling survival rate of C. stenophylla decreased from the semi-arid zone to the intensively arid zone. Across the three zones, there were more C. stenophylla seeds and seedlings underneath shrub canopies than outside shrub canopies; and in the intensively arid zone, there were almost no seeds or seedlings outside shrub canopies. Transpiration rates of outer-canopy leaves and WUE of both outer-canopy and inner-canopy leaves increased from the semi-arid zone to the intensively arid zone. In the intensively arid zone, transpiration rates and WUE of inner-canopy leaves were significantly lower and higher, respectively, than those of outer-canopy leaves. We conclude that, as drought stress increased, seed density decreased, seed proportions inside shrubs increased, and “nurse effects” of shrubs on seedlings became more important. These factors, combined with water-saving characteristics associated with clumped spatial patterns, are likely driving the changes in C. stenophylla spatial patterns. PMID:25785848

  10. Changes in spatial patterns of Caragana stenophylla along a climatic drought gradient on the Inner Mongolian Plateau.

    PubMed

    Xie, Li-Na; Guo, Hong-Yu; Gabler, Christopher A; Li, Qing-Fang; Ma, Cheng-Cang

    2015-01-01

    Few studies have investigated the influence of water availability on plant population spatial patterns. We studied changes in the spatial patterns of Caragana stenophylla along a climatic drought gradient within the Inner Mongolian Plateau, China. We examined spatial patterns, seed density, "nurse effects" of shrubs on seedlings, transpiration rates and water use efficiency (WUE) of C. stenophylla across semi-arid, arid, and intensively arid zones. Our results showed that patches of C. stenophylla populations shifted from a random to a clumped spatial pattern towards drier environments. Seed density and seedling survival rate of C. stenophylla decreased from the semi-arid zone to the intensively arid zone. Across the three zones, there were more C. stenophylla seeds and seedlings underneath shrub canopies than outside shrub canopies; and in the intensively arid zone, there were almost no seeds or seedlings outside shrub canopies. Transpiration rates of outer-canopy leaves and WUE of both outer-canopy and inner-canopy leaves increased from the semi-arid zone to the intensively arid zone. In the intensively arid zone, transpiration rates and WUE of inner-canopy leaves were significantly lower and higher, respectively, than those of outer-canopy leaves. We conclude that, as drought stress increased, seed density decreased, seed proportions inside shrubs increased, and "nurse effects" of shrubs on seedlings became more important. These factors, combined with water-saving characteristics associated with clumped spatial patterns, are likely driving the changes in C. stenophylla spatial patterns. PMID:25785848

  11. Stellar evolution in the outer Galaxy

    NASA Astrophysics Data System (ADS)

    Szczerba, Ryszard; Siódmiak, Natasza; Leśniewska, Aleksandra; Karska, Agata; Sewiło, Marta

    2016-07-01

    We investigate the distribution of different classes of spectroscopically identified sources and theoretical models in the color-color diagrams (CCDs) combining the near-infrared (NIR) and mid-infrared (MIR) data to develop a method to classify Outer Galaxy sources detected with the Spitzer Space Telescope (hereafter Spitzer) SMOG survey in the IRAC 3.68.0 µm and MIPS 24 µm bands. We supplement the Spitzer data with the data from other satellite and ground-based surveys. The main goal of our study is to discover and characterize the population of intermediate- and low-mass young stellar objects (YSOs) in the Outer Galaxy and use it to study star formation in a significantly different environment than the Galaxy inside the solar circle. Since the YSOs can be confused with evolved stars in the MIR, these classes of objects need to be carefully separated. Here we present the initial results of our analysis using the Ks-[8.0] vs. Ks-[24] CCD as an example. The evolved stars separated from YSOs in the YSO selection process will be investigated in detail in the follow-up study.

  12. Radio Emissions from the Outer Heliosphere

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Kurth, W. S.

    1996-01-01

    For nearly fifteen years the Voyager 1 and 2 spacecraft have been detecting an unusual radio emission in the outer heliosphere in the frequency range from about 2 to 3 kHz. Two major events have been observed, the first in 1983-84 and the second in 1992-93. In both cases the onset of the radio emission occurred about 400 days after a period of intense solar activity, the first in mid-July 1982, and the second in May-June 1991. These two periods of solar activity produced the two deepest cosmic ray Forbush decreases ever observed. Forbush decreases are indicative of a system of strong shocks and associated disturbances propagating outward through the heliosphere. The radio emission is believed to have been produced when this system of shocks and disturbances interacted with one of the outer boundaries of the heliosphere, most likely in the vicinity of the the heliopause. The emission is believed to be generated by the shock-driven Langmuir-wave mode conversion mechanism, which produces radiation at the plasma frequency (f(sub p)) and at twice the plasma frequency (2f(sub p)). From the 400-day travel time and the known speed of the shocks, the distance to the interaction region can be computed, and is estimated to be in the range from about 110 to 160 AU.

  13. Residual Stress Testing of Outer 3013 Containers

    SciTech Connect

    Dunn, K.

    2004-02-12

    A Gas Tungsten Arc Welded (GTAW) outer 3013 container and a laser welded outer 3013 container have been tested for residual stresses according to the American Society for Testing Materials (ASTM) Standard G-36-94 [1]. This ASTM standard describes a procedure for conducting stress-corrosion cracking tests in boiling magnesium chloride (MgCl2) solution. Container sections in both the as-fabricated condition as well as the closure welded condition were evaluated. Significantly large residual stresses were observed in the bottom half of the as-fabricated container, a result of the base to can fabrication weld because through wall cracks were observed perpendicular to the weld. This observation indicates that regardless of the closure weld technique, sufficient residual stresses exist in the as-fabricated container to provide the stress necessary for stress corrosion cracking of the container, at the base fabrication weld. Additionally, sufficiently high residual stresses were observed in both the lid and the body of the GTAW as well as the laser closure welded containers. The stresses are oriented perpendicular to the closure weld in both the container lid and the container body. Although the boiling MgCl2 test is not a quantitative test, a comparison of the test results from the closure welds shows that there are noticeably more through wall cracks in the laser closure welded container than in the GTAW closure welded container.

  14. Fabrication of Spherical Reflectors in Outer Space

    NASA Technical Reports Server (NTRS)

    Wang, Yu; Dooley, Jennifer; Dragovan, Mark; Serivens, Wally

    2005-01-01

    A process is proposed for fabrication of lightweight spherical reflectors in outer space for telescopes, radio antennas, and light collectors that would be operated there. The process would obviate the relatively massive substrates and frames needed to support such reflectors in normal Earth gravitation. According to the proposal, fabrication of a reflector would begin with blowing of a bubble to the specified reflector radius. Taking advantage of the outer-space vacuum as a suitable environment for evaporative deposition of metal, a metal-evaporation source would be turned on and moved around the bubble to deposit a reflective metal film over the specified reflector area to a thickness of several microns. Then the source would be moved and aimed to deposit more metal around the edge of the reflector area, increasing the thickness there to approximately equal to 100 micron to form a frame. Then the bubble would be deflated and peeled off the metal, leaving a thin-film spherical mirror having an integral frame. The mirror would then be mounted for use. The feasibility of this technology has been proved by fabricating a prototype at JPL. As shown in the figure, a 2-in. (.5-cm) diameter hemispherical prototype reflector was made from a polymer bubble coated with silver, forming a very smooth surface.

  15. The Utility of Outer Planet Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hill, Steven M.

    2015-05-01

    Amateur astronomers can now routinely record disk integrated spectra of the outer planets at moderate to high spectral and temporal resolution. Initial studies of the application of small telescope spectroscopy to the outer planets (including Titan) were published in the early 2000's. This paper seeks to revisit these capabilities in conjunction with advances in understanding the target atmospheres, available low-cost instrumentation, and current observational needs within the research community. First, observations and data reduction are presented. Second, the basic capability of small-scope planetary spectroscopy is re-validated and spectra of Jupiter, Saturn, Titan, Uranus and Neptune are compared to professional spectra at similar resolutions. Third, effective line-of-sight methane number density, etaN(CH4), is retrieved using best fits to integrated band strengths for both classical single reflecting layer models and classical homogeneous scattering models. The observations and methane number densities obtained lie within the scatter seen in published literature. Fourth, the challenges to making highly repeatable, well calibrated observations are examined. This is done in the context of monitoring for transient changes in band strengths, e.g., as result of longitudinal variations clouds, hazes and/or surface albedo. Jupiter provides an easy, high signal-to-noise test case where the detectability of Great Red Spot transits is evaluated. In conclusion, we summarize the results, make recommendations for extending this work and suggest a campaign that could be carried out immediately by appropriately equipped amateurs.

  16. SDC conceptual design: Scintillating fiber outer tracker

    SciTech Connect

    Adams, D.; Baumbaugh, A.; Bird, F.; SDC Collaboration

    1992-01-22

    The authors propose an all-scintillating fiber detector for the purpose of outer tracking for the SDC. The objectives of this tracking system are to: (1) provide a first level trigger for {vert_bar}{eta}{vert_bar} < 2.3 with sharp p{sub T} threshold with the ability to resolve individual beam crossings; (2) provide pattern recognition capability and momentum resolution which complements and extends the capabilities of the inner silicon tracking system; (3) provide three dimensional linkage with outer detection systems including the shower maximum detector, muon detectors, and calorimetry; (4) provide robust tracking and track-triggering at the highest luminosities expected at the SSC. The many attractive features of a fiber tracker include good position resolution, low occupancy, low mass in the active volume, and excellent resistance to radiation damage. An additional important feature, especially at the SSC, is the intrinsically prompt response time of a scintillating fiber. This property is exploited in the construction of a level 1 trigger sensitive to individual beam crossings.

  17. Outer membrane proteins of Methylococcus capsulatus (Bath).

    PubMed

    Fjellbirkeland, A; Kleivdal, H; Joergensen, C; Thestrup, H; Jensen, H B

    1997-08-01

    Membranes obtained from whole-cell lysates of Methylococcus capsulatus (Bath) were separated by Triton X-100 extraction. The resulting insoluble fraction was enriched in outer membranes as assessed by electron microscopy and by the content of beta-hydroxy palmitic acid and particulate methane monooxygenase. Major proteins with molecular masses of approximately 27, 40, 46, 59, and 66 kDa were detected by SDS-PAGE of the Triton-X-100-insoluble membranes. MopA, MopB, MopC, MopD, and MopE (Methylococcus outer membrane protein) are proposed to designate these proteins. Several of the Mop proteins exhibited heat-modifiable properties in SDS-PAGE and were influenced by the presence of 2-mercaptoethanol in the sample buffer. The 46- and 59-kDa bands migrated as a single high-molecular-mass 95-kDa oligomer under mild denaturing conditions. When reconstituted into black lipid membranes, this oligomer was shown to serve as a channel with an estimated single-channel conductance of 1.4 nS in 1 M KCl. PMID:9238104

  18. Heat flow in the north-central Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Bodell, John Michael; Chapman, David S.

    1982-04-01

    We report new heat flow measurements at 25 evenly distributed sites in the north-central Colorado Plateau. Heat flow values computed for these new sites and one previously published site range from 43 to 116 mW m-2 but fall into the following distinct subsets related to physiographic and tectonic elements within the Plateau: (1) heat flow of 51 mW m-2 (12 sites; s.d. 6) in the San Rafael Swell and Green River Desert which constitute the core of the Colorado Plateau at this latitude, (2) heat flows of 69 mW m-2 (5 sites; s.d. 10) and 88 mW m-2 (4 sites; s.d. 19) in successive parallel north-south bands approaching the Wasatch Plateau to the west but still 80 km east of the Basin and Range physiographic boundary, (3) heat flow of 64 mW m-2 (5 sites; s.d. 2) along the Salt Anticline trend which strikes northwest in the region of Moab, Utah. Heat flow results for the entire Colorado Plateau have been reexamined in view of our new results, and the overall pattern supports the concept of a low heat flow `thermal interior' for the plateau surrounded by a periphery some 100 km wide having substantially higher heat flow. Average heat flow in the thermal interior is about 60 mW m-2 compared to 80-90 mW m-2 in the periphery. This regional heat flow pattern supports a model of Tertiary lithospheric thinning under the Colorado Plateau whereby the plateau is still in transient thermal response and a 15-20 m.y. lag between uplift and corresponding surface heat flow anomaly is to be expected. The position of the heat flow transition between our interior and peripheral regions in the northwest plateau is roughly consistent with lateral warming and weakening of the Colorado Plateau lithosphere initiated at the Basin and Range boundary some 20 m.y. ago.

  19. Eocene Tibetan Plateau remnants preserved in the Northwest Himalaya

    NASA Astrophysics Data System (ADS)

    van der Beek, P. A.; van Melle, J.; Guillot, S.; Pêcher, A.; Reiners, P. W.; Nicolescu, S.; Latif, M.

    2009-04-01

    The northwest Himalaya shows strongly contrasting relief, opposing deeply incised mountain ranges characterized by extremely rapid exhumation and some of the highest peaks in the world (i.e., the Karakorum range and Nanga Parbat massif) to high-elevation, low-relief areas such as the 4000-m high Deosai plateau in northern Pakistan and the 5000-m high Tso Morari in Indian Ladakh. The origin and evolution of such plateau regions in the syntaxis of the most active continental collision in the world remain elusive. Here, we report the first low-temperature thermochronology (apatite fission-track, apatite and zircon (U-Th)/He) data from the Deosai plateau and use thermal history modelling to show that it has undergone continuous slow (≤ 200 m/Myr) denudation and has thus remained tectonically stable for the last 35 Myr at least. The inferred history of constant slow denudation of the plateau contradicts the hypothesis that widespread low-relief surfaces in the northwest Himalaya result from efficient, km-scale glacial erosion during Quaternary times; such erosion would have been recorded as a phase of rapid recent denudation that is not observed in the data. Slow continuous denudation since Eocene times, i.e. only 15-20 Myr after the onset of India-Asia collision implies that the Deosai plateau surface developed early in the Himalayan history and limits the phase of orogenic relief growth in the Ladakh-Kohistan arc to the early Paleogene. Although thermochronology data do not directly record surface uplift, the simplest explanation for the inferred constant denudation rates is that the plateau had reached its present-day elevation already during the Eocene, as a later phase of surface uplift would have triggered an erosional response that would have been recorded by the thermochronology data. We use morphological analyses to characterise such plateaux and identify them at the scale of the entire northwest Himalaya and compare our thermochronological data with

  20. Paleomagnetic Data From Ontong Java Plateau are Anomalous ˜ Did the Plateau Form on Another Plate?

    NASA Astrophysics Data System (ADS)

    Sager, W. W.

    2004-12-01

    A recent study of Ocean Drilling Program basalt core paleomagnetic data from Ontong Java Plateau (OJP) found paleolatitudes that disagree with previous estimates of the Early Cretaceous Pacific APWP, a result attributed to poor quality of data used in prior pole calculations [Riisager, P., S. Hall, M. Antretter, X. Zhao, Earth Planet. Sci. Lett., 208, p. 235, 2003]. My compilation of paleomagnetic data from Cretaceous Pacific basalt cores drilled by the Deep Sea Drilling Project and Ocean Drilling Program shows that paleocolatitude data in of ages 118-129 Ma display greater scatter than other age bins. The only factor that allows this data group to be coherently subdivided is whether or not the coring site is located on OJP. Without OJP data, paleocolatitude scatter is much less and gives a similar pole position (48.9° N, 327.1° E, N=40) to data in the 110-118 Ma interval. Data from the plateau give a pole that is 15° farther north (64.9° N, 323.4° E; N=37), indistinguishable from late Jurassic and earliest Cretaceous skewness poles. The OJP and non-OJP poles are distinct at the 95% confidence level despite having indistinguishable mean ages of 121.6 ±1.1 Ma (OJP) and 123.4 ±4.1 (non-OJP). Because Ontong Java Plateau data come from 6 different sites spread over the northern plateau, tectonic tilting is not a likely explanation for the difference. Also unlikely are systematic errors such as incomplete averaging of secular variation (large number of independent magnetic units sampled), inaccurate radiometric dates (many high quality dates), or inadequate paleomagnetic techniques (detailed studies by several different investigators). Rapid true polar wander does not seem a plausible explanation because global true polar wander curves have a different trend. Perhaps the simplest explanation is the one often used when anomalous data are found within a plate: the anomalous region had a different history of tectonic drift. In this scenario, OJP formed on a separate

  1. Aftershock Decay Rates in the Iranian Plateau

    NASA Astrophysics Data System (ADS)

    Ommi, S.; Zafarani, H.; Zare, M.

    2016-07-01

    Motivated by the desire to have more information following the occurrence of damaging events, the main purpose of this article is to study aftershock sequence parameters in the Iranian plateau. To this end, the catalogue of the Iranian earthquakes between 2002 to the end of 2013 has been collected and homogenized among which 15 earthquakes have been selected to study their aftershock decay rates. For different tectonic provinces, the completeness magnitudes ( M c) of the earthquake catalogue have been calculated in different time intervals. Also, the M c variability in spatial and temporal windows has been determined for each selected event. For major Iranian earthquakes, catalogue of aftershocks has been collected thanks to three declustering methods: first, the classical windowing method of Gardner and Knopoff (Bull Seismol Soc Am 64:1363-1367, 1974); second, a modified version of this using spatial windowing based on the Wells and Coppersmith (Bull Seismol Soc Am 84:974-1002, 1994) relations; and third, the Burkhard and Grünthal (Swiss J Geosci 102:149-188, 2009) scheme. Effects of the temporal windows also have been investigated using the time periods of 1 month, 100 days, and 1 year in the declustering method of Gardner and Knopoff (Bull Seismol Soc Am 64:1363-1367, 1974). In the next step, the modified Omori law coefficients have been calculated for the 15 selected earthquakes. The calibrated regional generic model describing the temporal and magnitude distribution of aftershocks is of interest for time-dependent seismic hazard forecasts. The regional characteristics of the aftershock decay rates have been studied for the selected Iranian earthquakes in the Alborz, Zagros and Central Iran regions considering their different seismotectonics regimes. However, due to the lack of sufficient data, no results have been reported for the Kopeh-Dagh and Makran seismotectonic regions.

  2. Aftershock Decay Rates in the Iranian Plateau

    NASA Astrophysics Data System (ADS)

    Ommi, S.; Zafarani, H.; Zare, M.

    2016-04-01

    Motivated by the desire to have more information following the occurrence of damaging events, the main purpose of this article is to study aftershock sequence parameters in the Iranian plateau. To this end, the catalogue of the Iranian earthquakes between 2002 to the end of 2013 has been collected and homogenized among which 15 earthquakes have been selected to study their aftershock decay rates. For different tectonic provinces, the completeness magnitudes (M c) of the earthquake catalogue have been calculated in different time intervals. Also, the M c variability in spatial and temporal windows has been determined for each selected event. For major Iranian earthquakes, catalogue of aftershocks has been collected thanks to three declustering methods: first, the classical windowing method of uc(Gardner) and uc(Knopoff) (Bull Seismol Soc Am 64:1363-1367, 1974); second, a modified version of this using spatial windowing based on the uc(Wells) and uc(Coppersmith) (Bull Seismol Soc Am 84:974-1002, 1994) relations; and third, the uc(Burkhard) and uc(Grünthal) (Swiss J Geosci 102:149-188, 2009) scheme. Effects of the temporal windows also have been investigated using the time periods of 1 month, 100 days, and 1 year in the declustering method of uc(Gardner) and uc(Knopoff) (Bull Seismol Soc Am 64:1363-1367, 1974). In the next step, the modified Omori law coefficients have been calculated for the 15 selected earthquakes. The calibrated regional generic model describing the temporal and magnitude distribution of aftershocks is of interest for time-dependent seismic hazard forecasts. The regional characteristics of the aftershock decay rates have been studied for the selected Iranian earthquakes in the Alborz, Zagros and Central Iran regions considering their different seismotectonics regimes. However, due to the lack of sufficient data, no results have been reported for the Kopeh-Dagh and Makran seismotectonic regions.

  3. Isolation of the outer membrane and characterization of the major outer membrane protein from Spirochaeta aurantia.

    PubMed Central

    Kropinski, A M; Parr, T R; Angus, B L; Hancock, R E; Ghiorse, W C; Greenberg, E P

    1987-01-01

    The outer membrane of Spirochaeta aurantia was isolated after cells were extracted with sodium lauryl sarcosinate and was subsequently purified by differential centrifugation and KBr isopycnic gradient centrifugation. The purified outer membrane was obtained in the form of carotenoid-containing vesicles. Four protein species with apparent molecular weights of 26,000 (26K), 36.5K, 41K, and 48.5K were readily observed as components of the vesicles. The 36.5K protein was the major polypeptide and constituted approximately 90% of the outer membrane protein observed on sodium dodecyl sulfate-polyacrylamide gels. Under mild denaturing conditions the 36.5K major protein exhibited an apparent molecular weight of approximately 90,000. This, together with the results of protein cross-linking studies, indicates that the 36.5K polypeptide has an oligomeric conformation in the native state. Reconstitution of solubilized S. aurantia outer membrane into lipid bilayer membranes revealed the presence of a porin, presumably the 36.5K protein, with an estimated channel diameter of 2.3 nm based on the measured single channel conductance of 7.7 nS in 1 M KCl. Images PMID:3025168

  4. Variations in Upper Mantle Seismic Structure Across the Ethiopian Plateau

    NASA Astrophysics Data System (ADS)

    Weeraratne, D. S.; Solomon, S. C.; Nyblade, A. A.

    2006-05-01

    The Ethiopian plateau, disrupted by the Main Ethiopian Rift (MER) and adjacent to the nearby Red Sea spreading center, resides within a complex tectonic environment. We use Rayleigh wave phase velocity data from the Ethiopian Broadband Seismic Experiment to study the upper mantle seismic structure of the plateau. Dispersion curves indicate phase velocities that are significantly lower than other continental lithosphere by as much as 8% for periods between 18 and 91 s. Lateral velocity variations show a narrow low-velocity anomaly elongated in the NE-SW direction located within the rift boundaries. Phase velocities within the western and eastern plateau are ~6% higher than within the MER. Shear wave velocity inversions indicate a high-velocity lid that extends to 100 km ± 20 km depth and marks the base of the lithosphere. Azimuthal anisotropy within the western plateau is resolvable for periods up to 60 s; a 1.6% peak-to-peak amplitude gradually rotates in azimuth from NNE at short periods to NE at 60 s. This azimuthal rotation is consistent with lateral variations in the fast direction of SKS splitting studies between the rift and western plateau. The change in Rayleigh wave anisotropy at long periods indicates that the NE splitting direction observed within the western plateau may be due to a component of deep sublithospheric flow. We suggest that a transition in anisotropic fabric is controlled by the combined effects of aligned melt pockets within the MER and pre-existing Mozambique sutures at shallow lithospheric depths and asthenospheric flow parallel to plate spreading at greater depths. Our results may also be consistent with sublithospheric flow of mantle plume material that rises beneath the Ethiopian plateau and flows northeastward to the Red Sea spreading center.

  5. Linking the Galapagos hotspot and the Caribbean Plateau

    NASA Astrophysics Data System (ADS)

    Nerlich, Rainer; Clark, Stuart R.; Bunge, Hans-Peter

    2014-05-01

    Wide agreement exists that the Caribbean plate has a Pacific origin and that parts of it depict an igneous Plateau of up to 20 km thick crust. However, the origin of this thickened crust remains debated. One of the first suggestions for its origin was the arrival of a plume, whose remnant might be the Galapagos hotspot. More recently, it has been argued that reconstruction models predicted the Galapagos hotspot a thousand or more kilometres away from the Caribbean plate at the time of Plateau formation (~88 ?? 94 Ma). These authors primarily relied on the Caribbean Plateau moving into its present position relative to the Americas only in the last few million years. Secondarily, the authors assumed that the hotspot was fixed in an Indian-Atlantic hotspot reference frame. Here, we explore the idea that the Plateau moved into position around the time of the initiation of convergence between the North and South America, about 54.5 Ma. In addition, we adopt a fixed Pacific hotspot reference frame and compare our results to the recently developed Global Moving Hotspot Reference Frame. We show that both frames lead to good correlations between the paleo-positions of the Caribbean Plate and the Galapagos hotspot. As this result is consistent with abundant geochemical evidence that lends support for both a plume origin as well as the similarity between the Galapagos hotspot and rocks from the Plateau itself, we argue that alternative mechanisms to explain the thickened crust of the Caribbean Plateau are unnecessary. Additionally, based on our new plate reconstruction model, we present an age distribution of the lithosphere underneath the thickened crust of the Caribbean Plateau that has remained speculative until now.

  6. High Tibetan Plateau: a Nature Reserve of C3 Flora

    NASA Astrophysics Data System (ADS)

    Zhuang, G.; Pagani, M.; Brandon, M. T.

    2015-12-01

    Uplift of the Tibetan Plateau and associated climate changes leading to enhanced seasonality in precipitation and drying, are argued to have induced a global ecological shift from C3-frorest to C4-grassland between 8 and 5 million years ago. However, both tectonic and climatic changes predate the timing of the C3-C4 transition, with paleoaltimetry studies pointing to a high Tibetan Plateau no later than 10 Ma and the existence of an intense monsoon since ca. 11 Ma. To better understand the role of the Tibetan Plateau, we present results of a paleoecology study based on the carbon isotope compositions of leaf-wax n-alkanes (δ13Calk) from Qaidam basin, an intermontane basin on the youngest and the northernmost portion of Tibetan Plateau. Samples were collected from a 5-km thick, fluvial-lacustrine sequence dated 15 Ma to 1.8 Ma. Organic geochemical indices and detrital thermochronological studies preclude post-depositional thermal alteration of the studied materials. Our results, which show persistently low δ13Calk values, are consistent with the dominance of C3 flora on the Tibetan Plateau, in contrast to the prominent C4 rise surrounding the Tibetan Plateau and around the globe. We argue that a high Tibetan Plateau, established prior to the global ecological C3-C4 shift, served as a shelter of C3 flora since the Miocene. High-elevation and cold environments provided a competitive advantage for C3 by damping/counteracting the physiological advantage of C4 which outperforms C3 plants under warm, high-irradiance, water-stress and low pCO2 conditions.

  7. The Colorado Plateau II: biophysical, socioeconomic, and cultural research

    USGS Publications Warehouse

    Mattson, David J.

    2005-01-01

    The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through grazing and the wildland-urban interface issues, to parameters of climate change on the Plateau. The book also introduces economic perspectives by considering shifting patterns and regional disparities in the Colorado Plateau economy. A series of chapters on mountain lions explores the human-wildland interface. These chapters deal with the entire spectrum of challenges associated with managing this large mammal species in Arizona and on the Colorado Plateau, conveying a wealth of timely information of interest to wildlife managers and enthusiasts. Another provocative set of chapters on biophysical resources explores the management of forest restoration, from the micro scale all the way up to large-scale GIS analyses of ponderosa pine ecosystems on the Colorado Plateau. Given recent concerns for forest health in the wake of fires, severe drought, and bark-beetle infestation, these chapters will prove enlightening for forest service, park service, and land management professionals at both the federal and state level, as well as general readers interested in how forest management practices will ultimately affect their recreation activities. With broad coverage that touches on topics as diverse as movement patterns of rattlesnakes, calculating watersheds, and rescuing looted rockshelters, this volume stands as a compendium of cutting-edge research on the Colorado Plateau that offers a wealth of insights for many scholars.

  8. Outer Planet Assessment Group (OPAG) Recommended Exploration Strategy for the Outer Planets 2013-2022

    NASA Astrophysics Data System (ADS)

    McKinnon, William B.; Steering Committee, Opag; Planets Community, Outer

    2010-05-01

    The Outer Solar System provides critical clues to how solar systems form and evolve, how planetary systems become habitable, and how life has evolved in our solar system. NASA's Outer Planets Assessment Group (OPAG) was established to identify scientific priorities and pathways for Outer Solar System exploration. Fundamental new discoveries are best made with a mixture of mission sizes that includes large (flagship) missions, and medium-sized and smaller-sized (as practical) missions, along with vigorous support for basic research, data analysis, and technology development — a balanced strategy most efficiently implemented as an Outer Planets Exploration Program. Missions to the Outer Solar System are major undertakings, requiring large and expensive launch vehicles, long mission durations, highly reliable (frequently radiation hard) and autonomous spacecraft, and radioisotope power sources in most cases. OPAG has recommended to the US National Research Council Planetary Science Decadal Survey to explore the possibilities for ‘small flagship' class missions to be considered, providing a greater range of choice and capabilities in the mix to balance program size and science return. With the Galileo mission concluded, the Cassini equinox mission in progress, and Juno in development, OPAG has strongly endorsed the competitive selection by NASA of the Jupiter Europa Orbiter (JEO) as the next Outer Planets Flagship and as part of the Europa Jupiter System Mission (EJSM) with ESA, a collaboration that includes a Ganymede orbiter and an increased focus on Jupiter science; OPAG has strongly recommended support of JEO and EJSM in the Decadal Survey. In addition, OPAG has strongly endorsed approval by NASA of the Cassini Solstice Mission, including the Juno-like end-of-mission scenario, given the likely phenomenal return on investment. OPAG also advocates the need for a focused technology program for the next Outer Planet Flagship Mission after EJSM, in order to be ready

  9. Radio seismology of the outer solar corona

    NASA Astrophysics Data System (ADS)

    Zaqarashvili, Teimuraz; Melnik, Valentin; Brazhenko, Anatoliy; Panchenko, Mykhaylo; Konovalenko, Alexander; Dorovskyy, Vladimir; Rucker, Helmut

    2014-05-01

    Observed oscillations of coronal loops in extreme ultraviolet (EUV) lines have been successfully used to estimate plasma parameters in the inner corona (< 0.2R0, where R0 is the solar radius). However, coronal seismology in EUV lines fails for higher altitudes because of rapid decrease in line intensity. We aim to use radio observations to estimate the plasma parameters of the outer solar corona (> 0.2R0). We used the large Ukrainian radio telescope URAN-2 to observe type IV radio bursts at the frequency range of 8-32 MHz during the time interval of 09:50-12:30 UT on April 14, 2011. The burst was connected to C2.3 flare, which occurred in AR 11190 during 09:38-09:49 UT. The dynamic spectrum of radio emission shows clear quasi-periodic variations in the emission intensity at almost all frequencies. Wavelet analysis at four different frequencies (29 MHz, 25 MHz, 22 MHz, and 14 MHz) shows the quasi-periodic variation of emission intensity with periods of ~ 34 min and ~ 23 min. The periodic variations can be explained by the first and second harmonics of vertical kink oscillation of transequatorial coronal loops, which were excited by the same flare. The apex of transequatorial loops may reach up to 1.2 R0 altitude. We derive and solve the dispersion relation of trapped magnetohydrodynamic (MHD) oscillations in a longitudinally inhomogeneous magnetic slab. The analysis shows that a thin (with width to length ratio of 0.1), dense (with the ratio of internal and external densities of ≥ 20) magnetic slab with weak longitudinal inhomogeneity may trap the observed oscillations. Seismologically estimated Alfvén speed inside the loop at the height of ~ 1 R0 is ~ 1000 km s-1. The magnetic field strength at this height is estimated as ~ 0.9 G. Extrapolation of magnetic field strength to the inner corona gives ~ 10 G at the height of 0.1 R0. Radio observations can be successfully used for the sounding of the outer solar corona, where EUV observations of coronal loops fail

  10. Prokaryotic Community Structure Driven by Salinity and Ionic Concentrations in Plateau Lakes of the Tibetan Plateau

    PubMed Central

    Zhong, Zhi-Ping; Liu, Ying; Miao, Li-Li; Wang, Fang; Chu, Li-Min; Wang, Jia-Li

    2016-01-01

    The prokaryotic community composition and diversity and the distribution patterns at various taxonomic levels across gradients of salinity and physiochemical properties in the surface waters of seven plateau lakes in the Qaidam Basin, Tibetan Plateau, were evaluated using Illumina MiSeq sequencing. These lakes included Lakes Keluke (salinity, <1 g/liter), Qing (salinity, 5.5 to 6.6 g/liter), Tuosu (salinity, 24 to 35 g/liter), Dasugan (salinity, 30 to 33 g/liter), Gahai (salinity, 92 to 96 g/liter), Xiaochaidan (salinity, 94 to 99 g/liter), and Gasikule (salinity, 317 to 344 g/liter). The communities were dominated by Bacteria in lakes with salinities of <100 g/liter and by Archaea in Lake Gasikule. The clades At12OctB3 and Salinibacter, previously reported only in hypersaline environments, were found in a hyposaline lake (salinity, 5.5 to 6.6 g/liter) at an abundance of ∼1.0%, indicating their ecological plasticity. Salinity and the concentrations of the chemical ions whose concentrations covary with salinity (Mg2+, K+, Cl−, Na+, SO42−, and Ca2+) were found to be the primary environmental factors that directly or indirectly determined the composition and diversity at the level of individual clades as well as entire prokaryotic communities. The distribution patterns of two phyla, five classes, five orders, five families, and three genera were well predicted by salinity. The variation of the prokaryotic community structure also significantly correlated with the dissolved oxygen concentration, pH, the total nitrogen concentration, and the PO43− concentration. Such correlations varied depending on the taxonomic level, demonstrating the importance of comprehensive correlation analyses at various taxonomic levels in evaluating the effects of environmental variable factors on prokaryotic community structures. Our findings clarify the distribution patterns of the prokaryotic community composition in plateau lakes at the levels of individual clades as well as whole

  11. Prokaryotic Community Structure Driven by Salinity and Ionic Concentrations in Plateau Lakes of the Tibetan Plateau.

    PubMed

    Zhong, Zhi-Ping; Liu, Ying; Miao, Li-Li; Wang, Fang; Chu, Li-Min; Wang, Jia-Li; Liu, Zhi-Pei

    2016-03-01

    The prokaryotic community composition and diversity and the distribution patterns at various taxonomic levels across gradients of salinity and physiochemical properties in the surface waters of seven plateau lakes in the Qaidam Basin, Tibetan Plateau, were evaluated using Illumina MiSeq sequencing. These lakes included Lakes Keluke (salinity, <1 g/liter), Qing (salinity, 5.5 to 6.6 g/liter), Tuosu (salinity, 24 to 35 g/liter), Dasugan (salinity, 30 to 33 g/liter), Gahai (salinity, 92 to 96 g/liter), Xiaochaidan (salinity, 94 to 99 g/liter), and Gasikule (salinity, 317 to 344 g/liter). The communities were dominated by Bacteria in lakes with salinities of <100 g/liter and by Archaea in Lake Gasikule. The clades At12OctB3 and Salinibacter, previously reported only in hypersaline environments, were found in a hyposaline lake (salinity, 5.5 to 6.6 g/liter) at an abundance of ∼1.0%, indicating their ecological plasticity. Salinity and the concentrations of the chemical ions whose concentrations covary with salinity (Mg(2+), K(+), Cl(-), Na(+), SO4 (2-), and Ca(2+)) were found to be the primary environmental factors that directly or indirectly determined the composition and diversity at the level of individual clades as well as entire prokaryotic communities. The distribution patterns of two phyla, five classes, five orders, five families, and three genera were well predicted by salinity. The variation of the prokaryotic community structure also significantly correlated with the dissolved oxygen concentration, pH, the total nitrogen concentration, and the PO4 (3-) concentration. Such correlations varied depending on the taxonomic level, demonstrating the importance of comprehensive correlation analyses at various taxonomic levels in evaluating the effects of environmental variable factors on prokaryotic community structures. Our findings clarify the distribution patterns of the prokaryotic community composition in plateau lakes at the levels of individual clades as

  12. The fate of the outer plasmasphere

    SciTech Connect

    Elphic, R.C.; Thomsen, M.F.; Borovsky, J.E.

    1997-02-01

    Both the solar wind and the ionosphere contribute to Earth{close_quote}s magnetospheric plasma environment. However, it is not widely appreciated that the plasmasphere is a large reservoir of ionospheric ions that can be tapped to populate the plasma sheet. We employ empirical models of high-latitude ionospheric convection and the geomagnetic field to describe the transport of outer plasmasphere flux tubes from the dayside, over the polar cap and into the magnetotail during the early phases of a geomagnetic storm. We calculate that this process can give rise to high densities of cold plasma in the magnetotail lobes and in the near-Earth plasma sheet during times of enhanced geomagnetic activity, and especially during storms. This model can help explain both polar cap ionization patches and the presence of cold flowing ions downtail.{copyright} 1997 American Geophysical Union

  13. Organic Matter in the Outer Solar System

    NASA Technical Reports Server (NTRS)

    Cruiskshank, Dale P.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    Many solid bodies in the outer Solar System are covered with ices of various compositions, including water, carbon dioxide, methane, nitrogen, and other molecules that are solid at the low temperatures that prevail there. These ices have all been detected by remote sensing observations made with telescopes on Earth, or more recently, spacecraft in orbit (notably Galileo at Jupiter). The data also reveal other solid materials that could be minerals or complex carbon-bearing organic molecules. A study in progress using large ground-based telescopes to acquire infrared spectroscopic data, and laboratory results on the optical properties of complex organic matter, seeks to identify the non-icy materials on several satellites of Saturn, Uranus, and Neptune. The work on the satellites of Saturn is in part preparatory to the Cassini spacecraft investigation of the Saturn system, which will begin in 2004 and extend for four years.

  14. Formation of the outer planets and satellites

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1977-01-01

    A mechanism for the formation of the outer planets is proposed, the basis of which is the idea that the giant planets contain an excess of chemically condensable materials over solar composition. Planetary cores were formed by the clumping together of chemically condensed bodies forming a thin disk in the solar nebula. Gas surrounding a core becomes unstable against collapse onto the core. In the case of Jupiter and Saturn, much of the collapsing gas goes into orbit about the formed planet, forming a relatively thin circumplanetary disks with differential rotation in the prograde sense. For Uranus and Neptune, the dynamical collapse mechanism is unlikely. A disk of gas around Uranus may have been formed during a collision of the protoplanet with a large body. The circumplanetary disks then form the basis for formation of satellite systems, in which the Goldreich-Ward instability mechanism plays a role.

  15. Outer Hair Cell Electromotility in vivo

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, Sripriya; Nuttall, Alfred L.

    2011-11-01

    The effectiveness of outer hair cell (OHC) electro-motility in vivo has been challenged by the expected low-pass filtering of the transmembrane potential due to the cell's own capacitance. The OHC electromotility is characterized here by an electromechanical ratio defined as the ratio of the OHC contraction to the transmembrane potential. This ratio has been measured in isolated cells to be approximately 26 nm/mV. We estimate the OHC electromechanical ratio in vivo from the recently measured displacements of the reticular lamina and the basilar membrane near the 19 kHz characteristic frequency in the basal region of guinea pig cochlea. Our analysis strongly suggests OHC electromotility process is effective for cochlear amplification in vivo at least around the characteristic frequency of the basal location in spite of the low-pass filtering.

  16. Lateral interactions in the outer retina

    PubMed Central

    Thoreson, Wallace B.; Mangel, Stuart C.

    2012-01-01

    Lateral interactions in the outer retina, particularly negative feedback from horizontal cells to cones and direct feed-forward input from horizontal cells to bipolar cells, play a number of important roles in early visual processing, such as generating center-surround receptive fields that enhance spatial discrimination. These circuits may also contribute to post-receptoral light adaptation and the generation of color opponency. In this review, we examine the contributions of horizontal cell feedback and feed-forward pathways to early visual processing. We begin by reviewing the properties of bipolar cell receptive fields, especially with respect to modulation of the bipolar receptive field surround by the ambient light level and to the contribution of horizontal cells to the surround. We then review evidence for and against three proposed mechanisms for negative feedback from horizontal cells to cones: 1) GABA release by horizontal cells, 2) ephaptic modulation of the cone pedicle membrane potential generated by currents flowing through hemigap junctions in horizontal cell dendrites, and 3) modulation of cone calcium currents (ICa) by changes in synaptic cleft proton levels. We also consider evidence for the presence of direct horizontal cell feed-forward input to bipolar cells and discuss a possible role for GABA at this synapse. We summarize proposed functions of horizontal cell feedback and feed-forward pathways. Finally, we examine the mechanisms and functions of two other forms of lateral interaction in the outer retina: negative feedback from horizontal cells to rods and positive feedback from horizontal cells to cones. PMID:22580106

  17. FBL Outer Can Welder Acquisition Software

    SciTech Connect

    Collins, Susan L.

    2004-01-16

    The Outer Can Welder Data Acquisition Software (OCWDAS) was originally developed by SRTC for use at Hanford to assist in the storage of their excess plutonium in the DOE standard 3013 containers until it can be properly dispositioned using one of the approved DOE methods. After Hanford OCWDAS software was the starting point for the new version developed for FB-Line. New graphical display formats and features were added to this software to make it more robust and operator friendly. Several hardware changes were also made at this time and the software was modified to accommodate these as well. During the welding process, critical weld parameters such as weld current and voltage, can give valuable information about the weld. In the past, weld data from the TIG welding process, such as the bagless transfer system in FB-Line, has been monitored using strip chart recorders. The data from the weld process, recorded on the strip chart recorder traces, are reviewed to analyze the weld. The OCWDAS improves this technology by digitizing the weld data which allows for automation of the analysis process. The OCWDAS performs the necessary functions to perform the data acquisition functions during the 3013 Outer Can Welding Process. It is important to monitor the critical weld parameters, current and voltage, during a weld as they can be used to set acceptance criteria for weld acceptance. The software monitors and records the weld current, voltage, and RPM data. It also records the absolute position of the weld head during the weld process from a quadrature encoder. Digital handshaking between the AMI Welding unit and the OCWDAS ensure that both systems are operational and ready prior to the weld initiation taking place.

  18. Nuclear Electric Propulsion for Outer Space Missions

    NASA Technical Reports Server (NTRS)

    Barret, Chris

    2003-01-01

    Today we know of 66 moons in our very own Solar System, and many of these have atmospheres and oceans. In addition, the Hubble (optical) Space Telescope has helped us to discover a total of 100 extra-solar planets, i.e., planets going around other suns, including several solar systems. The Chandra (X-ray) Space Telescope has helped us to discover 33 Black Holes. There are some extremely fascinating things out there in our Universe to explore. In order to travel greater distances into our Universe, and to reach planetary bodies in our Solar System in much less time, new and innovative space propulsion systems must be developed. To this end NASA has created the Prometheus Program. When one considers space missions to the outer edges of our Solar System and far beyond, our Sun cannot be relied on to produce the required spacecraft (s/c) power. Solar energy diminishes as the square of the distance from the Sun. At Mars it is only 43% of that at Earth. At Jupiter, it falls off to only 3.6% of Earth's. By the time we get out to Pluto, solar energy is only .066% what it is on Earth. Therefore, beyond the orbit of Mars, it is not practical to depend on solar power for a s/c. However, the farther out we go the more power we need to heat the s/c and to transmit data back to Earth over the long distances. On Earth, knowledge is power. In the outer Solar System, power is knowledge. It is important that the public be made aware of the tremendous space benefits offered by Nuclear Electric Propulsion (NEP) and the minimal risk it poses to our environment. This paper presents an overview of the reasons for NEP systems, along with their basic components including the reactor, power conversion units (both static and dynamic), electric thrusters, and the launch safety of the NEP system.

  19. The Outer Planetary Mission Design Project

    NASA Astrophysics Data System (ADS)

    Benfield, Michael; Turner, M. W.

    2010-10-01

    With the recent focus from the planetary science community on the outer planets of the solar system, The University of Alabama in Huntsville Integrated Product Team program is embarking on a new challenge to develop an outer planetary mission for the academic year 2010-2011. Currently four bodies are of interest for this mission: Titan, Europa, Triton, and Enceledus, with one body being chosen by the instructors by the beginning of the fall semester. This project will use the 2010 Discovery Announcement of Opportunity as its Request for Proposal (RFP). All of the teams competing in this project will use the AO to respond with a proposal to the instructors for their proposed mission and spacecraft concept. The project employs the two-semester design sequence of the IPT program to provide a framework for the development of this mission. This sequence is divided into four phases. Phase 1 - Requirements Development - focuses on the development of both the scientific and engineering requirements of the mission. During this phase the teams work very closely with the PI organization, represented by the College of Charleston. Phase 2 - Team Formation and Architecture Development - concentrates on the assessment of the overall mission architecture from the launch vehicle to the ground operations of the proposed spacecraft. Phase 3 - System Definition - provides for spacecraft subsystem trade studies and further refinement of the specific spacecraft to meet the scientific requirements and objectives developed in Phase 1. Phase 4 - Design - is the phase where the engineers provide the spacecraft design that is required for the mission of interest. At the conclusion of Phases 2 and 4, an external review board evaluates the proposed designs and chooses one winner of the competition.

  20. Outer Planet Mission Studies Neptune Aerocapture

    NASA Technical Reports Server (NTRS)

    Wercinski, Paul F.; Langhoff, Steven R. (Technical Monitor)

    1997-01-01

    Current and previous studies of orbiter missions to the outer planets have clearly identified high-energy aerocapture as a critical and enabling technology. Aerocapture involves the use of aerodynamic lift to fly a trajectory through a planet's atmosphere to sufficiently decelerate an entry vehicle to capture into planetary orbit. In the past, numerous studies of different configurations of lifting entry vehicles were studied for various planetary orbiter missions which identified aerocapture as a feasible concept yet complex and technically challenging. In order to determine the feasibility of high-speed aerocapture at the outer planets, an accurate trajectory simulation of the flight vehicle is the critical first step in the proposed research. Vehicle response to aerodynamic loading must be predicted accurately in the trajectory simulations. For several Neptune orbiter missions currently under study at the Jet Propulsion Laboratory (JPL), entry velocities relative to the rotating atmosphere ranging from 25 to 30 km/sec, are to be expected. Preliminary trajectory analysis has identified the various flow regimes the entry vehicle is expected to fly in the 8 1% H2 and 19% He atmosphere of Neptune. The size and mass of the vehicle are also determined by the launch vehicle constraints and orbiter spacecraft requirements. For a given baseline arrival conditions of an inertial entry velocity of 28 km/sec and an entry mass of 400 kg, a medium lift (L/D = 1), axisymmetric biconic shaped vehicle was selected in order to satisfy entry corridor width requirements expected for Neptune aerocapture. The analysis summarized in this study indicates that a biconic entry vehicle is a feasible concept for a Neptune aerocapture orbiter mission. The preliminary entry trajectory simulations has demonstrated adequate entry corridor control authority. Furthermore, estimates of the stagnation point heating environment has enabled the preliminary selection of candidate lightweight ceramic

  1. FBL Outer Can Welder Acquisition Software

    Energy Science and Technology Software Center (ESTSC)

    2004-01-16

    The Outer Can Welder Data Acquisition Software (OCWDAS) was originally developed by SRTC for use at Hanford to assist in the storage of their excess plutonium in the DOE standard 3013 containers until it can be properly dispositioned using one of the approved DOE methods. After Hanford OCWDAS software was the starting point for the new version developed for FB-Line. New graphical display formats and features were added to this software to make it moremore » robust and operator friendly. Several hardware changes were also made at this time and the software was modified to accommodate these as well. During the welding process, critical weld parameters such as weld current and voltage, can give valuable information about the weld. In the past, weld data from the TIG welding process, such as the bagless transfer system in FB-Line, has been monitored using strip chart recorders. The data from the weld process, recorded on the strip chart recorder traces, are reviewed to analyze the weld. The OCWDAS improves this technology by digitizing the weld data which allows for automation of the analysis process. The OCWDAS performs the necessary functions to perform the data acquisition functions during the 3013 Outer Can Welding Process. It is important to monitor the critical weld parameters, current and voltage, during a weld as they can be used to set acceptance criteria for weld acceptance. The software monitors and records the weld current, voltage, and RPM data. It also records the absolute position of the weld head during the weld process from a quadrature encoder. Digital handshaking between the AMI Welding unit and the OCWDAS ensure that both systems are operational and ready prior to the weld initiation taking place.« less

  2. Seismic wave speed structure of the Ontong Java Plateau

    NASA Astrophysics Data System (ADS)

    Covellone, Brian M.; Savage, Brian; Shen, Yang

    2015-06-01

    The Ontong Java Plateau (OJP) represents the result of a significant event in the Earth's geologic history. Limited geophysical and geochemical data, as well as the plateau's relative isolation in the Pacific ocean, have made interpretation of the modern day geologic structure and its 120 Ma formation history difficult. Here we present the highest resolution image to date of the wave speed structure of the OJP region. We use a data set that combines Rayleigh waves extracted from both ambient noise and earthquake waveforms and an iterative finite-frequency tomography methodology. The combination of datasets allow us to best exploit the limited station distribution in the Pacific and image wave speed structures between 35 km and 300 km into the Earth. We image a region of fast shear wave speeds, greater than 4.75 km/s, that extends to greater than 100 km beneath the plateau. The wave speeds are similar to as observed in cratonic environments and are consistent with a compositional anomaly that resulted from the residuum of eclogite entrainment during the plateau's formation. The combination of our imaged wave speed structure and previous geochemical work suggest that a surfacing plume head entrained eclogite from the deep mantle and accounts for the anomalous buoyancy characteristics of the plateau and observed fast wave speeds.

  3. Constraints on the early uplift history of the Tibetan Plateau.

    PubMed

    Wang, Chengshan; Zhao, Xixi; Liu, Zhifei; Lippert, Peter C; Graham, Stephan A; Coe, Robert S; Yi, Haisheng; Zhu, Lidong; Liu, Shun; Li, Yalin

    2008-04-01

    The surface uplift history of the Tibetan Plateau and Himalaya is among the most interesting topics in geosciences because of its effect on regional and global climate during Cenozoic time, its influence on monsoon intensity, and its reflection of the dynamics of continental plateaus. Models of plateau growth vary in time, from pre-India-Asia collision (e.g., approximately 100 Ma ago) to gradual uplift after the India-Asia collision (e.g., approximately 55 Ma ago) and to more recent abrupt uplift (<7 Ma ago), and vary in space, from northward stepwise growth of topography to simultaneous surface uplift across the plateau. Here, we improve that understanding by presenting geologic and geophysical data from north-central Tibet, including magnetostratigraphy, sedimentology, paleocurrent measurements, and (40)Ar/(39)Ar and fission-track studies, to show that the central plateau was elevated by 40 Ma ago. Regions south and north of the central plateau gained elevation significantly later. During Eocene time, the northern boundary of the protoplateau was in the region of the Tanggula Shan. Elevation gain started in pre-Eocene time in the Lhasa and Qiangtang terranes and expanded throughout the Neogene toward its present southern and northern margins in the Himalaya and Qilian Shan. PMID:18362353

  4. Constraints on the early uplift history of the Tibetan Plateau

    PubMed Central

    Wang, Chengshan; Zhao, Xixi; Liu, Zhifei; Lippert, Peter C.; Graham, Stephan A.; Coe, Robert S.; Yi, Haisheng; Zhu, Lidong; Liu, Shun; Li, Yalin

    2008-01-01

    The surface uplift history of the Tibetan Plateau and Himalaya is among the most interesting topics in geosciences because of its effect on regional and global climate during Cenozoic time, its influence on monsoon intensity, and its reflection of the dynamics of continental plateaus. Models of plateau growth vary in time, from pre-India-Asia collision (e.g., ≈100 Ma ago) to gradual uplift after the India-Asia collision (e.g., ≈55 Ma ago) and to more recent abrupt uplift (<7 Ma ago), and vary in space, from northward stepwise growth of topography to simultaneous surface uplift across the plateau. Here, we improve that understanding by presenting geologic and geophysical data from north-central Tibet, including magnetostratigraphy, sedimentology, paleocurrent measurements, and 40Ar/39Ar and fission-track studies, to show that the central plateau was elevated by 40 Ma ago. Regions south and north of the central plateau gained elevation significantly later. During Eocene time, the northern boundary of the protoplateau was in the region of the Tanggula Shan. Elevation gain started in pre-Eocene time in the Lhasa and Qiangtang terranes and expanded throughout the Neogene toward its present southern and northern margins in the Himalaya and Qilian Shan. PMID:18362353

  5. Rapid Loss of Lakes on the Mongolian Plateau

    NASA Astrophysics Data System (ADS)

    Tao, S.; Fang, J.; Zhao, X.; Zhao, S.; Shen, H.; Hu, H.; Tang, Z.; Wang, Z.; Guo, Q.

    2015-12-01

    Lakes are widely distributed on the Mongolian Plateau and as critical water sources have sustained Mongolian pastures for hundreds of years. However, the plateau has experienced significant lake shrinkage and grassland degradation during the past several decades. To quantify the changes in all the lakes on the plateau and the associated driving factors, we performed a satellite-based survey using multi-temporal Landsat images from the 1970s to 2000s, combining with ground-based censuses. Our results document a rapid loss of lakes on the plateau in the past decades: the number of lakes with a water surface area >1 km2 decreased from 785 in the late 1980s to 577 in 2010, with a greater rate of decrease (34.0%) in Inner Mongolia of China than in Mongolia (17.6%). This decrease has been particularly pronounced since the late 1990s in Inner Mongolia and the number of lakes >10 km2 has declined by 30.0%. The statistical analyses suggested that in Mongolia precipitation was the dominant driver for the lake changes, while in Inner Mongolia coal mining was most important in its grassland area and irrigation was the leading factor in its cultivated area. The deterioration of lakes is expected to continue in the following decades not only because of changing climate but also increasing exploitation of underground mineral and groundwater resources on the plateau. To protect grasslands and the indigenous nomads, effective action is urgently required to save these valuable lakes from further deterioration.

  6. End member models for Andean Plateau uplift

    NASA Astrophysics Data System (ADS)

    Barnes, J. B.; Ehlers, T. A.

    2008-12-01

    We test whether central Andean Plateau (AP) uplift was fundamentally slow and steady or rapid and recent. These end-member uplift models are evaluated by synthesizing geologic, geomorphic, geochemical, and geophysical observations in the central Andes and presenting a synoptic description of AP development. Results are as follows: AP structural and geophysical studies identify variable shortening magnitudes (530- 150 km) involving cover-to-basement rocks, an isostatically-compensated thick AP crust (80-65 km), high heat flow, and zones of variable velocity and attenuation in the crust and mantle. These observations have invoked interpretations such as a hot/weak lithosphere, partial melt, crustal flow, and even current, localized delamination, but appear to lack strong support for the rapid uplift model which predicts massive late Miocene delamination. AP deformation began ~60-40 Ma and migrated eastward with consistent long-term average rates (~12-8 mm/yr) in Bolivia, favoring the slow uplift model. Volcanic and helium isotope evidence show an AP-wide zone of shallow mantle melting and thin lithosphere that has existed for the last 25 Ma, contrary to the rapid rise model predictions. Uplift constraints advocate a rapid ~2.5 km elevation gain 10-6 Ma, but are equally consistent within error with a more linear rise since >sim25 Ma. Widespread and substantial fluvial incision (2.5-1 km) occurred along the western AP flank since 11-8 Ma which may be associated with surface uplift as proposed by the rapid rise model. However, simulated, AP uplift-induced climate changes suggest a) sizeable corrections to the paleoaltimetry data and b) a climate change trigger for the western AP flank incision, both of which support the slow rise model. From this, we, among other studies, conclude that 1) significant upper-plate deformation within a weak lithosphere is essential to AP growth, 2) AP development has taken significantly longer (>40 Myr since deformation began, >~25 Myr

  7. Teaching Rayleigh-Plateau instabilities in the laboratory

    NASA Astrophysics Data System (ADS)

    Fragkopoulos, A. A.; Ellis, P. W.; Fernandez-Nieves, A.

    2015-09-01

    The breakup of a liquid jet into spherical droplets via the Rayleigh-Plateau instability is a common and fundamental part of fluid mechanics. However, teaching this instability in a laboratory setting is challenging, requiring sophisticated methods to generate and study the jet dynamics. Recently, toroidal droplets were shown to break into one or more spherical droplets in the thin-drop limit via the Rayleigh-Plateau instability. We propose a simple experimental setup to generate toroidal droplets that break up on the order of tens of seconds, allowing for easy video capture using a basic CCD camera. With this setup, it is possible to quantify the Rayleigh-Plateau instability in a pedagogical laboratory setting. In addition, the role of curvature on jet breakup can be explored using thick toroidal droplets. We envision this setup as a powerful teaching tool for one of the most fundamental fluid dynamics processes.

  8. Bedrock geology of the northern Columbia Plateau and adjacent areas

    NASA Technical Reports Server (NTRS)

    Swanson, D. A.; Wright, T. L.

    1978-01-01

    The Columbia Plateau is surrounded by a complex assemblage of highly deformed Precambrian to lower Tertiary continental and oceanic rocks that reflects numerous episodes of continental accretion. The plateau itself is comprised of the Columbia River basalt group formed between about 16.5 x 1 million years B.P. and 6 x 1 million years B.P. Eruptions were infrequent between about 14 and 6 x 1 million years B.P., allowing time for erosion and deformation between successive outpourings. The present-day courses of much of the Snake River, and parts of the Columbia River, across the plateau date from this time. Basalt produced during this waning activity is more heterogeneous chemically and isotopically than older flows, reflecting its prolonged period of volcanism.

  9. CANNIBAL PLATEAU ROADLESS AREA AND POWDERHORN WILDERNESS STUDY AREA, COLORADO.

    USGS Publications Warehouse

    Sharp, William N.; Lane, M.E.

    1984-01-01

    The Cannibal Plateau Roadless Area and the adjoining Powderhorn Wilderness study area are on the Gunnison-Hinsdale County boundary, approximately 50 mi southwest of Gunnison and a few miles east of Lake City. Part of the area has been known as the Powderhorn Primitive Area. The mineral-resource potential involved a basic geologic study, a geophysical survey, and a geochemical survey. No mining districts exist within the two areas, but the Lake City mining district adjoins the Cannibal Plateau Roadless Area at the southwest edge. The mineral-resource survey indicates that the southwest part of the Cannibal Plateau Roadless Area has probable mineral-resource potential, for gold, silver, and molybdenum. There is little promise for the occurrence of mineral and energy resources for the remainder of the areas.

  10. Geologic applications of ERTS images on the Colorado Plateau, Arizona

    NASA Technical Reports Server (NTRS)

    Goetz, A. F. H.; Billingsley, F. C.; Elston, D. P.; Lucchitta, I.; Shoemaker, E. M.

    1974-01-01

    Three areas in central and northern Arizona centered on the (1) Verde Valley, (2) Coconino Plateau, and (3) Shivwits Plateau were studied using ERTS photography. Useful applications results include: (1) upgrading of the existing state geologic map of the Verde Valley region; (2) detection of long NW trending lineaments in the basalt cap SE of Flagstaff which may be favorable locations for drilling for new water supplies; (3) tracing of the Bright Angel and Butte faults to twice their previously known length and correlating the extensions with modern seismic events, showing these faults to be present-day earthquake hazards; (4) discovering and successfully drilling perched sandstone aquifers in the Kaibab Limestone on the Coconino Plateau; and (5) determining the relationship between the Shivwits lavas and the formation of the lower Grand Canyon and showing that the lavas should be an excellent aquifer, as yet untapped.

  11. Fukushima Nuclear Accident Recorded in Tibetan Plateau Snow Pits

    PubMed Central

    Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

    2015-01-01

    The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month. PMID:25658094

  12. The impacts of the summer plateau monsoon over the Tibetan Plateau on the rainfall in the Tarim Basin, China

    NASA Astrophysics Data System (ADS)

    Zhao, Yong; Huang, Anning; Zhou, Yang; Yang, Qing

    2015-08-01

    The impacts of the summer plateau monsoon (PM) over the Tibetan Plateau on summer rainfall over the Tarim Basin in northwest China are investigated, based on the observed rainfall data at 34 stations and the NCEP/NCAR reanalysis data during 1961 to 2007. Results showed that the PM is well correlated to the summer rainfall over the Tarim Basin. Process analysis shows that strong PM corresponds to an anomalous cyclone over the Tibetan Plateau in the middle troposphere and an anomalous anticyclone in the upper troposphere over northwest part of Tibetan Plateau. They result in cold air moving from high latitudes into Central Asia over the western part of Tibetan Plateau. The concurrences of the cooling in the middle-upper troposphere over Central Asia leads to an anomalous cyclone over Central Asia at 500 hPa and the anomalous descending motions prevailing over the cooling region. Associated with this anomaly, there are enhanced southerly winds and corresponding ascending motion over the Tarim Basin located in the east of the cooling region. These processes lead to more summer rainfall over the Tarim Basin.

  13. Corrugated outer sheath gas-insulated transmission line

    DOEpatents

    Kemeny, George A.; Cookson, Alan H.

    1981-01-01

    A gas-insulated transmission line includes two transmission line sections each of which are formed of a corrugated outer housing enclosing an inner high-voltage conductor disposed therein, with insulating support means supporting the inner conductor within the outer housing and an insulating gas providing electrical insulation therebetween. The outer housings in each section have smooth end sections at the longitudinal ends thereof which are joined together by joining means which provide for a sealing fixed joint.

  14. yermak plateau: new geophysical data from its northern part

    NASA Astrophysics Data System (ADS)

    Medow, A.; Jokat, W.

    2003-04-01

    The Yermak Plateau is a relatively young geological feature (about 36 Ma) whose origin is not known in detail. It is situated North of Svalbard between 80 and 82N and betweeen 0 and 10E. It is suggested that excessive magmatism, associated with mantle plume built up the northern part of the Yermak Plateau. In contrast recent observations showed the evidence for non-volcanic breakup of the Yermak Plateau. The southern part of the Yermak Plateau is generally covered by sedimentary deposits more than 1000 m thick. In 2002 the northern part of Yermak Plateau was geophysically explored with the research icebreaker Polarstern. Gravity and seismic data were acquired. The source for the seismic experiments was a 24l-airgun-array. Parallel to the steep angle data acquisition (10 profiles, 600 km) wide-angle data in total five sonobuoys were deployed to determine the sediment and the upper crustal velocities. The aim was to extend the seismic network as far north and east as the ice conditions allow. In the west we found sediment thickness of almost 1300 m and upper crustal velocities of 5.0 km/s, which are in good agreement with results from the southern part. Along two E-W profiles pronounced changes in the steep and wide angle data are observed. After a number of mounds were crossed by the vessel, the seismic reflection data show clear evidence for E-W extension. The basement in this zone is strongly faulted. The seismic velocities also change significantly. For upper crustal layers at depth of 4 km velocities of 6.7 km/s are observed on one sonobouy. This is also the area, where the magnetic anomalies increase in amplitude towards the west. We interprete the presence of the high velocities in the upper crust as indication for a heavily intruded continental crust rather than oceanic crust. Preliminary results from gravity modelling of the northern Yermak Plateau will also be presented.

  15. Transport in the plateau regime in a tokamak pedestal

    SciTech Connect

    Seol, J.; Shaing, K. C.

    2012-07-15

    In a tokamak H-mode, a strong E Multiplication-Sign B flow shear is generated during the L-H transition. Turbulence in a pedestal is suppressed significantly by this E Multiplication-Sign B flow shear. In this case, neoclassical transport may become important. The neoclassical fluxes are calculated in the plateau regime with the parallel plasma flow using their kinetic definitions. In an axisymmetric tokamak, the neoclassical particles fluxes can be decomposed into the banana-plateau flux and the Pfirsch-Schlueter flux. The banana-plateau particle flux is driven by the parallel viscous force and the Pfirsch-Schlueter flux by the poloidal variation of the friction force. The combined quantity of the radial electric field and the parallel flow is determined by the flux surface averaged parallel momentum balance equation rather than requiring the ambipolarity of the total particle fluxes. In this process, the Pfirsch-Schlueter flux does not appear in the flux surface averaged parallel momentum equation. Only the banana-plateau flux is used to determine the parallel flow in the form of the flux surface averaged parallel viscosity. The heat flux, obtained using the solution of the parallel momentum balance equation, decreases exponentially in the presence of sonic M{sub p} without any enhancement over that in the standard neoclassical theory. Here, M{sub p} is a combination of the poloidal E Multiplication-Sign B flow and the parallel mass flow. The neoclassical bootstrap current in the plateau regime is presented. It indicates that the neoclassical bootstrap current also is related only to the banana-plateau fluxes. Finally, transport fluxes are calculated when M{sub p} is large enough to make the parallel electron viscosity comparable with the parallel ion viscosity. It is found that the bootstrap current has a finite value regardless of the magnitude of M{sub p}.

  16. Sedimentary basin framework of Exmouth Plateau, northwest Australia

    SciTech Connect

    Boyd, R.; Exon, N.; Williamson, P.

    1987-05-01

    The Exmouth Plateau is a marginal plateau lying off northwest Australia. Water depths range between 800 m and 4000 m, and the area shallower than 2000 m covers approximately 150,000 km/sup 2/. The plateau consists of rifted and deeply subsided continental crust, with a Phanerozoic sedimentary sequence around 10 km thick, deposited in the Canning and Carnarvon basins. The plateau is separated from the Northwest Shelf by the Kangaroo syncline and is bounded to the north, west, and south by oceanic crust of Cretaceous and Jurassic age. The present structural configuration of Exmouth Plateau was initiated by rifting in the Triassic to Middle Jurassic, followed by northwest-oriented sea floor spreading. The western margin has a normal rifted structure, while the southern margin structure was dominated by transform motion. The complex rifted and sheared northern margin contains at least one crustal block of post-breakup igneous origin. Below a rift onset unconformity of Neocomian age lies a thick Triassic paralic sequence to the south, while farther north the unconformity is of Callovian age and overlies a Jurassic sequence of Tethyan carbonates, coal measures, and volcanics. The post-breakup sequence consists of Late Jurassic-Cenomanian deltaic and shelf clastics, overlain by thin Late Cretaceous-Tertiary shallow marine to pelagic carbonates. Exmouth Plateau therefore represents classic rift to mature ocean stage development of a sediment-starved passive margin. The large fault blocks in the rifted Triassic-Jurassic sequences and large areal closures in the Cretaceous deltas encouraged petroleum exploration over the last two decades. The rifted section was shown to be gas prone, while the overlying section proved to be largely immature.

  17. Tectonics of the Outer Planet Satellites

    NASA Technical Reports Server (NTRS)

    McKinnon, W. B.; Collins, G. C.; Moore, J. M.; Nimmo, F.; Pappalardo, R. T.; Prockter, L. M.; Schenk, P. M.

    2010-01-01

    Tectonic features on the satellites of the outer planets range from the familiar, such as clearly recognizable graben on many satellites, to the bizarre, such as the ubiquitous double ridges on Europa, the twisting sets of ridges on Triton, or the isolated giant mountains rising from Io's surface. All of the large and middle-sized outer planet satellites except Io are dominated by water ice near their surfaces. Though ice is a brittle material at the cold temperatures found in the outer solar system, the amount of energy it takes to bring it close to its melting point is lower than for a rocky body. Therefore, some unique features of icy satellite tectonics may be influenced by a near-surface ductile layer beneath the brittle surface material, and several of the icy satellites may possess subsurface oceans. Sources of stress to drive tectonism are commonly dominated by the tides that deform these satellites as they orbit their primary giant planets. On several satellites, the observed tectonic features may be the result of changes in their tidal figures, or motions of their solid surfaces with respect to their tidal figures. Other driving mechanisms for tectonics include volume changes due to ice or water phase changes in the interior, thermoelastic stress, deformation of the surface above rising diapirs of warm ice, and motion of subsurface material toward large impact basins as they fill in and relax. Most satellites exhibit evidence for extensional deformation, and some exhibit strike-slip faulting, whereas contractional tectonism appears to be rare. Io s surface is unique, exhibiting huge isolated mountains that may be blocks of crust tilting and foundering into the rapidly emptying interior as the surface is constantly buried by deposits from hyperactive volcanoes. Of the satellites, diminutive Enceladus is spectacularly active; its south polar terrain is a site of young tectonism, copious heat flow, and tall plumes venting into space. Europa's surface is

  18. Biogenesis of outer membranes in Gram-negative bacteria.

    PubMed

    Tokuda, Hajime

    2009-03-23

    The outer membrane, an essential organelle of Gram-negative bacteria, is composed of four major components: lipopolysaccharide, phospholipids, beta-barrel proteins, and lipoproteins. The mechanisms underlying the transport of these components to outer membranes are currently under extensive examination. Among them, the sorting of lipoproteins to the outer membrane of Escherichia coli has been clarified in detail. The Lol system, composed of five proteins, catalyzes outer membrane sorting of lipoproteins. Various Lpt proteins have recently been identified as factors involved in the transport of lipopolysaccharide to the outer membrane, although the mechanism remains largely unknown. Proteins with alpha-helical membrane spanning segments are found in the inner membrane, whereas amphipathic beta-barrel proteins span the outer membrane. These beta-barrel proteins are inserted into the outer membranes through a central core protein BamA (YaeT) with the help of four outer membrane lipoproteins. In contrast, little is known about how phospholipids are transported to the outer membrane. PMID:19270402

  19. Ion plateau transport near the tokamak magnetic axis

    SciTech Connect

    Shaing, K.C.; Hazeltine, R.D.

    1998-04-01

    Conventional neoclassical transport theory does not pertain near the magnetic axis, where orbital variation of the minor radius and the poloidal field markedly change the nature of guiding-center trajectories. Instead of the conventional tokamak banana-shaped trajectories, near-axis orbits, called potato orbits, are radially wider and lead to distinctive kinetic considerations. Here it is shown that there is a plateau regime for the near-axis case; the corresponding potato-plateau ion thermal conductivity is computed. {copyright} {ital 1998 American Institute of Physics.}

  20. Mineralogy and geochemistry of vanadium in the Colorado Plateau

    USGS Publications Warehouse

    Weeks, A.D.

    1961-01-01

    The chief domestic source of vanadium is uraniferous sandstone in the Colorado Plateau. Vanadium is 3-, 4-, or 5-valent in nature and, as oxides or combined with other elements, it forms more than 40 minerals in the Plateau ores. These ores have been studied with regard to the relative amounts of vanadium silicates and oxide-vanadates, uranium-vanadium ratios, the progressive oxidation of black low-valent ores to high-valent carnotite-type ores, and theories of origin. ?? 1961.

  1. Geologic Mapping of the Aristarchus Plateau Region on the Moon

    NASA Technical Reports Server (NTRS)

    Lough, T. A.; Gregg, T. K. P.; Yingst, Aileen R.

    2010-01-01

    Aristarchus plateau (25 N, 40 W) is a volcanologically diverse region containing sinuous rilles, volcanic depressions, mare material of various ages - including a candidate for the youngest mare unit on the lunar surface - pyroclastic deposits, and material of possible highland origin [1-5]. Here, we present preliminary mapping of a 13deg x 10deg area around Aristarchus plateau [6]. Interpretations of the region s volcanic evolution have implications for the global history of lunar volcanism, the crustal and mantle development of the Moon, and may ultimately help support successful lunar exploration [7].

  2. The Magnetic Field in the Outer Heliosphere

    NASA Technical Reports Server (NTRS)

    Suess, S. T.

    2004-01-01

    One of the great achievements of Parker was the prediction that the solar magnetic field would be drawn into Archimedian spirals as it is carried away from the Sun by the solar wind. This prediction has been amply confirmed by many in situ measurements in the intervening four decades. But, Parker made his prediction for a solar wind that expands into infinite space while we now know that the local interstellar medium (LISM) is far from empty and, in fact, confines the solar wind to a finite volume, known as the heliosphere, that extends to approximately 100 AU in the upstream direction (the solar system is moving through the LISM). Voyagers 1/2, presently at -80 AU, are approaching the upstream boundaries of the heliosphere and returning data on the properties of the magnetic field. This is important for understanding how galactic cosmic rays (GCRs) reach the Earth. Voyagers show that the IMF at 10-80 AU behaves much as Parker predicted - with two important exceptions. This is not surprising since the field is essentially passively advected by the solar wind out to 80 AU. But, new models say that nearer the heliosphere boundaries the field plays a major role in the solar wind-LISM interaction. However, of the many physical ingredients that constitute the outer heliosphere, the magnetic field poses some of the most interesting and difficult numerical modeling problems. Presently, only a few results have been published and much remains to be done. Here I will summarize the expected and measured behavior of the magnetic field at 80 AU. Then I will describe modeling predictions beyond 80 AU: magnetic "tornadoes", polarity envelopes, the Axford-Cranfill effect, inner and outer magnetic walls and more. I will also list what I believe to be important new modeling objectives. Finally, I will speculate on what is happening with the magnetic field near the nose of the heliosphere. My conclusion is that models of GCR modulation rarely incorporate even crudely realistic

  3. The Spite Lithium Plateau: Ultrathin but Postprimordial

    NASA Astrophysics Data System (ADS)

    Ryan, Sean G.; Norris, John E.; Beers, Timothy C.

    1999-10-01

    We have studied 23 very metal-poor field turnoff stars, specifically chosen to enable a precise measurement of the dispersion in the lithium abundance of the Spite Li plateau. We concentrated on stars having a narrow range of effective temperature and very low metallicities ([Fe/H]<~-2.5) to reduce the effects of systematic errors and have made particular efforts to minimize random errors. A typical statistical error for our abundances is 0.033 dex (1 σ), which represents a factor of 2 improvement on most previous studies. Our sample does not exhibit a trend with effective temperature, although the temperature range is limited. However, for -3.6<[Fe/H]<-2.3 we do recover a dependence on metallicity at dA(Li)/d[Fe/H]=0.118+/-0.023 (1 σ) dex per dex, almost the same level as discussed previously. Earlier claims for a lack of dependence of A(Li) on abundance are shown to have arisen probably from noisier estimates of effective temperatures and metallicities, which have erased the real trend. The dependence is concordant with theoretical predictions of Galactic chemical evolution (GCE) of Li (even in such metal-poor stars) and with the published level of 6Li in two of the stars of our sample, which we use to infer the GCE 7Li contribution. One of the 23 stars, G186-26, was known already to be strongly Li-depleted. Of the remaining 22 objects, 21 have abundances consistent with an observed spread about the metallicity trend of a mere 0.031 dex (1 σ). Because the formal errors are 0.033 dex, we conclude that the intrinsic spread is effectively zero at the very metal-poor halo turnoff. This is established at much higher precision than previous studies (~0.06-0.08 dex). The essentially zero intrinsic spread leads to the conclusion that either these stars have all changed their surface Li abundances very uniformly, or else they exhibit close to the primordial abundance sought for its cosmological significance. We cannot rule out a uniform depletion mechanism, but economy

  4. Is the Asian lithosphere underthrusting beneath northeastern Tibetan Plateau? Insights from seismic receiver functions

    NASA Astrophysics Data System (ADS)

    Shen, Xuzhang; Yuan, Xiaohui; Liu, Mian

    2015-10-01

    Whether or not the Asian lithosphere has underthrusted beneath the Tibetan Plateau is important for understanding the mechanisms of the plateau's growth. Using data from the permanent seismic stations in northeastern Tibetan Plateau, we studied seismic structures of the lithosphere and upper mantle across the plateau's northeastern margin using P and S receiver functions. The migrated P- and S-receiver function images reveal a thick crust and a diffuse lithosphere-asthenosphere boundary (LAB) beneath the Tibetan Plateau, contrasting sharply with the relatively thin crust and clear, sharp LAB under the bounding Asian blocks. The well-defined LAB under the Asian blocks tilts toward but does not extend significantly under the Tibetan Plateau; this is inconsistent with the model of Asian mantle lithosphere underthrusting beneath the Tibet Plateau. Instead, our results indicate limited, passive deformation of the bounding Asian lithosphere as it encounters the growing Tibetan Plateau.

  5. Neogene Topography And Precipitation Patterns Of The Central Anatolian Plateau

    NASA Astrophysics Data System (ADS)

    Mulch, A.; Mikes, T.; Schemmel, F.; Rojay, B.

    2010-12-01

    Long-term stable isotope records of terrestrial environments represent increasingly important tools for tectonic, paleoaltimetric, and paleoclimatic reconstructions within continental interiors. A rapidly growing number of studies within the Earth’s major mountain ranges demonstrates that the growth of topography and orogenic plateaus profoundly influences local, regional, and hemispheric climate and hence precipitation patterns while regional surface uplift patterns are intimately linked to plate-scale geodynamic processes. In contrast, such records are almost absent for the Near East and the Turkish-Iranian plateau, an important topographic element in the Alpine-Himalayan chain and an area most likely to be strongly affected by future climate change and water scarcity. Our objective is to assess the role of orographic factors that have governed the distribution (and isotopic composition) of precipitation across the central Anatolian plateau (CAP, Turkey) from the Neogene to recent. Such data are fundamental for our understanding of the geodynamic and sedimentary history of orogenic plateaus in general and for the role of surface uplift along the plateau margins in the Pontide and Tauride mountains. We present oxygen, carbon, and hydrogen isotope data from Neogene-to-recent fluvio-lacustrine and pedogenic environments, stream and lake waters of the CAP with the ultimate aim of reconstructing past precipitation changes, plateau aridification and ideally Neogene surface uplift histories. Our approach is to cross-calibrate modern patterns of isotopes (oxygen and hydrogen) in precipitation with pedogenic carbonate oxygen and carbon isotope data across topographic barriers that today strongly control the distribution of rainfall along the plateau margins and within the plateau interior. We then compare these patterns with Miocene-to-Pleistocene lacustrine and pedogenic records to assess a) the role of late Neogene (ca. 8-0 Ma) surface uplift in the Taurus mountains

  6. Multispectral Mosaic of the Aristarchus Crater and Plateau

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Aristarchus region is one of the most diverse and interesting areas on the Moon. About 500 Clementine images acquired through three spectral filters (415, 750, and 1000 nm) were processed and combined into a multispectral mosaic of this region. Shown here is a color-ratio composite, in which the 750/415 ratio controls the red-channel brightness, it inverse (415/750) controls the blue, and the 750/1000 ratio controls the green. Color ratios serve to cancel out the dominant brightness variations and topographic shading, thus isolating the color differences related to composition or mineralogy. The Aristarchus plateau is a rectangular, elevated crustal block about 200 km across, surrounded by the vast mare lava plains of Oceanus Procellarum. Clementine altimetry shows that the plateau is a tilted slab sloping down to the northwest, that rises more than 2 km above Oceanus Procellarum on its southeastern margin. The plateau was probably uplifted, tilted, and fractured by the Imbrium basin impact, which also deposited hummocky ejecta on the plateau surface. The plateau has experienced intense volcanic activity, both effusive and explosive. It includes the densest concentration of lunar sinuous rilles, including the largest known, Vallis Schroteri, which is about 160 km long, up to 11 km wide, and 1 km deep. The rilles in this area begin at 'cobra-head' craters, which are the apparent vents for low-viscosity lavas that formed vents for 'dark mantling' deposit covering the plateau and nearby areas to the north and east. This dark mantling deposit probably consists primarily of iron-rich glass spheres (pyroclastics or cinders), and has a deep red color on this image. Rather than forming cinder cones as on Earth, the lower gravity and vacuum of the Moon allows the pyroclastics to travel much greater heights and distances, thus depositing an extensive regional blanket. The Aristarchus impact occurred relatively recently in geologic time, after the Copernicus impact but

  7. Orogenic plateau growth: Expansion of the Turkish-Iranian Plateau across the Zagros fold-and-thrust belt

    NASA Astrophysics Data System (ADS)

    Allen, M. B.; Saville, C.; Blanc, E. J.-P.; Talebian, M.; Nissen, E.

    2013-03-01

    This paper shows how the Turkish-Iranian Plateau grows laterally by incrementally incorporating adjacent parts of the Zagros fold-and-thrust belt. The limit of significant, seismogenic, thrusting in the Zagros (Mw > 5) occurs close to the regional 1250 m elevation contour. The seismicity cutoff is not a significant bedrock geology boundary. Elevations increase northward, toward regional plateau elevations of ~2 km, implying that another process produced the extra elevation. Between the seismogenic limit of thrusting and the suture, this process is a plausibly ductile thickening of the basement, suggesting depth-dependent strain during compression. Similar depth-dependant crustal strain may explain why the Tibetan plateau has regional elevations ~1500 m greater than the elevation limit of seismogenic thrusting at its margins. We estimate ~68 km shortening across the Zagros Simply Folded Belt in the Fars region, and ~120 km total shortening of the Arabian plate. The Dezful Embayment is a low strain zone in the western Zagros. Deformation is more intense to its northeast, in the Bakhtyari Culmination. The orogenic taper (across strike topographic gradient) across the Dezful Embayment is 0.0004, and across the Bakhtyari Culmination, 0.022. Lateral plateau growth is more pronounced farther east (Fars), where a more uniform structure has a taper of ~0.010 up to elevations of ~1750 m. A >100 km wide region of the Zagros further northeast has a taper of 0.002 and is effectively part of the Turkish-Iranian Plateau. Internal drainage enhances plateau development but is not a pre-requisite. Aspects of the seismicity, structure, and geomorphology of the Zagros do not support critical taper models for fold-and-thrust belts.

  8. Infrared observations of outer planet satellites

    NASA Technical Reports Server (NTRS)

    Johnson, T. V.

    1988-01-01

    This task supports IR observations of the outer planet satellites. These data provide vital information about the thermophysical properties of satellite surfaces, including internal heat sources for Io. Observations include both broad and narrow band measurementsin the 2 to 20 micrometer spectral range. The program in the last year has aimed at obtaining lonitude coverage on Io to establish stability of hot spot patterns previously reported. Several runs produced the most complete data set for an apparition since the start of the program. Unfortunately, bad weather limited coverage of key longitude ranges containing the largest known hot spot Loki. Among the preliminary results is the observation of an outburst in Io's thermal flux that was measured at 4.8, 8.7 and 20 micrometer. Analysis of the data has given the best evidence to date of silicate volcanism on Io; this is one of the most significant pieces of the puzzle as to the relative roles of silicate and sulfur volcanism on Io. Researchers are collaborating with J. Goguen (NRC RRA to finish reduction of mutual event data, which have already improved ephermeris information for the satellites. The data appear to place significant limits on the characteristics of any leading side hot spots.

  9. Bacterial Outer Membrane Vesicles and Vaccine Applications

    PubMed Central

    Acevedo, Reinaldo; Fernández, Sonsire; Zayas, Caridad; Acosta, Armando; Sarmiento, Maria Elena; Ferro, Valerie A.; Rosenqvist, Einar; Campa, Concepcion; Cardoso, Daniel; Garcia, Luis; Perez, Jose Luis

    2014-01-01

    Vaccines based on outer membrane vesicles (OMV) were developed more than 20 years ago against Neisseria meningitidis serogroup B. These nano-sized structures exhibit remarkable potential for immunomodulation of immune responses and delivery of meningococcal antigens or unrelated antigens incorporated into the vesicle structure. This paper reviews different applications in OMV Research and Development (R&D) and provides examples of OMV developed and evaluated at the Finlay Institute in Cuba. A Good Manufacturing Practice (GMP) process was developed at the Finlay Institute to produce OMV from N. meningitidis serogroup B (dOMVB) using detergent extraction. Subsequently, OMV from N. meningitidis, serogroup A (dOMVA), serogroup W (dOMVW), and serogroup X (dOMVX) were obtained using this process. More recently, the extraction process has also been applied effectively for obtaining OMV on a research scale from Vibrio cholerae (dOMVC), Bordetella pertussis (dOMVBP), Mycobacterium smegmatis (dOMVSM), and BCG (dOMVBCG). The immunogenicity of the OMV has been evaluated for specific antibody induction, and together with functional bactericidal and challenge assays in mice has shown their protective potential. dOMVB has been evaluated with non-neisserial antigens, including with a herpes virus type 2 glycoprotein, ovalbumin, and allergens. In conclusion, OMV are proving to be more versatile than first conceived and remain an important technology for development of vaccine candidates. PMID:24715891

  10. Outer Space is not Empty Space

    NASA Astrophysics Data System (ADS)

    Johnson, W.; Pratap, P.; Riegel, R.

    2004-12-01

    Outer Space Is Not Empty Space is a learning unit that focuses on increasing comprehension of Astronomy, Chemistry, Physics, Physical Science, and Earth & Space science. It was designed as a self paced study with some teacher oversight. The unit was a result of an NSF funded Research Experiences for Teachers program at MIT Haystack Observatory. The educational vehicle used in the unit is the Web Quest which consists of several Power Point presentations within four main topics in Radio Astronomy: Introduction, Light, Matter, and the Atmosphere. These Web Quests are a self paced series of educational materials that encourages the student to learn on his or her own. They consist of informational web sites placed within a Power Point presentation. They are not designed to be teacher classroom presentations since the paths taken by the student in the Power Points are nonlinear. Each Power Point presentations comes with an assessment to evaluate the students' understanding of the material. One of the goals of this learning unit is to encourage teacher and student use of two unique learning opportunities: the Small Radio Telescope (SRT) and remote use of the Haystack 37m Radio Telescope. The SRT was designed by engineers and scientists at M.I.T.s Haystack Observatory specifically for student use at the University or Secondary School level. The 37-m telescope is available via remote operation for educational projects. Descriptions of both instruments can be found at the MIT Haystack Observatory web site:

  11. The Outer Heliosphere: The Next Frontier

    NASA Astrophysics Data System (ADS)

    Heber, B.; Zank, G. P.

    Only a few decades after the formulation of the concept of a continuous solar corpus- cular radiation by Ludwig Biermann and a solar wind by Eugene Parker, heliospheric physics has evolved into an important branch of astrophysical research. The solar wind forms a bubble, called the heliosphere, in the local interstellar medium, within which the solar system resides and whose size and properties are determined by the manner in which the solar wind and the partially ionized local interstellar medium are coupled. In the last decade, great progress has been made in our understanding of the physical processes thought to describe the outer heliosphere. Numerous spacecraft missions have increased our knowledge about the large-scale structure, the properties, and the character of the heliosphere tremendously. of these, the ageing spacecraft Voyager 1,2 might encounter the inner border of the heliospheric boundary region in the not too distant future. Now, at the beginning of a new millenium, it seems possible, by newly developed technologies to send an interstellar probe beyond the boundaries of the he- liosphere, in order to explore the local interstellar medium in situ. We shall review our basic understanding of global heliospheric structure, emphasizing the importance of the LISM-solar wind coupling, emphasizing the demands and constraints that this places on a mission to the edge of interstellar space.

  12. The Outer Heliosphere: The Next Frontiers

    NASA Astrophysics Data System (ADS)

    Scherer, K.; Fichtner, Horst; Fahr, Hans Jörg; Marsch, Eckart

    The 11th COSPAR Colloquium "The Outer Heliosphere: The Next Frontiers" was held in Potsdam, Germany, from July 24 to 28, 2000, and is the second dedicated to this subject after the first one held in Warsaw, Poland in 1989. Roughly a century has passed after the first ideas by Oliver Lodge, George Francis Fitzgerald and Kristan Birkeland about particle clouds emanating from the Sun and interacting with the Earth environment. Only a few decades after the formulation of the concepts of a continuous solar corpuscular radiation by Ludwig Bierman and a solar wind by Eugene Parker, heliospheric physics has evolved into an important branch of astrophysical research. Numerous spacecraft missions have increased the knowledge about the heliosphere tremendously. Now, at the beginning of a new millenium it seems possible, by newly developed propulasion technologies to send a spacecraft beyond the boundaries of the heliosphere. Such an Interstellar Proce will start the in-situ exploration of interstellar space and, thus, can be considered as the first true astrophysical spacecraft. The year 2000 appeared to be a highly welcome occassion to review the achievements since the last COSPAR Colloquia 11 years ago, to summarize the present developments and to give new impulse for future activities in heliospheric research.

  13. Bacterial outer membrane vesicles and vaccine applications.

    PubMed

    Acevedo, Reinaldo; Fernández, Sonsire; Zayas, Caridad; Acosta, Armando; Sarmiento, Maria Elena; Ferro, Valerie A; Rosenqvist, Einar; Campa, Concepcion; Cardoso, Daniel; Garcia, Luis; Perez, Jose Luis

    2014-01-01

    Vaccines based on outer membrane vesicles (OMV) were developed more than 20 years ago against Neisseria meningitidis serogroup B. These nano-sized structures exhibit remarkable potential for immunomodulation of immune responses and delivery of meningococcal antigens or unrelated antigens incorporated into the vesicle structure. This paper reviews different applications in OMV Research and Development (R&D) and provides examples of OMV developed and evaluated at the Finlay Institute in Cuba. A Good Manufacturing Practice (GMP) process was developed at the Finlay Institute to produce OMV from N. meningitidis serogroup B (dOMVB) using detergent extraction. Subsequently, OMV from N. meningitidis, serogroup A (dOMVA), serogroup W (dOMVW), and serogroup X (dOMVX) were obtained using this process. More recently, the extraction process has also been applied effectively for obtaining OMV on a research scale from Vibrio cholerae (dOMVC), Bordetella pertussis (dOMVBP), Mycobacterium smegmatis (dOMVSM), and BCG (dOMVBCG). The immunogenicity of the OMV has been evaluated for specific antibody induction, and together with functional bactericidal and challenge assays in mice has shown their protective potential. dOMVB has been evaluated with non-neisserial antigens, including with a herpes virus type 2 glycoprotein, ovalbumin, and allergens. In conclusion, OMV are proving to be more versatile than first conceived and remain an important technology for development of vaccine candidates. PMID:24715891

  14. Outer membrane vesicles as platform vaccine technology

    PubMed Central

    Stork, Michiel; van der Ley, Peter

    2015-01-01

    Abstract Outer membrane vesicles (OMVs) are released spontaneously during growth by many Gram‐negative bacteria. They present a range of surface antigens in a native conformation and have natural properties like immunogenicity, self‐adjuvation and uptake by immune cells which make them attractive for application as vaccines against pathogenic bacteria. In particular with Neisseria meningitidis, they have been investigated extensively and an OMV‐containing meningococcal vaccine has recently been approved by regulatory agencies. Genetic engineering of the OMV‐producing bacteria can be used to improve and expand their usefulness as vaccines. Recent work on meningitis B vaccines shows that OMVs can be modified, such as for lipopolysaccharide reactogenicity, to yield an OMV product that is safe and effective. The overexpression of crucial antigens or simultaneous expression of multiple antigenic variants as well as the expression of heterologous antigens enable expansion of their range of applications. In addition, modifications may increase the yield of OMV production and can be combined with specific production processes to obtain high amounts of well‐defined, stable and uniform OMV particle vaccine products. Further improvement can facilitate the development of OMVs as platform vaccine product for multiple applications. PMID:26912077

  15. Statistics of the outer radiation belt

    SciTech Connect

    Rodgers, D.J.; Johnstone, A.D.

    1996-07-01

    The highly variable electron flux levels in the outer radiation belt come about by competition between time-dependent source and loss mechanisms. In order to identify some of the different mechanisms involved, we examine the statistics of the variability of fluxes at geostationary orbit. Data from the SEM-2 analyzer on Meteosat-3 and from GOES-7 are used. Correlation analysis is used to find time-delays between changes in flux at different energies. We see that low energy flux is added to this region during sub-storms and that higher energy fluxes appear after 2 or 3 days. Whilst the timescale for this process is brief compared to a complete cycle of the {open_quote}Recirculation{close_quote} energization process, it is consistent with the timescale of its final step{endash}outward radial diffusion. By isolating periods when no new injection of plasma occurs, we make an assessment of flux loss rates in a quiet magnetosphere. {copyright} {ital 1996 American Institute of Physics.}

  16. THE OUTER MAGNETIC FIELD OF L183

    SciTech Connect

    Clemens, Dan P.

    2012-03-20

    The L183 (= L134N) dark molecular cloud has been probed using deep near-infrared imaging polarimetry of stars to beyond 14 mag in H band (1.6 {mu}m), using the Mimir instrument on the 1.83 m Perkins Telescope. Nearly 400 arcmin{sup 2} were surveyed, including the dense core in L183, as seen in WISE Band 3 (12 {mu}m) extinction, and the near surroundings, revealing 35 stars with either detected polarizations or significant upper limits. Stars with detected polarizations are reddened if closer than 8 arcmin (0.25 pc at the 110 pc cloud distance) and unreddened beyond. The polarimetric sample probes as close to the core as 3 arcmin (0.1 pc), where A{sub V} {approx} 14 mag. Compared to the relatively unextincted surrounding stars, the reddened stars show no increase in polarization with extinction, suggesting that all of the polarization is induced in the outer layers of the cloud. This 0.25 pc radius envelope magnetic field does show a strong interaction with the L183 dark cloud. The envelope field is also virtually perpendicular, on the plane of the sky, to the field seen at 850 {mu}m, though more closely aligned with the rotation axis of the dense gas core. The physical size scale at which the envelope and the core magnetic fields either decouple from each other or strongly modify their directions must be inside the 0.1 pc region probed here.

  17. Detail studies of the physical properties in the outer regions of galaxy clusters using Suzaku observations

    NASA Astrophysics Data System (ADS)

    Babyk, Yu. V.

    2016-06-01

    A detailed physical analysis of five nearby galaxy clusters using Suzaku observationsis presented. The low and stable level of the instrumental background at large radii facilitate the determination of the main physical characteristics in clusters at the virial radius. The temperatures, metal abundances, and entropy profiles have been constructed out to the outskirts of the clusters. The temperature profiles all display the same shape, with a negative gradient towards to the center and a flat outer plateau. The strong temperature gradients in the central parts of the clusters are usually associated with strong peaks of the surface brightness profiles. The temperature systematically decrease outward from the central regions, by a factor of three at and slightly beyond the cluster outskirts. The temperature profiles are compared with profiles predicted by N-body and hydrodynamical simulations obtained using several numerical algorithms. The slopes in the observed and simulated temperature profiles are consistent with each other in the cluster outskirts. The central regions of the clusters are characterized by low entropy and high metallicity. The possible influence of cool cores on the cluster outskirts is also discussed. The total mass profiles were determined using the observed gas-density and temperature profiles, assuming hydrostatic equilibriumand spherical symmetry. The gas-density profiles were fitted using an improved three-dimensional model to fit the inner and outer regions of the cluster independently. The total mass profiles were described using an NFW model out to R 200. The measurements show clear evidence for universality of the total mass distribution. The scaled mass profiles in units of R 200 and M 200 display a dispersion of ~15% at 0.1 R 200. The fraction of gas out to R 200 was also found.

  18. Proceedings of the second biennial conference on research in Colorado Plateau National Parks

    USGS Publications Warehouse

    1995-01-01

    On 25-28 October 1993 in Flagstaff, Arizona, the National Biological Service Colorado Plateau Research Station (formerly National Park Service Cooperative Park Studies Unit) and Northern Arizona University hosted the Second Biennial Conference of Research on the Colorado Plateau. The conference theme focused on research, inventory, and monitoring on the federal, state, and private lands in the Colorado Plateau biogeographic province.

  19. The Colorado Plateau IV: shaping conservation through science and management

    USGS Publications Warehouse

    Wakeling, Brian F.; Sisk, Thomas D.

    2010-01-01

    Roughly centered on the Four Corners region of the southwestern United States, the Colorado Plateau covers some 130,000 square miles of sparsely vegetated plateaus, mesas, canyons, arches, and cliffs in Arizona, Utah, Colorado, and New Mexico. With elevations ranging from 3,000 to 14,000 feet, the natural systems found within the plateau are dramatically varied, from desert to alpine conditions. This book focuses on the integration of science and resource management issues in this unique and highly varied environment. Broken into three subsections, this volume addresses conservation biology, biophysical resources, and inventory and monitoring concerns. The chapters range in content, addressing conservation issues–past, present, and future–on the Colorado Plateau, measurement of human impacts on resources, grazing and wildland-urban interfaces, and tools and methods for monitoring habitats and species. An informative read for people interested in the conservation and natural history of the region, the book will also serve as a valuable reference for those people engaged in the management of cultural and biological resources of the Colorado Plateau, as well as scientists interested in methods and tools for land and resource management throughout the West.

  20. Mapping risk of plague in Qinghai-Tibetan Plateau, China

    PubMed Central

    2014-01-01

    Background Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low incidence but high mortality, which presents unique surveillance and public health challenges, because early detection through surveillance may not always be feasible and infrequent clinical cases may be misdiagnosed. Methods Based on plague surveillance data and environmental variables, Maxent was applied to model the presence probability of plague host. 75% occurrence points were randomly selected for training model, and the rest 25% points were used for model test and validation. Maxent model performance was measured as test gain and test AUC. The optimal probability cut-off value was chosen by maximizing training sensitivity and specificity simultaneously. Results We used field surveillance data in an ecological niche modeling (ENM) framework to depict spatial distribution of natural foci of plague in Qinghai-Tibetan Plateau. Most human-inhabited areas at risk of exposure to enzootic plague are distributed in the east and south of the Plateau. Elevation, temperature of land surface and normalized difference vegetation index play a large part in determining the distribution of the enzootic plague. Conclusions This study provided a more detailed view of spatial pattern of enzootic plague and human-inhabited areas at risk of plague. The maps could help public health authorities decide where to perform plague surveillance and take preventive measures in Qinghai-Tibetan Plateau. PMID:25011940

  1. Behavior of Colorado Plateau uranium minerals during oxidation

    USGS Publications Warehouse

    Garrels, Robert Minard; Christ, C.L.

    1956-01-01

    Uranium occurs as U(VI) and U(IV) in minerals of the Colorado Plateau ores. The number of species containing U(VI) is large, but only two U(IV) minerals are known from the Plateau: uraninite, and oxide, and coffinite, a hydroxy-silicate. These oxidize to yield U(VI) before reacting significantly with other mineral constituents. Crystal-structure analysis has shown that U(VI) invariable occurs as uranyl ion, UO2+2. Uranyl ion may form complex carbonate or sulfate ions with resulting soluble compounds, but only in the absence of quinquevalent vanadium, arsenic, or phosphorous. In the presence of these elements in the +5 valence state, the uranyl ion is fixed in insoluble layer compounds formed by union of uranyl ion with orthovanadate, orthophosphate, or orthoarsenate. Under favorable conditions UO2+2 may react to form the relatively insoluble rutherfordine, UO2CO3, or hydrated uranyl hydroxides. These are rarely found on the Colorado Plateau as opposed to their excellent development in other uraniferous areas, a condition which is apparently related to the semiarid climate and low water table of the Plateau. Uranium may also be fixed as uranyl silicate, but little is known about minerals of this kind. In the present study emphasis has been placed on a detailing of the chemical and crystal structural changes which occur in the oxidation paragenetic sequence.

  2. Structural model of the Balkassar area, Potwar Plateau, Pakistan

    NASA Astrophysics Data System (ADS)

    Iqbal, Shahid; Akhter, Gulraiz; Bibi, Sehrish

    2015-11-01

    Balkassar is an important hydrocarbon producing area of the Potwar Plateau, Pakistan. Two-dimensional seismic reflection data of the area revealed tectonically controlled, distinct episodes of (1) normal faulting in the basement followed by (2) reverse faulting in the cover sequence. Himalayan orogeny and associated diapirism of the Precambrian Salt Range Formation have produced many salt-cored anticlines in the Potwar Plateau, and one such salt-cored anticline is present in the Balkassar. This anticline has NE-SW-oriented axis, and both the SE and NW limbs are bounded by reverse faults. The basement normal faults indicate Jurassic rifting and splitting of Pangaea. We interpret reverse faults with dip angles of about 60°-75° in the cover sequence, having both hinterland and foreland vergence. Both NW- and SE-dipping faults are present in contrast to the only southward-directed thrusts of previous models. Duplexes and triangle zones, which are common in the northern part of the Potwar Plateau, are not developed in the Balkassar area due to comparatively less crustal shortening in the area. The present interpretation can help in understanding the complex structures in other parts of the Potwar Plateau for hydrocarbons exploration and also in deformed foreland basins worldwide that display similar characteristics but are considered to be dominated by low-angle thrust tectonics.

  3. Deep mantle forces and the uplift of the Colorado Plateau

    SciTech Connect

    Moucha, R; Forte, A M; Rowley, D B; Mitrovica, J X; Simmons, N A; Grand, S P

    2009-06-23

    Since the advent of plate tectonics, it has been speculated that the northern extension of the East Pacific Rise, specifically its mantle source, has been over-ridden by the North American Plate in the last 30 Myrs. Consequently, it has also been postulated that the opening of the Gulf of California, the extension in the Basin and Range province, and the uplift of the Colorado Plateau are the resulting continental expressions of the over-ridden mantle source of the East Pacific Rise. However, only qualitative models based solely on surface observations and heuristic, simplified conceptions of mantle convection have been used in support or against this hypothesis. We introduce a quantitative model of mantle convection that reconstructs the detailed motion of a warm mantle upwelling over the last 30 Myrs and its relative advance towards the interior of the southwestern USA. The onset and evolution of the crustal uplift in the central Basin and Range province and the Colorado Plateau is determined by tracking the topographic swell due to this mantle upwelling through time. We show that (1) the extension and magmatism in the central Basin and Range province between 25 and 10 Ma coincides with the reconstructed past position of this focused upwelling, and (2) the southwestern portion of the Colorado Plateau experienced significant uplift between 10 Ma and 5 Ma that progressed towards the northeastern portion of the plateau. These uplift estimates are consistent with a young, ca. 6 Ma, Grand Canyon model and the recent commencement of mafic magmatism.

  4. Nitrogen loss from windblown agricultural soils in the Columbia Plateau

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion of agricultural soils can degrade both air quality and soil productivity in the Columbia Plateau of the Pacific Northwest United States. Soils in the region contain fine particles that, when suspended, are highly susceptible to long range transport in the atmosphere. Nitrogen (N) associ...

  5. Factors Associated with Job Content Plateauing among Older Workers

    ERIC Educational Resources Information Center

    Armstrong-Stassen, Marjorie

    2008-01-01

    Purpose: The purpose of this paper is to identify personal and work environment factors associated with the experience of job content plateauing among older workers. Design/methodology/approach: Two cross-sectional studies, each including two samples, were conducted. In each study, one sample consisted of a diverse group of older workers and the…

  6. Second Plateau Voltage in Nickel-cadmium Cells

    NASA Technical Reports Server (NTRS)

    Vasanth, K. L.

    1984-01-01

    Sealed nickel cadmium cells having large number of cycles on them are discharged using Hg/HgO reference electrode. The negative electrode exhibits the second plateau. A SEM of negative plates of such cells show a number of large crystals of cadmium hydroxide. The large crystals on the negative plates disappear after continuous overcharging in flooded cells.

  7. Threshold friction velocity of soils within the Columbia Plateau

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind erosion only occurs when the friction velocity exceeds the threshold friction velocity (TFV) of the surface. The TFV of loessial soils commonly found across the Columbia Plateau region of the U.S. Pacific Northwest is virtually unknown even though these soils are highly erodible and a source of...

  8. Newborns' Face Recognition: Role of Inner and Outer Facial Features

    ERIC Educational Resources Information Center

    Turati, Chiara; Macchi Cassia, Viola; Simion, Francesca; Leo, Irene

    2006-01-01

    Existing data indicate that newborns are able to recognize individual faces, but little is known about what perceptual cues drive this ability. The current study showed that either the inner or outer features of the face can act as sufficient cues for newborns' face recognition (Experiment 1), but the outer part of the face enjoys an advantage…

  9. Long-Lived Glass Mirrors For Outer Space

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.; Maag, Carl R.; Heggen, Philip M.

    1988-01-01

    Paper summarizes available knowledge about glass mirrors for use in outer space. Strengths and weaknesses of various types of first and second reflective surfaces identified. Second-surface glass mirrors used in outer space designed to different criteria more stringent for terrestrial mirrors. Protons, electrons, cosmic rays, meteorites, and orbiting space debris affect longevities of components. Contamination also factor in space.

  10. 27 CFR 9.207 - Outer Coastal Plain.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Outer Coastal Plain. 9.207 Section 9.207 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS AMERICAN VITICULTURAL AREAS Approved American Viticultural Areas § 9.207 Outer Coastal Plain. (a) Name. The name of...

  11. Far Outer Galaxy H II Regions

    NASA Technical Reports Server (NTRS)

    Rudolph, A. L.; deGues, E. J.; Brand, J.; Wouterloot, J. G. A.; Gross, Anthony R. (Technical Monitor)

    1994-01-01

    We have made a multifrequency (6, 3.6, and 2 cm), high-resolution (3"-6"), radio continuum survey of IRAS selected sources from the catalogue of Wouterloot & Brand (1989) to search for and study H II regions in the far outer Galaxy. We identified 31 sources in this catalog with well determined galactocentric distances, and with R approx.. greater than 15 kpc and L(sub FIR) approx.greater than 10(exp 4) solar luminosity, indicating the presence of high-mass star-formation. We have observed 11 of these sources with the Very Large Array (VLA). We observed the sources at 6 and 2 cm using "scaled arrays", making possible a direct and reliable comparison of the data at these two wavelengths for the determination of spectral indices. We detected a total of 12 radio sources, of which 10 have spectral indices consistent with optically-thin free-free emission from H II regions. Combined with previous VLA observations by other investigators, we have data on a total of 15 H II regions at galactocentric distances of 15 to 18.2kpc, among the most remote H II regions found in our Galaxy. The sizes of the H II regions range from approx. less than 0.10 to 2.3 pc. Using the measured fluxes and sizes, we determine the electron densities, emission measures, and excitation parameters of the H II regions, as well as the fluxes of Lyman continuum photons needed to keep the nebulae ionized. The sizes and electron densities are consistent with most of the sources detected in this survey being compact or ultracompact H II regions. Seven of the fifteen H II regions have sizes approx. less than 0.20 pc. Assuming simple pressure-driven expansion of the H II regions, these sizes indicate ages approx. less than 5 x 10(exp 4) yr, or only 1% of the lifetime of an O star, which implies an unlikely overabundance of O stars in the outer Galaxy. Thus, the large number of compact H II regions suggests that the time these regions spend in a compact phase must be much longer than their dynamical

  12. Dynamo in the Outer Heliosheath: Necessary Conditions

    NASA Astrophysics Data System (ADS)

    Belenkaya, E. S.

    2015-07-01

    On 25 August 2012 at 121.7 AU, Voyager 1 crossed the heliopause and measured a magnetic field with a strength of 0.4 nT in the very local interstellar medium (VLISM), while in the inner heliosheath it was 0.2 nT. The magnetic-field orientation was close to the spiral, and its direction did not change during the heliopause crossing. Simultaneously with the increase of magnetic-field magnitude at the heliopause, the number of energetic heliospheric particles and the temperature decreased substantially. At the same time, the Galactic cosmic-ray intensity enhanced together with the plasma density (from near the termination shock to beyond the heliopause). If an increase of the density in the VLISM corresponding to a decrease in the temperature was expected, the strange behavior of the magnetic field causes doubt: did the heliopause-crossing take place? Here we suggest a dynamo mechanism as a possible reason for the observed magnetic-field behavior. We enumerate the necessary conditions for the dynamo process and analyze the Voyager 1 observations to test whether these conditions hold or not. We show that all preconditions are realized and estimate the energy of the dynamo action potential. We conclude that in principle, this process could work just beyond the heliopause, because differential rotation may exist in the nearest part of the outer heliosheath, in a layer where electric conductivity is high, but lower than the field-aligned conductivity in the surrounding regions and where the rotational kinetic-energy density is comparable with the observed magnetic-energy density. The latter circumstance corresponds to a requirement of dynamo action, for which kinetic energy of rotation provided by the Sun is an energy source for magnetic amplification.

  13. Cratering Rates in the Outer Solar System

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin

    2003-01-01

    We have constructed a self-consistent study of cratering rates in the outer solar system. Two papers were written, one on cratering asymmetries on synchronously rotating satellites and the other on the cratering rates themselves. The first addresses the well-founded expectation that the leading hemisphere of a synchronously rotating satellite should be more heavily cratered than the trailing hemisphere, and how our solar system has avoided showing much sign of this. We conclude that Ganymede has in the past rotated nonsynchronously, which may imply that it once harboured a thicker inner ocean than it does now. The other study began as an attempt to determine the age of the surface of Europa at a time when Europa was regarded as a major Exobiological target. In keeping with changing times the study expanded to the point that it now recommends cratering rates for worlds as diverse as Charon and Pluto, and includes the contributions of several invaluable co-authors, none of whom would agree with all of my conclusions. The nexus of the work is the size-frequency distribution of comets striking Jupiter (Figure). This was determined using the historically observed record of comets striking or nearly striking Jupiter; the size-frequency distributions of craters on lightly cratered surfaces of Europa, Ganymede, and Triton; and the size-frequncy distribution of Kuiper Belt objects. Extreme reductionists will be happy to know that the surface of Europa probably has an age of around 50 million years. Perhaps more intriguing is that Neptune's moon Triton, by origin a giant comet and by capture and orbital evolution a once fully melted giant comet, has a surface that is probably no older than Europa's.

  14. FBL Outer Can Welder Analysis Software

    SciTech Connect

    Collins, Susan L.

    2003-04-21

    The Outer Can Welder Analysis Software (OCWAS) was originally developed by SRTC for use at Hanford to assist in the storage of their excess plutonium in the DOE standard 3013 containers until it can be properly dispositioned using one of the approved DOE methods. After that development effort, SRS funded SRTC to develop a similar system for FB-Line for use with 3013 canister welding at SRS. More robust analysis routines and techniques were used with this new version as well as enhanced graphical representation of the data. During the welding process, critical weld parameters such as weld current and voltage, can give valuable information about the weld. In the past, weld data from the TIG welding process, has been monitored using strip chart recorders. The data from the weld process, recorded on the strip chart recorder traces, are reviewed to analyze the weld. To improve this process, another software package developed by SRTC, the OCW DAS, digitizes the weld data and stores the data in a file. The OCWAS automates the weld analysis process by analyzing the data obtained during the weld process. The OCWAS reads a data file that was previously collected using the OCW DAS software. The software will read the file and parse the data. The user is first prompted to enter the file name. The file is then opened and the operator name, canister identification, and Date/Time of Acquisition are read from the file and displayed on the screen. The binary weld data is then read from the file into an array until the end of the file is reached. The current, voltage, and position data are displayed on the screen in graphical format on the front panel. The weld power and resistance are calculated and are also displayed in graphical format on the front panel.

  15. Proteomics of Aggregatibacter actinomycetemcomitans Outer Membrane Vesicles.

    PubMed

    Kieselbach, Thomas; Zijnge, Vincent; Granström, Elisabeth; Oscarsson, Jan

    2015-01-01

    Aggregatibacter actinomycetemcomitans is an oral and systemic pathogen associated with aggressive forms of periodontitis and with endocarditis. Outer membrane vesicles (OMVs) released by this species have been demonstrated to deliver effector proteins such as cytolethal distending toxin (CDT) and leukotoxin (LtxA) into human host cells and to act as triggers of innate immunity upon carriage of NOD1- and NOD2-active pathogen-associated molecular patterns (PAMPs). To improve our understanding of the pathogenicity-associated functions that A. actinomycetemcomitans exports via OMVs, we studied the proteome of density gradient-purified OMVs from a rough-colony type clinical isolate, strain 173 (serotype e) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This analysis yielded the identification of 151 proteins, which were found in at least three out of four independent experiments. Data are available via ProteomeXchange with identifier PXD002509. Through this study, we not only confirmed the vesicle-associated release of LtxA, and the presence of proteins, which are known to act as immunoreactive antigens in the human host, but we also identified numerous additional putative virulence-related proteins in the A. actinomycetemcomitans OMV proteome. The known and putative functions of these proteins include immune evasion, drug targeting, and iron/nutrient acquisition. In summary, our findings are consistent with an OMV-associated proteome that exhibits several offensive and defensive functions, and they provide a comprehensive basis to further disclose roles of A. actinomycetemcomitans OMVs in periodontal and systemic disease. PMID:26381655

  16. Motile responses in outer hair cells.

    PubMed

    Zenner, H P

    1986-01-01

    Motile responses of cochlear hair cells open new perspectives for the understanding of cochlear hearing mechanisms and hearing disorders located in hair cells. Direct visualization of hair cell motility was achieved by a method for the study of living isolated mammalian outer hair cells (OHCs) which has overcome some of the complexities in dealing with the heterogeneous organ of Corti. Electrophysiological giga-seal whole-cell recordings of single OHC prepared by this approach had revealed negative cell potentials ranging from -32 mV to -70 mV (Gitter et al. (1986) Oto-Rhino-Laryngol. in press). Elucidation of HC motility has come from two lines of experiments. One follows from the observation that exposure of the lateral and basal membrane parts of living OHCs to increasing bath K+ concentrations resulted in a sustained reversible depolarization of the cell. Here, we report that by depolarization of the cell membrane in the presence of 25-125 mM K+/Cl- a sustained contraction of OHC was induced. This was followed by relaxation in the presence of artificial perilymph containing 5.4 mM K+/Cl-. By alternating these procedures OHCs were made to undergo as many as five cycles of contraction and relaxation. External Ca2+ was not required for the initial contraction but was essential for relaxation. Following repeated contraction/relaxation cycles the cytoplasm of individual OHCs exhibited a filamentous network, correlating with a new infracuticular anti-actin binding capacity. The second series of experiments originates in the observation that permeabilized OHCs contracted in the presence of ATP. No response was seen in the presence of control nucleotides.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3733547

  17. FBL Outer Can Welder Analysis Software

    Energy Science and Technology Software Center (ESTSC)

    2003-04-21

    The Outer Can Welder Analysis Software (OCWAS) was originally developed by SRTC for use at Hanford to assist in the storage of their excess plutonium in the DOE standard 3013 containers until it can be properly dispositioned using one of the approved DOE methods. After that development effort, SRS funded SRTC to develop a similar system for FB-Line for use with 3013 canister welding at SRS. More robust analysis routines and techniques were used withmore » this new version as well as enhanced graphical representation of the data. During the welding process, critical weld parameters such as weld current and voltage, can give valuable information about the weld. In the past, weld data from the TIG welding process, has been monitored using strip chart recorders. The data from the weld process, recorded on the strip chart recorder traces, are reviewed to analyze the weld. To improve this process, another software package developed by SRTC, the OCW DAS, digitizes the weld data and stores the data in a file. The OCWAS automates the weld analysis process by analyzing the data obtained during the weld process. The OCWAS reads a data file that was previously collected using the OCW DAS software. The software will read the file and parse the data. The user is first prompted to enter the file name. The file is then opened and the operator name, canister identification, and Date/Time of Acquisition are read from the file and displayed on the screen. The binary weld data is then read from the file into an array until the end of the file is reached. The current, voltage, and position data are displayed on the screen in graphical format on the front panel. The weld power and resistance are calculated and are also displayed in graphical format on the front panel.« less

  18. Proteomics of Aggregatibacter actinomycetemcomitans Outer Membrane Vesicles

    PubMed Central

    Kieselbach, Thomas; Zijnge, Vincent; Granström, Elisabeth; Oscarsson, Jan

    2015-01-01

    Aggregatibacter actinomycetemcomitans is an oral and systemic pathogen associated with aggressive forms of periodontitis and with endocarditis. Outer membrane vesicles (OMVs) released by this species have been demonstrated to deliver effector proteins such as cytolethal distending toxin (CDT) and leukotoxin (LtxA) into human host cells and to act as triggers of innate immunity upon carriage of NOD1- and NOD2-active pathogen-associated molecular patterns (PAMPs). To improve our understanding of the pathogenicity-associated functions that A. actinomycetemcomitans exports via OMVs, we studied the proteome of density gradient-purified OMVs from a rough-colony type clinical isolate, strain 173 (serotype e) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This analysis yielded the identification of 151 proteins, which were found in at least three out of four independent experiments. Data are available via ProteomeXchange with identifier PXD002509. Through this study, we not only confirmed the vesicle-associated release of LtxA, and the presence of proteins, which are known to act as immunoreactive antigens in the human host, but we also identified numerous additional putative virulence-related proteins in the A. actinomycetemcomitans OMV proteome. The known and putative functions of these proteins include immune evasion, drug targeting, and iron/nutrient acquisition. In summary, our findings are consistent with an OMV-associated proteome that exhibits several offensive and defensive functions, and they provide a comprehensive basis to further disclose roles of A. actinomycetemcomitans OMVs in periodontal and systemic disease. PMID:26381655

  19. Planetesimal Formation in the Outer Solar Nebula

    NASA Technical Reports Server (NTRS)

    Supulver, K. D.

    1996-01-01

    A numerical investigation of the orbital trajectories of individual particles in the turbulent outer solar nebula has been performed. The (spherical) particle consists of an unchanging mm-sized 'dust' core surrounded by an H2O ice mantle; the density of both core and mantle is 0.5 g/cm(exp 3). The simulations include the effects of H2O condensation from the gas phase, H2O sublimation from the particle surface, and collisional growth via particle collisions with a background distribution of small H2O grains. The model nebula is an azimuthally symmetric minimum-mass nebula of solar composition with a vertical (and radial) temperature gradient. Particle evolution follows a pattern. A particle starting out in a cool region grows via condensation and collisional accretion until it is large enough (decimeter- to meter-sized) to decouple somewhat from the turbulence. (This growth occurs on a timescale of several thousand years at 10 AU; at 30 AU, the timescale is approx. 104 years.) The particle then moves rapidly inward toward the sun due to secular gas drag forces, sublimates much of its icy mantle, and slows its inward migration as it gets caught up in the turbulence again (due to its now-smaller size) at the 'sublimation boundary,' where the ambient gas temperature is approx. 150 K. Such a process could, on a short timescale (i.e., a timescale much shorter than the nebular gas lifetime of approx. 106 yr), generate a population of decimeter- to meter-sized bodies which would then collisionally accrete to form planetesimals.

  20. Molecular identity of human outer radial glia during cortical development.

    PubMed

    Pollen, Alex A; Nowakowski, Tomasz J; Chen, Jiadong; Retallack, Hanna; Sandoval-Espinosa, Carmen; Nicholas, Cory R; Shuga, Joe; Liu, Siyuan John; Oldham, Michael C; Diaz, Aaron; Lim, Daniel A; Leyrat, Anne A; West, Jay A; Kriegstein, Arnold R

    2015-09-24

    Radial glia, the neural stem cells of the neocortex, are located in two niches: the ventricular zone and outer subventricular zone. Although outer subventricular zone radial glia may generate the majority of human cortical neurons, their molecular features remain elusive. By analyzing gene expression across single cells, we find that outer radial glia preferentially express genes related to extracellular matrix formation, migration, and stemness, including TNC, PTPRZ1, FAM107A, HOPX, and LIFR. Using dynamic imaging, immunostaining, and clonal analysis, we relate these molecular features to distinctive behaviors of outer radial glia, demonstrate the necessity of STAT3 signaling for their cell cycle progression, and establish their extensive proliferative potential. These results suggest that outer radial glia directly support the subventricular niche through local production of growth factors, potentiation of growth factor signals by extracellular matrix proteins, and activation of self-renewal pathways, thereby enabling the developmental and evolutionary expansion of the human neocortex. PMID:26406371

  1. Characterization of the major outer membrane antigens of Treponema hyodysenteriae.

    PubMed Central

    Wannemuehler, M J; Hubbard, R D; Greer, J M

    1988-01-01

    Outer membrane extracts of Treponema hyodysenteriae were used to evaluate the antibody responses in immunized or convalescent pigs. Western blot (immunoblot) analysis identified antibodies in sera reactive with 14- to 19-kilodalton (kDa) antigens. Reactivity against these antigens could be removed only by absorption of sera with butanol-water-extracted endotoxin from the homologous strain of T. hyodysenteriae. Treatment of the outer membrane extracts with 0.1 M sodium meta-periodate, but not with proteinase K, abolished reactivity with both outer membrane and endotoxin antigens (14 and 19 kDa). These results indicate that swine vaccinated with the outer membrane extract of T. hyodysenteriae develop antibody responses to outer membrane antigens qualitatively similar to those of swine convalescing from active infection, especially antibodies against low-molecular-mass antigens. The nature of the 14- to 19-kDa antigens appears consistent with that of treponemal endotoxin and lipopolysaccharide. Images PMID:2460406

  2. Rapid loss of lakes on the Mongolian Plateau

    PubMed Central

    Tao, Shengli; Fang, Jingyun; Zhao, Xia; Zhao, Shuqing; Shen, Haihua; Hu, Huifeng; Tang, Zhiyao; Wang, Zhiheng; Guo, Qinghua

    2015-01-01

    Lakes are widely distributed on the Mongolian Plateau and, as critical water sources, have sustained Mongolian pastures for hundreds of years. However, the plateau has experienced significant lake shrinkage and grassland degradation during the past several decades. To quantify the changes in all of the lakes on the plateau and the associated driving factors, we performed a satellite-based survey using multitemporal Landsat images from the 1970s to 2000s, combined with ground-based censuses. Our results document a rapid loss of lakes on the plateau in the past decades: the number of lakes with a water surface area >1 km2 decreased from 785 in the late 1980s to 577 in 2010, with a greater rate of decrease (34.0%) in Inner Mongolia of China than in Mongolia (17.6%). This decrease has been particularly pronounced since the late 1990s in Inner Mongolia and the number of lakes >10 km2 has declined by 30.0%. The statistical analyses suggested that in Mongolia precipitation was the dominant driver for the lake changes, and in Inner Mongolia coal mining was most important in its grassland area and irrigation was the leading factor in its cultivated area. The deterioration of lakes is expected to continue in the following decades not only because of changing climate but also increasing exploitation of underground mineral and groundwater resources on the plateau. To protect grasslands and the indigenous nomads, effective action is urgently required to save these valuable lakes from further deterioration. PMID:25646423

  3. Crustal structure of the Columbia Plateau region, Washington

    SciTech Connect

    Rohay, A.C.; Malone, S.D.

    1983-04-01

    Refraction data from blasts recorded in eastern Washington between 1980 and 1983 are used to determine the upper crustal structure of the Columbia Plateau. Fourteen blast sites with over 25 individual shots were recorded on the University of Washington regional seismic network made up of 36 short-period seismograph stations recorded digitally at 100 samples/s. Additional data were obtained from a 12-station dense digital network in the central plateau operated by the Rockwell Hanford Operations Basalt Waste Isolation Project. Major crustal refractors of 5.1 and 6.05 km/s are observed at distances of 15 to 50 km and 50 to 120 km, respectively. A time-term method is used to model layer thicknesses below the stations for each major refractor. A statistical source-receiver separation operation is used to handle the inherent nonindependence of the data. Constraints are used to fix the mean values of the time terms. Ray tracing through two-dimensional velocity structures is used to augment the interpretation of the time-term solutions for areas where the lateral velocity changes are large. Station delays for the 5.1-km/s layer show a good correlation with elevation and surficial geology. The areal extent of the 5.1-km/s layer roughly coincides with the Columbia River basalts. Time terms from the 6.05-km/s layer indicate a nearly uniform depth of 1 to 2 km in the northern plateau. Time terms in the central plateau indicate a depth to the 6.05-km/s layer of over 8 km, and a systematic thinning away from its center. Magnetotelluric studies indicate that the basalts are probably no thicker than 5 km in the central Columbia Plateau region.

  4. Rapid loss of lakes on the Mongolian Plateau.

    PubMed

    Tao, Shengli; Fang, Jingyun; Zhao, Xia; Zhao, Shuqing; Shen, Haihua; Hu, Huifeng; Tang, Zhiyao; Wang, Zhiheng; Guo, Qinghua

    2015-02-17

    Lakes are widely distributed on the Mongolian Plateau and, as critical water sources, have sustained Mongolian pastures for hundreds of years. However, the plateau has experienced significant lake shrinkage and grassland degradation during the past several decades. To quantify the changes in all of the lakes on the plateau and the associated driving factors, we performed a satellite-based survey using multitemporal Landsat images from the 1970s to 2000s, combined with ground-based censuses. Our results document a rapid loss of lakes on the plateau in the past decades: the number of lakes with a water surface area >1 km(2) decreased from 785 in the late 1980s to 577 in 2010, with a greater rate of decrease (34.0%) in Inner Mongolia of China than in Mongolia (17.6%). This decrease has been particularly pronounced since the late 1990s in Inner Mongolia and the number of lakes >10 km(2) has declined by 30.0%. The statistical analyses suggested that in Mongolia precipitation was the dominant driver for the lake changes, and in Inner Mongolia coal mining was most important in its grassland area and irrigation was the leading factor in its cultivated area. The deterioration of lakes is expected to continue in the following decades not only because of changing climate but also increasing exploitation of underground mineral and groundwater resources on the plateau. To protect grasslands and the indigenous nomads, effective action is urgently required to save these valuable lakes from further deterioration. PMID:25646423

  5. Shiga Toxin-Producing Escherichia coli in Plateau Pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China

    PubMed Central

    Bai, Xiangning; Zhang, Wang; Tang, Xinyuan; Xin, Youquan; Xu, Yanmei; Sun, Hui; Luo, Xuelian; Pu, Ji; Xu, Jianguo; Xiong, Yanwen; Lu, Shan

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) are an emerging group of zoonotic pathogens. Ruminants are the natural reservoir of STEC. In this study we determined the prevalence and characteristics of the STEC in plateau pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China. A total of 1116 pika samples, including 294 intestinal contents samples, 317 fecal samples, and 505 intestinal contents samples, were collected from May to August in the years 2012, 2013, and 2015, respectively. Twenty-one samples (1.88%) yielded at least one STEC isolate; in total, 22 STEC isolates were recovered. Thirteen different O serogroups and 14 serotypes were identified. One stx1 subtype (stx1a) and three stx2 subtypes (stx2a, stx2b, and stx2d) were present in the STEC isolates. Fifteen, fourteen, and three STEC isolates harbored the virulence genes ehxA, subA, and astA, respectively. Adherence-associated genes iha and saa were, respectively, present in 72.73 and 68.18% of the STEC isolates. Twenty antibiotics were active against all the STEC isolates; all strains were resistant to penicillin G, and some to cephalothin or streptomycin. The 22 STEC isolates were divided into 16 pulsed-field gel electrophoresis patterns and 12 sequence types. Plateau pikas may play a role in the ongoing circulation of STEC in the Qinghai-Tibetan plateau. This study provides the first report on STEC in plateau pikas and new information about STEC reservoirs in wildlife. Based on the serotypes, virulence gene profiles and multi-locus sequence typing (MLST) analysis, the majority of these pika STECs may pose a low public health risk. PMID:27047483

  6. Into Tibet: An Early Pliocene Dispersal of Fossil Zokor (Rodentia: Spalacidae) from Mongolian Plateau to the Hinterland of Tibetan Plateau.

    PubMed

    Li, Qiang; Wang, Xiaoming

    2015-01-01

    This paper reports the fossil zokors (Myospalacinae) collected from the lower Pliocene (~4.4 Ma) of Zanda Basin, southwestern Tibet, which is the first record in the hinterland of Tibetan Plateau within the Himalayan Range. Materials include 29 isolated molars belonging to Prosiphneus eriksoni (Schlosser, 1924) by having characters including large size, highly fused roots, upper molars of orthomegodont type, m1 anterior cap small and centrally located, and first pair of m1 reentrants on opposing sides, high crowns, and high value of dentine tract parameters. Based on the cladistics analysis, all seven species of Prosiphneus and P. eriksoni of Zanda form a monophyletic clade. P. eriksoni from Zanda, on the other hand, is nearly the terminal taxon of this clade. The appearance of P. eriksoni in Zanda represents a significant dispersal in the early Pliocene from its center of origin in north China and Mongolian Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet. The fast evolving zokors are highly adapted to open terrains at a time when regional climates had become increasingly drier in the desert zones north of Tibetan Plateau during the late Miocene to Pliocene. The occurrence of this zokor in Tibet thus suggests a rather open steppe environment. Based on fossils of large mammals, we have formulated an "out of Tibet" hypothesis that suggests earlier and more primitive large mammals from the Pliocene of Tibet giving rise to the Ice Age megafauna. However, fossil records for large mammals are still too poor to evaluate whether they have evolved from lineages endemic to the Tibetan Plateau or were immigrants from outside. The superior record of small mammals is in a better position to address this question. With relatively dense age intervals and numerous localities in much of northern Asia, fossil zokors provide the first example of an "into Tibet" scenario--earlier and more primitive taxa originated from outside of the Tibetan Plateau and the

  7. Shiga Toxin-Producing Escherichia coli in Plateau Pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China.

    PubMed

    Bai, Xiangning; Zhang, Wang; Tang, Xinyuan; Xin, Youquan; Xu, Yanmei; Sun, Hui; Luo, Xuelian; Pu, Ji; Xu, Jianguo; Xiong, Yanwen; Lu, Shan

    2016-01-01

    Shiga toxin-producing Escherichia coli (STEC) are an emerging group of zoonotic pathogens. Ruminants are the natural reservoir of STEC. In this study we determined the prevalence and characteristics of the STEC in plateau pika (Ochotona curzoniae) on the Qinghai-Tibetan Plateau, China. A total of 1116 pika samples, including 294 intestinal contents samples, 317 fecal samples, and 505 intestinal contents samples, were collected from May to August in the years 2012, 2013, and 2015, respectively. Twenty-one samples (1.88%) yielded at least one STEC isolate; in total, 22 STEC isolates were recovered. Thirteen different O serogroups and 14 serotypes were identified. One stx 1 subtype (stx 1a) and three stx 2 subtypes (stx 2a, stx 2b, and stx 2d) were present in the STEC isolates. Fifteen, fourteen, and three STEC isolates harbored the virulence genes ehxA, subA, and astA, respectively. Adherence-associated genes iha and saa were, respectively, present in 72.73 and 68.18% of the STEC isolates. Twenty antibiotics were active against all the STEC isolates; all strains were resistant to penicillin G, and some to cephalothin or streptomycin. The 22 STEC isolates were divided into 16 pulsed-field gel electrophoresis patterns and 12 sequence types. Plateau pikas may play a role in the ongoing circulation of STEC in the Qinghai-Tibetan plateau. This study provides the first report on STEC in plateau pikas and new information about STEC reservoirs in wildlife. Based on the serotypes, virulence gene profiles and multi-locus sequence typing (MLST) analysis, the majority of these pika STECs may pose a low public health risk. PMID:27047483

  8. Optogenetic Control of Mouse Outer Hair Cells.

    PubMed

    Wu, Tao; Ramamoorthy, Sripriya; Wilson, Teresa; Chen, Fangyi; Porsov, Edward; Subhash, Hrebesh; Foster, Sarah; Zhang, Yuan; Omelchenko, Irina; Bateschell, Michael; Wang, Lingyan; Brigande, John V; Jiang, Zhi-Gen; Mao, Tianyi; Nuttall, Alfred L

    2016-01-19

    Normal hearing in mammals depends on sound amplification by outer hair cells (OHCs) presumably by their somatic motility and force production. However, the role of OHC force production in cochlear amplification and frequency tuning are not yet fully understood. Currently, available OHC manipulation techniques for physiological or clinical studies are limited by their invasive nature, lack of precision, and poor temporal-spatial resolution. To overcome these limitations, we explored an optogenetic approach based on channelrhodopsin 2 (ChR-2), a direct light-activated nonselective cation channel originally discovered in Chlamydomonas reinhardtii. Three approaches were compared: 1) adeno-associated virus-mediated in utero transfer of the ChR-2 gene into the developing murine otocyst, 2) expression of ChR-2(H134R) in an auditory cell line (HEI-OC1), and 3) expression of ChR-2 in the OHCs of a mouse line carrying a ChR-2 conditional allele. Whole cell recording showed that blue light (470 nm) elicited the typical nonselective cation current of ChR-2 with reversal potential around zero in both mouse OHCs and HEI-OC1 cells and generated depolarization in both cell types. In addition, pulsed light stimulation (10 Hz) elicited a 1:1 repetitive depolarization and ChR-2 currents in mouse OHCs and HEI-OC1 cells, respectively. The time constant of depolarization in OHCs, 1.45 ms, is 10 times faster than HEI-OC1 cells, which allowed light stimulation up to rates of 10/s to elicit corresponding membrane potential changes. Our study demonstrates that ChR-2 can successfully be expressed in mouse OHCs and HEI-OC1 cells and that these present a typical light-sensitive current and depolarization. However, the amount of ChR-2 current induced in our in vivo experiments was insufficient to result in measurable cochlear effects. PMID:26789771

  9. Outer Rise Faulting And Mantle Serpentinization

    NASA Astrophysics Data System (ADS)

    Ranero, C. R.; Phipps Morgan, J.; McIntosh, K.; Reichert, C.

    Dehydration of serpentinized mantle of the downgoing slab has been proposed to cause both intermediate depth earthquakes (50-300 km) and arc volcanism at sub- duction zones. It has been suggested that most of this serpentinization occurs beneath the outer rise; where normal faulting earthquakes due to bending cut > 20 km deep into the lithosphere, allowing seawater to reach and react with underlying mantle. However, little is known about flexural faulting at convergent margins; about how many normal faults cut across the crust and how deeply they penetrate into the man- tle; about the true potential of faults as conduits for fluid flow and how much water can be added through this process. We present evidence that pervasive flexural faulting may cut deep into the mantle and that the amount of faulting vary dramatically along strike at subduction zones. Flexural faulting increases towards the trench axis indicat- ing that active extension occurs in a broad area. Multibeam bathymetry of the Pacific margin of Costa Rica and Nicaragua shows a remarkable variation in the amount of flexural faulting along the incoming ocean plate. Several parameters seem to control lateral variability. Off south Costa Rica thick crust of the Cocos Ridge flexes little, and little to no faulting develops near the trench. Off central Costa Rica, normal thick- ness crust with magnetic anomalies striking oblique to the trench displays small offset faults (~200 m) striking similar to the original seafloor fabric. Off northern Costa Rica, magnetic anomalies strike perpendicular to the trench axis, and a few ~100m-offset faults develop parallel to the trench. Further north, across the Nicaraguan margin, magnetic anomalies strike parallel to the trench and the most widespread faulting de- velops entering the trench. Multichannel seismic reflection images in this area show a pervasive set of trenchward dipping reflections that cross the ~6 km thick crust and extend into the mantle to depths of at

  10. Polar Phenomena in Outer Planet Atmospheres

    NASA Astrophysics Data System (ADS)

    Orton, G.; Fletcher, L.; Yanamandra-Fisher, P.; Leyrat, C.; Greathouse, T.; Parrish, P.; Encrenaz, T.; Simon-Miller, A.

    2008-12-01

    Infrared observations of the polar regions of the outer planets have revealed similarities to the Earth's atmosphere and some new phenomena. The most dominant force which is apparent in time-dependent studies of the poles is seasonal radiative forcing, which was detected in Saturn's stratosphere as early as 1973. For Saturn, Uranus and Neptune, planets with substantial obliquities, the seasonally dependent changes are predictable and can be used to constrain abundances of optically active gases and the rate of restoration by stratospheric circulation. In the case of Neptune, recent evidence shows that the heating is sufficient to allow a "leak" from the reservoir of methane in the deep atmosphere into the polar stratosphere. New thermal images of Uranus show that the winter pole of Uranus which has only recently emerged fully from darkness is colder than when it was in the middle of winter when Voyager 2 visited, confirming the substantial seasonal phase delay associated with radiative heating and cooling models. Even Jupiter with its 3-degree obliquity shows clear evidence for seasonal forcing of temperatures in the upper troposphere and stratosphere. The second most prominent characteristic of the resolvable polar temperature fields in Jupiter and Saturn is the formation of polar vortices. Jupiter's polar vortices are cold, similar to those detected in the terrestrial planets; they have sharp equatorward boundaries which are characterized by Rossby waves which rotate at the speed of the local zonal wind flow and are coincident with the similarly irregular boundaries of a polar haze, also known as "polar hoods". The cold vortex at Saturn's northern winter pole is muted, but Saturn also has a unique "warm polar vortex" in the south (late summer) pole which shows no apparent wave structure. Saturn's warm polar vortex has no counterpart in the Earth's atmosphere, where summer radiative warming simply dissipates the cold winter vortex. Saturn also possesses

  11. Purified outer membranes of Serpulina hyodysenteriae contain cholesterol.

    PubMed Central

    Plaza, H; Whelchel, T R; Garczynski, S F; Howerth, E W; Gherardini, F C

    1997-01-01

    We have isolated outer and inner membranes of Serpulina hyodysenteriae by using discontinuous sucrose density gradients. The outer and inner membrane fractions contained less than 1 and 2%, respectively, of the total NADH oxidase activity (soluble marker) in the cell lysate. Various membrane markers including lipooligosaccharide (LOS), the 16-kDa outer membrane lipoprotein (SmpA), and the C subunit of the F1F0 ATPase indicated that the lowest-density membrane fraction contained outer membranes while the high-density membrane fraction contained inner membranes and that both are essentially free of contamination by the periplasmic flagella, a major contaminant of membranes isolated by other techniques. The outer membrane fractions (rho = 1.10 g/cm3) contained 0.25 mg of protein/mg (dry weight), while the inner membrane samples (rho = 1.16 g/cm3) contained significantly more protein (0.55 mg of protein/mg [dry weight]). Lipid analysis revealed that the purified outer membranes contained cholesterol as a major component of the membrane lipids. Treatment of intact S. hyodysenteriae with different concentrations of digitonin, a steroid glycoside that interacts with cholesterol, indicated that the outer membrane could be selectively removed at concentrations as low as 0.125%. PMID:9286995

  12. On the cenozoic uplift and tectonic stability of the Colorado Plateau

    NASA Technical Reports Server (NTRS)

    Morgan, P.; Swanberg, C. A.

    1985-01-01

    Models of plateau uplift which can be applied to the Colorado Plateau are presented. The sequence and consequences of the 2-km Cenzoic uplift of the Plateau and volcanism and rifting in the adjoining Basin and Range and Southern Rocky Mountain-Rio Grande rift provinces are examined. Geologic and geophysical data suggest that more than one mechanism is required to explain the 2 km of uplift, and that thermal expansion and magmatic crustal thickening are the dominant mechanisms. It is argued that the early Cenzoic stability of the Plateau was related to the relatively cool geotherm and hence high strength of the Plateau lithosphere relative to the adjoining regions. As the Plateau lithosphere has been heated and uplift has occurred, the overall stability of the Plateau has decreased.

  13. High pre-industrial and modern Tibetan Plateau fire activity

    NASA Astrophysics Data System (ADS)

    Kehrwald, N. M.; Li, Q.; Wang, N.; Zennaro, P.; Zangrando, R.; Barbante, C.

    2013-12-01

    The South Asian brown cloud created from a mix of biomass burning and fossil fuel aerosols is warming the atmosphere between 5000 to 7000 meters above sea level (m asl) along the southern slope of the Himalaya. The extent to which this atmospheric brown cloud is transported up and over the 7000 to 8000 m asl ridge of the Himalaya and northward across the Tibetan Plateau is unknown. Intense Eastern Asian industry and associated coal burning may also export fossil fuel burning products to the Tibetan Plateau. In addition, local cooking, agricultural and natural fires emit combustion products that alter atmospheric chemistry and are deposited on glacier surfaces. It is essential to differentiate between the effects of fossil fuel and biomass burning across the Tibetan Plateau to determine if combustion products affect glacier surfaces and, by extension, glacier volume. The specific biomarker levoglucosan can only be produced by biomass burning at temperatures of 300°C or higher and is trapped and preserved in glaciers across the globe. This specificity may allow the possibility of differentiating between fossil fuel and biomass burning contributions when comparing levoglucosan concentrations with more general ice core combustion proxies such as black carbon. Here, we present a biomass burning record from the entire 164 m Muztag ice core (36.35°N; 87.17°E; 5780 m asl) and from a southwest to northeast transect of snow pits across the Tibetan Plateau. Multiple total organic carbon and dissolved organic carbon surface samples demonstrate organic carbon concentrations at or near detection limits. However, these samples have high levoglucosan concentrations suggesting that the biomass burning recorded in these sites may be from a regional rather than local source. The Tibetan Plateau levoglucosan concentrations are surprisingly substantially greater than Kilimanjaro levoglucosan concentrations, where Kilimanjaro is located in a relatively similar low-latitude high

  14. Anorogenic plateau formation induced by a heated lithosphere

    NASA Astrophysics Data System (ADS)

    Duesterhoeft, Erik; Oberhänsli, Roland; Wichura, Henry; Bousquet, Romain

    2013-04-01

    Plateau formation processes in geodynamic settings outside of orogens have not been unambiguously established. Those anorogenic plateaus are topographic barriers that reach medium elevations of approximately 1500 m, e.g. South African-, East African- or Mongolian Plateau. They are inferred to be closely link to mantle plumes away from plate boundaries. Such a heat source at the lithosphere-asthenosphere boundary (LAB) have an influence to the density structure of the crust and lithosphere, due to thermal expansion and mineralogical changes. Consequently, these density variations affect topography and thus we hypothesize topographic variations by lithospheric thermal expansion, due to heating processes at the LAB. Based on this hypothesis, we calculated the density distribution along a one-dimensional depth-profile using two different approaches - with and without mineral reactions. Therefore, we present a new petrologic aspect for plateau uplift, because models on plateau uplift generally do not take into account the effects of metamorphic phase transitions and ignore the fact that chemical reactions influence both, the stability of mineral assemblages and rock density. Our model underscores how metamorphic density of the lithosphere varies with depth and reveals how combination of chemical composition of rocks, mineralogy, and geothermal gradient all have significant effects on the density distribution within the lithosphere and ultimately the evolution of anorogenic plateaus. Furthermore, in order to better understand the temporal characteristics of mantle plume related topography we calculated the timing to generate significant topographic uplift. Our results suggest uplift rates of >20 m/Myr within the first 20 Myr after the onset of heating and considerable primary thermal uplift of approximately 700 m after 20 Myr as a viable mechanism for anorogenic plateau formation. In this way, our model may help to explain pre-rift topography of the East-African Plateau

  15. Structural Aspects of Bacterial Outer Membrane Protein Assembly.

    PubMed

    Calmettes, Charles; Judd, Andrew; Moraes, Trevor F

    2015-01-01

    The outer membrane of Gram-negative bacteria is predominantly populated by β-Barrel proteins and lipid anchored proteins that serve a variety of biological functions. The proper folding and assembly of these proteins is essential for bacterial viability and often plays a critical role in virulence and pathogenesis. The β-barrel assembly machinery (Bam) complex is responsible for the proper assembly of β-barrels into the outer membrane of Gram-negative bacteria, whereas the localization of lipoproteins (Lol) system is required for proper targeting of lipoproteins to the outer membrane. PMID:26621472

  16. Self-sterilization of bodies during outer planet entry

    NASA Technical Reports Server (NTRS)

    Hoffman, A. R.; Jaworski, W.; Taylor, D. M.

    1974-01-01

    A body encountering the atmosphere of an outer planet is subjected to heat loads which could result in high temperature conditions that render terrestrial organisms on or within the body nonviable. To determine whether an irregularly shaped entering body, consisting of several different materials, would be sterilized during inadvertent entry at high velocity, the thermal response of a typical outer planet spacecraft instrument was studied. The results indicate that the Teflon insulated cable and electronic circuit boards may not experience sterilizing temperatures during a Jupiter, Saturn, or Titan entry. Another conclusion of the study is that small plastic particles entering Saturn from outer space have wider survival corridors than do those at Jupiter.

  17. Outer packet sets and feature prediction of computer virus

    NASA Astrophysics Data System (ADS)

    Zhang, Ling

    2014-10-01

    The packet sets model was proposed by Prof. Shi in 2008. A packet sets is a set pair composed of internal and outer packet sets, and it has dynamic characteristic. Using packet sets theory, this paper gives the feature prediction of computer virus based on outer packet sets. The concept of virus screening-filtering is given, furthermore, the virus screening-filtering order theorem, composite virus screening-filtering theorem and virus screening-filtering rule are presented. A prediction method of computer virus feature is given based on the results. The outer packet sets is a new tool in the research of the prediction of dynamic virus feature.

  18. Radioisotope Reduction Using Solar Power for Outer Planetary Missions

    NASA Technical Reports Server (NTRS)

    Fincannon, James

    2008-01-01

    Radioisotope power systems have historically been (and still are) the power system of choice from a mass and size perspective for outer planetary missions. High demand for and limited availability of radioisotope fuel has made it necessary to investigate alternatives to this option. Low mass, high efficiency solar power systems have the potential for use at low outer planetary temperatures and illumination levels. This paper documents the impacts of using solar power systems instead of radioisotope power for all or part of the power needs of outer planetary spacecraft and illustrates the potential fuel savings of such an approach.

  19. Bax inserts into the mitochondrial outer membrane by different mechanisms.

    PubMed

    Cartron, Pierre-François; Bellot, Grégory; Oliver, Lisa; Grandier-Vazeille, Xavier; Manon, Stephen; Vallette, François M

    2008-09-01

    Bax insertion into the mitochondrial outer membrane is essential for the implementation of apoptosis. However, little is known about the first stage of Bax integration into the mitochondrial outer membrane. We have recently shown that TOM22, a mitochondrial outer membrane receptor, is important for insertion, although other reports have suggested that only mitochondrial lipids are involved in this process. Here, we show that monomers, but not dimers, of Bax require the presence of TOM22 and TOM40 to integrate into mitochondria. In addition we show that once inserted into the membrane, Bax can act as a receptor for cytosolic Bax. PMID:18687331

  20. SNAREs Interact with Retinal Degeneration Slow and Rod Outer Segment Membrane Protein-1 during Conventional and Unconventional Outer Segment Targeting

    PubMed Central

    Zulliger, Rahel; Conley, Shannon M.; Mwoyosvi, Maggie L.; Stuck, Michael W.; Azadi, Seifollah; Naash, Muna I.

    2015-01-01

    Mutations in the photoreceptor protein peripherin-2 (also known as RDS) cause severe retinal degeneration. RDS and its homolog ROM-1 (rod outer segment protein 1) are synthesized in the inner segment and then trafficked into the outer segment where they function in tetramers and covalently linked larger complexes. Our goal is to identify binding partners of RDS and ROM-1 that may be involved in their biosynthetic pathway or in their function in the photoreceptor outer segment (OS). Here we utilize several methods including mass spectrometry after affinity purification, in vitro co-expression followed by pull-down, in vivo pull-down from mouse retinas, and proximity ligation assay to identify and confirm the SNARE proteins Syntaxin 3B and SNAP-25 as novel binding partners of RDS and ROM-1. We show that both covalently linked and non-covalently linked RDS complexes interact with Syntaxin 3B. RDS in the mouse is trafficked from the inner segment to the outer segment by both conventional (i.e., Golgi dependent) and unconventional secretory pathways, and RDS from both pathways interacts with Syntaxin3B. Syntaxin 3B and SNAP-25 are enriched in the inner segment (compared to the outer segment) suggesting that the interaction with RDS/ROM-1 occurs in the inner segment. Syntaxin 3B and SNAP-25 are involved in mediating fusion of vesicles carrying other outer segment proteins during outer segment targeting, so could be involved in the trafficking of RDS/ROM-1. PMID:26406599

  1. Anatomic femorotibial changes associated with tibial plateau leveling osteotomy

    PubMed Central

    Schultz, Jennifer A.; Allen, David A.; Bergman, Philip J.

    2015-01-01

    This prospective study evaluated anatomic femorotibial changes utilizing the relationship between the intercondylar notch and the intercondylar eminence following tibial plateau leveling osteotomy (TPLO). We hypothesized that TPLO results in anatomic alteration of the femorotibial joint. Pre- and post-operative computed tomography (CT) scans of cranial cruciate deficient stifle joints treated with TPLO were performed on 25 client-owned dogs. Computed tomography scans were performed at 3 different stifle angles: extension, 135° walking angle, and 90° of flexion. Tibial plateau leveling osteotomy did not result in a significant medial or lateral shift of the intercondylar eminence relative to the intercondylar notch. There was a significant cranial shift of the intercondylar eminence with the stifle in extension following TPLO. In addition, TPLO resulted in a significantly narrowed femorotibial joint space. The biomechanical effects of TPLO and medial meniscal release need to be further defined. PMID:26345618

  2. Exploring Aristarchus Plateau as a Potential Lunar Base Site

    NASA Technical Reports Server (NTRS)

    Coombs, Cassandra R.; Hawke, B. Ray; Allen, Carlton C.

    1998-01-01

    As part the exploration strategy, NASA has been studying the feasibility of a low cost human return to the Moon. The currently planned mission has a dual focus on the advancement of lunar science and the use of in situ resources. Thus far, our space exploration plans have relied almost exclusively on equipment and supplies transported from Earth. This may be appropriate for operations in Earth orbit, or for short duration stays on the lunar surface. However, the ability to "live off the land," will prove vital for long term habitation of the Moon and planets. This study takes a close look at the Aristarchus Plateau, one of the primary candidate sites for human lunar exploration. Based on this synthesis study, we recommend two sites on the Aristarchus Plateau that will maximize science return and provide a convincing demonstration of the use of in situ resources and which may be a viable future lunar base site.

  3. Carbon sequestration in two alpine soils on the Tibetan Plateau.

    PubMed

    Tian, Yu-Qiang; Xu, Xing-Liang; Song, Ming-Hua; Zhou, Cai-Ping; Gao, Qiong; Ouyang, Hua

    2009-09-01

    Soil carbon sequestration was estimated in a conifer forest and an alpine meadow on the Tibetan Plateau using a carbon-14 radioactive label provided by thermonuclear weapon tests (known as bomb-(14)C). Soil organic matter was physically separated into light and heavy fractions. The concentration spike of bomb-(14)C occurred at a soil depth of 4 cm in both the forest soil and the alpine meadow soil. Based on the depth of the bomb-(14)C spike, the carbon sequestration rate was determined to be 38.5 g C/m(2) per year for the forest soil and 27.1 g C/m(2) per year for the alpine meadow soil. Considering that more than 60% of soil organic carbon (SOC) is stored in the heavy fraction and the large area of alpine forests and meadows on the Tibetan Plateau, these alpine ecosystems might partially contribute to "the missing carbon sink". PMID:19723249

  4. Independently dated paleomagnetic secular variation records from the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Haberzettl, T.; Henkel, K.; Kasper, T.; Ahlborn, M.; Su, Y.; Appel, E.; St-Onge, G.; Stoner, J. S.; Daut, G.; Wang, J.; Zhu, L.; Maeusbacher, R.

    2014-12-01

    Magnetostratigraphy has been serving as a valuable tool for dating and confirming chronologies of lacustrine sediments in many parts of the world. However, suitable paleomagnetic records on the Tibetan Plateau (TP) and adjacent areas are extremely scarce. Here, independently radiocarbon dated sediments of two lakes on the southern central TP, Tangra Yumco and Taro Co some 250 km further west, were investigated for their potential to record paleomagnetic secular variations. Multiple sediment cores resemble a very similar inclination pattern for the past 4000 years. This demonstrates the high potential of inclination to compare records over the Tibetan Plateau and eventually date other Tibetan records stratigraphically. Comparisons to an existing record from Nam Co, a lake 350 km west of Tangra Yumco, a varve dated record from the Makran Accretionary Wedge, and a stack record from East Asia reveal many similarities. However, model output data of geomagnetic field models for the coordinates of Tangra Yumco do not agree with our findings.

  5. The Manihiki Plateau - a key to missing hotspot tracks?

    NASA Astrophysics Data System (ADS)

    Pietsch, R.; Uenzelmann-Neben, G.

    2016-04-01

    A Neogene magmatic reactivation of the Manihiki Plateau, a Large Igneous Province (LIP) in the central Pacific, is studied using seismic reflection data. Igneous diapirs have been identified exclusively within a narrow WNW-ESE striking corridor in the southern High Plateau (HP), which is parallel to the Neogene Pacific Plate motion and overlaps with an extrapolation of the Society Islands Hotspot path. The igneous diapirs are characterized by a narrow width (>5 km), penetration of the Neogene sediments, and they become progressively younger towards the East (23-10 Ma). The magmatic source appears to be of small lateral extent, which leads to the conclusion that the diapirs represent Neogene hotspot volcanism within a LIP, and thus may be an older, previously unknown extension of the Society Islands Hotspot track (>4.5 Ma). Comparing hotspot volcanism within oceanic and continental lithosphere, we further conclude that hotspot volcanism within LIP crust has similarities to tectonically faulted continental crust.

  6. Tectonic analysis of folds in the Colorado plateau of Arizona

    NASA Technical Reports Server (NTRS)

    Davis, G. H.

    1975-01-01

    Structural mapping and analysis of folds in Phanerozoic rocks in northern Arizona, using LANDSAT-1 imagery, yielded information for a tectonic model useful in identifying regional fracture zones within the Colorado Plateau tectonic province. Since the monoclines within the province developed as a response to differential movements of basement blocks along high-angle faults, the monoclinal fold pattern records the position and trend of many elements of the regional fracture system. The Plateau is divided into a mosaic of complex, polyhedral crustal blocks whose steeply dipping faces correspond to major fracture zones. Zones of convergence and changes in the trend of the monoclinal traces reveal the corners of the blocks. Igneous (and salt) diapirs have been emplaced into many of the designated zones of crustal weakness. As loci of major fracturing, folding, and probably facies changes, the fractures exert control on the entrapment of oil and gas.

  7. Mantle structure beneath the western edge of the Colorado Plateau

    USGS Publications Warehouse

    Sine, C.R.; Wilson, D.; Gao, W.; Grand, S.P.; Aster, R.; Ni, J.; Baldridge, W.S.

    2008-01-01

    Teleseismic traveltime data are inverted for mantle Vp and Vs variations beneath a 1400 km long line of broadband seismometers extending from eastern New Mexico to western Utah. The model spans 600 km beneath the moho with resolution of ???50 km. Inversions show a sharp, large-magnitude velocity contrast across the Colorado Plateau-Great Basin transition extending ???200 km below the crust. Also imaged is a fast anomaly 300 to 600 km beneath the NW portion of the array. Very slow velocities beneath the Great Basin imply partial melting and/or anomalously wet mantle. We propose that the sharp contrast in mantle velocities across the western edge of the Plateau corresponds to differential lithospheric modification, during and following Farallon subduction, across a boundary defining the western extent of unmodified Proterozoic mantle lithosphere. The deep fast anomaly corresponds to thickened Farallon plate or detached continental lithosphere at transition zone depths. Copyright 2008 by the American Geophysical Union.

  8. Anatomic femorotibial changes associated with tibial plateau leveling osteotomy.

    PubMed

    Schultz, Jennifer A; Allen, David A; Bergman, Philip J

    2015-09-01

    This prospective study evaluated anatomic femorotibial changes utilizing the relationship between the intercondylar notch and the intercondylar eminence following tibial plateau leveling osteotomy (TPLO). We hypothesized that TPLO results in anatomic alteration of the femorotibial joint. Pre- and post-operative computed tomography (CT) scans of cranial cruciate deficient stifle joints treated with TPLO were performed on 25 client-owned dogs. Computed tomography scans were performed at 3 different stifle angles: extension, 135° walking angle, and 90° of flexion. Tibial plateau leveling osteotomy did not result in a significant medial or lateral shift of the intercondylar eminence relative to the intercondylar notch. There was a significant cranial shift of the intercondylar eminence with the stifle in extension following TPLO. In addition, TPLO resulted in a significantly narrowed femorotibial joint space. The biomechanical effects of TPLO and medial meniscal release need to be further defined. PMID:26345618

  9. Arthroscopic management of tibial plateau fractures: special techniques.

    PubMed

    Perez Carro, L

    1997-04-01

    Arthroscopic assessment and treatment of tibial plateau fractures has gained popularity in recent years. This article describes some maneuvers to facilitate the management of these fractures with the arthroscope. We use a 14-mm rounded curved periosteal elevator to manipulate fragments within the joint instead of using a probe. To facilitate visualization of fractures, we describe the use of loop sutures around the meniscus to retract the meniscus when there is a tear in the meniscus. We suggest the use of the arthroscope for directly viewing the interosseous space to be sure that any internal fixation devices remain outside the articular space. The use of these tactics will allow a faster, more accurate reduction with less radiation exposure in patients with displaced tibial plateau fractures. PMID:9127091

  10. [Dynamic changes of Ruoergai Plateau wetland ecosystem service value].

    PubMed

    Zhang, Xiao-Yun; Lü, Xian-Guo; Shen, Song-Ping

    2009-05-01

    Based on the satellite remote sensing data acquired in 1975 and 2006, and by using the assessment method of ecosystem service value, the dynamic changes of physical production value, gas regulation value, and water storage value of Ruoergai Plateau wetland ecosystem in 1975-2006 were studied. During study period, the total value of the three services decreased from 19.59 billion RMB Yuan to 12.38 billion Yuan RMB, among which, physical production value increased by 0.302 billion RMB Yuan, while the gas regulation and water storage value decreased by 7.507 billion RMB Yuan. The benefit from the increase of physical production was much less than the loss of ecosystem degradation. Overgrazing induced the biomass reduction and soil deterioration, resulting in the decline of Ruoergai Plateau wetland ecosystem service value and service capacity. PMID:19803173

  11. [Minimally invasive treatment of tibial plateau fracture under arthroscopy monitoring].

    PubMed

    Chen, Lixin; Ma, Shaoyun; Li, Xianpeng

    2014-05-01

    Twenty six patients with fracture of tibial plateau was under arthroscopy assisted reduction, the joint surface of bone graft, and USES the steel plate fixation treatment. Average surgery time was 65 min (70-120 min), average fracture healing time was 15 weeks (12-17 weeks), joint surface anatomical reattachment rate was 92.9%. Using break knee function criteria evaluation of curative effect: 18 cases great 6 cases wed, 2 cases ok, fine rate was 92.3%. No infection, deep venous thrombosis and small leg fascia chamber syndrome and other complications. Conclusion is that treatment of tibial plateau fractures under arthroscope has advantages of small trauma, check intuitively and reset accurately, functional recovery of patients are satisfied, the treatment has certain clinical application value. PMID:25241526

  12. Comparative Proteome Analysis of Spontaneous Outer Membrane Vesicles and Purified Outer Membranes of Neisseria meningitidis

    PubMed Central

    Otto, Andreas; Becher, Dörte; Vogel, Ulrich

    2013-01-01

    Outer membrane vesicles (OMVs) of Gram-negative bacteria receive increasing attention because of various biological functions and their use as vaccines. However, the mechanisms of OMV release and selective sorting of proteins into OMVs remain unclear. Comprehensive quantitative proteome comparisons between spontaneous OMVs (SOMVs) and the outer membrane (OM) have not been conducted so far. Here, we established a protocol for metabolic labeling of neisserial proteins with 15N. SOMV and OM proteins labeled with 15N were used as an internal standard for proteomic comparison of the SOMVs and OMs of two different strains. This labeling approach, coupled with high-sensitivity mass spectrometry, allowed us to comprehensively unravel the proteome of the SOMVs and OMs. We quantified the relative distribution of 155 proteins between SOMVs and the OM. Complement regulatory proteins, autotransporters, proteins involved in iron and zinc acquisition, and a two-partner secretion system were enriched in SOMVs. The highly abundant porins PorA and PorB and proteins connecting the OM with peptidoglycan or the inner membrane, such as RmpM, MtrE, and PilQ, were depleted in SOMVs. Furthermore, the three lytic transglycosylases MltA, MltB, and Slt were less abundant in SOMVs. In conclusion, SOMVs are likely to be released from surface areas with a low local abundance of membrane-anchoring proteins and lytic transglycosylases. The enrichment of complement regulatory proteins, autotransporters, and trace metal binding and transport proteins needs to be explored in the context of the pathogenesis of meningococcal disease. PMID:23893116

  13. Cartilage fibrillation on the lateral tibial plateau in Liverpool necropsies.

    PubMed Central

    Meachim, G

    1976-01-01

    A study has been made of the state at necropsy of the hyaline articular cartilage of the left tibial plateaux, with particular reference to the lateral plateau, in 47 adult white Europeans (24 men; 23 women) aged 21-88 years. The surface morphology and topographical distribution of the lesions is described for the bare area of the lateral plateau and its meniscus-covered segments, and quantitative point-counting data are presented for the amount, according to age, of overt fibrillation on the bare area. A variety of cartilage lesions was encountered: macroscopically apparent ' parallel linear' minimal fibrillation; other patterns of minimal fibrillation; 'ravines'; overt fibrillation; localized incomplete defects of the cartilage; and full-thickness cartilage loss with bone exposure. Sites of superficial fraying and splitting of the hyaline articular cartilage are a normal finding on adult human tibial plateaux. Especially in younger adults, such sites are often accompanied by large areas of cartilage surface which are still intact. On the lateral plateau, the bare area and the meniscus-covered posterior segment are more susceptible to overt fibrillation than are the meniscus-covered lateral and anterior segments. In contrast to the findings in other synovial joints, the peripheral rim of the upper tibial cartilage sheet is not particularly susceptible to overt fibrillation. Tangential extension of the changes on the lateral plateau leads to widespread involvement of the bare area and the meniscus-covered posterior segment in older subjects. However, vertical progression of the changes, sufficient to give full-thickness cartilage loss with tibio-femoral bone exposure, was seen in only a minority of persons aged over 80 years. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 10 Fig. 11 Fig. 12 PMID:946428

  14. Climate, Permafrost, and Landscape Interactions on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Zhang, T.; Frauenfeld, O. W.; Wu, Q.; Ma, L.

    2008-12-01

    Observational evidence indicates that climate warming has been well underway on the Qinghai-Tibetan Plateau (QTP) for the past few decades, manifest through increases in station air temperature across the Plateau. Given the high elevation and extremely complex terrain of the QTP, an important consideration in evaluating in situ station observations for climate change is the fact that observing sites are almost always located in convenient, easily accessible places. On the QTP, this often translates to non-representative low- lying valley areas near population centers. ERA-40 reanalysis air temperatures, from an atmospheric model, provide an alternative measure of surface air temperatures, free of such biases. ERA-40 is in very good agreement in terms of interannual variability with in situ measurements. However, there are significant differences in the absolute magnitude of temperatures, as well as the long-term trends. An unresolved question is the degree to which the observed warming on the QTP is caused by anthropogenic effects over the past several decades, and the contribution of data quality issues. Our preliminary findings suggest that the observed climate warming on the Plateau may in part be due to local land cover and land use change. Using available ground-based measurements, ERA-40 reanalysis data, and satellite remote sensing data, we provide an assessment of the relative roles of air temperature, precipitation, and vegetation change on QTP and their roles in climate warming. An important additional factor in this semi-arid environment is the presence of permafrost. Plateau-wide permafrost degradation will intensify melting of ground ice, development of thermokarst, thaw lake drainage, and slope instability. These surface geomorphologic processes also have a significant impact on vegetation and ecosystem dynamics and, ultimately, on the climate system. We thus also assess the response of permafrost to climate warming and increased human activity, and

  15. The Colorado Plateau: cultural, biological, and physical research

    USGS Publications Warehouse

    Cole, Kenneth L.

    2004-01-01

    Stretching from the four corners of Arizona, New Mexico, Colorado, and Utah, the Colorado Plateau is a natural laboratory for a wide range of studies. This volume presents 23 original articles drawn from more than 100 research projects presented at the Sixth Biennial Conference of Research on the Colorado Plateau. This scientific gathering revolved around research, inventory, and monitoring of lands in the region. The book's contents cover management techniques for cultural, biological, and physical resources, representing collaborative efforts among federal, university, and private sector scientists and land managers. Chapters on cultural concerns cover benchmarks of modern southwestern anthropological knowledge, models of past human activity and impact of modern visitation at newly established national monuments, challenges in implementing the 1964 Wilderness Act, and opportunities for increased federal research on Native American lands. The section on biological resources comprises sixteen chapters, with coverage that ranges from mammalian biogeography to responses of elk at the urban-wildland interface. Additional biological studies include the effects of fire and grazing on vegetation; research on bald eagles at Grand Canyon and tracking wild turkeys using radio collars; and management of palentological resources. Two final chapters on physical resources consider a proposed rerouting of the Rio de Flag River in urban Flagstaff, Arizona, and an examination of past climate patterns over the Plateau, using stream flow records and tree ring data. In light of similarities in habitat and climate across the Colorado Plateau, techniques useful to particular management units have been found to be applicable in many locations. This volume highlights an abundance of research that will prove useful for all of those working in the region, as well as for others seeking comparative studies that integrate research into land management actions.

  16. The Shillong Plateau and the great 1897 Assam earthquake

    NASA Astrophysics Data System (ADS)

    England, Philip; Bilham, Roger

    2015-09-01

    Previous analysis of triangulation data of the Survey of India concluded that the great 1897 Assam earthquake occurred on a south dipping fault near the northern edge of the Shillong Plateau, which was named the Oldham fault. This attribution has been questioned on geological and geodetic grounds. We refine the triangulation data, adding recently discovered observations, and demonstrate that they require average slip of 25 ± 5 m on a fault that dips south at ˜40° beneath the plateau. The best fitting solution to the geodetic observations gives a rupture length of 79 km. However, the Chedrang fault, immediately to the west of the Oldham fault, appears to have slipped as a subvertical tear fault during or shortly after the 1897 earthquake, with over 10 m of down-to-the-west normal-sense slip. This observation suggests that the western end of the main rupture approached within a few kilometers of the Chedrang fault, giving a length of 95 km for the rupture. This range of parameters gives a magnitude 8.15Plateau nor by slip on a south dipping fault that has been postulated in the Brahmaputra Valley. GPS velocities show that up to 5 mm/yr of shortening is taken up across the plateau and its borders; this suggests, via moment-frequency relations, that the interval between great earthquakes in the region is several thousand years but that earthquakes of magnitude 7 or greater should occur roughly once per century.

  17. Outer Continental Shelf Oil and Gas Leasing/Production Program

    SciTech Connect

    Not Available

    1988-01-01

    This annual report on the Outer Continental Shelf (OCS) Oil and Gas Leasing and Production program summarizes receipts and expenditures, and includes information on OCS safety violations as reported by the US Coast Guard. 3 figs., 12 tabs.

  18. Nuclear power sources in outer space. [spacecraft propulsion legal aspects

    NASA Technical Reports Server (NTRS)

    Hosenball, S. N.

    1978-01-01

    Legal problems associated with nuclear power sources in space are discussed with particular reference to the Cosmos 954 incident. Deliberations of the Legal and Scientific and Technical Subcommittees on the Peaceful Uses of Outer Space on this subject are discussed.

  19. Radioisotope Electric Propulsion for Fast Outer Planetary Orbiters

    NASA Technical Reports Server (NTRS)

    Oleson, Steven; Benson, Scott; Gefert, Leon; Patterson, Michael; Schreiber, Jeffrey

    2002-01-01

    Recent interest in outer planetary targets by the Office of Space Science has spurred the search for technology options to enable relatively quick missions to outer planetary targets. Several options are being explored including solar electric propelled stages combined with aerocapture at the target and nuclear electric propulsion. Another option uses radioisotope powered electric thrusters to reach the outer planets. Past work looked at using this technology to provide faster flybys. A better use for this technology is for outer planet orbiters. Combined with medium class launch vehicles and a new direct trajectory these small, sub-kilowatt ion thrusters and Stirling radioisotope generators were found to allow missions as fast as 5 to 12 years for objects from Saturn to Pluto, respectively. Key to the development is light spacecraft and science payload technologies.

  20. Decreasing Outer Hair Cell Membrane Cholesterol Increases Cochlear Electromechanics

    NASA Astrophysics Data System (ADS)

    Brownell, William E.; Jacob, Stefan; Hakizimana, Pierre; Ulfendahl, Mats; Fridberger, Anders

    2011-11-01

    The effect of decreasing membrane cholesterol on the mechanical response of the cochlea to acoustic and/or electrical stimulation was monitored using laser interferometry. In contrast to pharmacological interventions that typically decrease cochlear electromechanics, reducing membrane cholesterol increased the response. The electromechanical response in untreated preparations was asymmetric with greater displacements in response to positive currents and cholesterol depletion increased the asymmetry. The results confirm that outer hair cell electromotility is enhanced by low membrane cholesterol. The asymmetry of the response indicates the outer hair cell resting membrane potential is hyperpolarized relative to the voltage of maximum gain for the outer hair cell voltage-displacement function. The magnitude of the response increase suggests a non-uniform distribution of cholesterol along the lateral wall of normal adult outer hair cells.

  1. 6. OUTER BLAST DOOR, WEST REAR. Edwards Air Force ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. OUTER BLAST DOOR, WEST REAR. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  2. Electron beam seals outer surfaces of porous bodies

    NASA Technical Reports Server (NTRS)

    Herz, W. H.; Kurtz, A. D.; Kurtz, R. A.

    1966-01-01

    Porous tungsten plugs provide even airflow for frictionless bearings used in air bearing supported gyros. The plugs have their outer cylindrical surface sealed by an electron beam process to ensure unidirectional airflow through their exit ends.

  3. Sequence stratigraphy on an early Cretaceous passive margin, Exmouth Plateau

    SciTech Connect

    Boyd, R.; Gorur, N.; Ito, M.; O'Brien, D.; Wilkens, R.; Tang, C.

    1989-03-01

    Permian-Jurassic rifting of northwestern Australia resulted in the development of a passive continental margin flanking the northeastern Indian Ocean. On this margin the relatively thin synrift to postrift sedimentary sequence of southern Exmouth Plateau was drilled during ODP Leg 122. A sequence-stratigraphy analysis of the complete Mesozoic-Cenozoic sedimentary succession at Sites 762 and 763 was derived from a synthesis of seismic stratigraphy, wireline logs, lithostratigraphy, biostratigraphy, and magnetostratigraphy. Results indicate that during breakup, the southern Exmouth Plateau was a transform margin with an extensional component. Between the Tithonian and Valanginian, a thick clastic wedge prograded from the transform margin south of Site 763 northwestward toward Site 762 and onto subsiding continental crust. Southern clastic supply decreased into the Aptian-Cenomanian, and cyclic deposition of deep-water mudstones continued during subsidence of the earlier shelf margin wedge. Between the Albian and Cenomanian, deposition gradually became dominated by pelagic carbonates. Two regional unconformities mark the Cenomanian/Turonian and Cretaceous/Tertiary boundaries. Each was an erosional event, succeeded by renewed pelagic carbonate deposition that began in the distal northern basin and onlapped progressively toward the topographic high, which persisted into the Tertiary along the southern margin. The entire Jurassic to Holocene record at the southern Exmouth Plateau ODP sites is less than 1500 m thick and represents a classic rift to mature ocean passive-margin succession.

  4. Direct observations of the ACC transport across the Kerguelen Plateau

    NASA Astrophysics Data System (ADS)

    Park, Young-Hyang; Vivier, Frédéric; Roquet, Fabien; Kestenare, Elodie

    2009-09-01

    Major pathways and transport of the Antarctic Circumpolar Current (ACC) crossing the Kerguelen Plateau were directly observed during the 2009 Track cruise. The net eastward transport to the south of the Heard/McDonald Islands is estimated as 56 Sv (1 Sv = 106 m3 s-1), 43 Sv of which is tightly channelled into the Fawn Trough that appears as a predominant cross-plateau gateway of circumpolar flow associated with the Southern ACC Front (SACCF). There are also two secondary passages, with one (6 Sv) being attached to the nearshore slope just south of the Heard/McDonald Islands and the other (7 Sv) passing through the northern Princess Elizabeth Trough. With an additional 2 Sv inferred just south of the Kerguelen Islands, the transport across the entire plateau amounts to 58 Sv, accounting for ˜40% of the total ACC transport transiting through the region, 147-152 Sv, quantities consistent with other independent estimates in the Indian sector of the Southern Ocean.

  5. Hexabromocyclododecane in alpine fish from the Tibetan Plateau, China.

    PubMed

    Zhu, Nali; Fu, Jianjie; Gao, Yan; Ssebugere, Patrick; Wang, Yawei; Jiang, Guibin

    2013-10-01

    Hexabromocyclododecanes (HBCDs) has just been listed into Stockholm Convention as a persistent organic pollutant recently. This paper studied the HBCDs in 79 wild fish from high mountain lakes and rivers of the Tibetan Plateau. The ∑HBCDs in fish muscles ranged from non detectable levels to 13.7 ng/g lipid weight (lw) (mean value of 2.12 ng/g lw) with a high detection frequency of 65.8%. α-HBCD dominated among the isomers and accounted for 78.2% of the total burden. Concentrations of ∑HBCDs in the fish were significantly correlated with the lipid content. A decreasing trend was observed between α-HBCD and trophic level. Positive correlation was also noted between the HBCD levels in fish from lakes and the annual precipitation, and this implied the long-range atmospheric transport of HBCDs to the Tibet Plateau. This was the first work to widely explore HBCDs contamination in the aquatic ecosystems of the Tibetan Plateau. PMID:23800423

  6. Mesozoic tectonic features of the Floridan Plateau basement

    SciTech Connect

    Lord, K.M. . Dept. of Geology)

    1993-03-01

    Digitally-filtered Bouguer gravity anomaly maps of the Floridan Plateau delineate the Mesozoic extensional basins in the southwestern half of the plateau and suggest modification of existing basement models. The extension into Florida of the Triassic South Georgia Rift is marked by a gravity low and appears to have small ancillary rift basins paralleling its southeastern border. The Jurassic Apalachicola, Tampa, and South Florida Basins are delineated by positive anomalies, possibly attributable to the emplacement of hypabyssal rocks, and are separated by the negative anomalies of the Middle Ground and Sarasota Arches. The Tampa Basin is more aerially extensive than shown on previous basement maps, extending from the Jay Fault zone to the western edge of the plateau. The South Florida Basin is likely comprised of three separate NW-trending grabens sharing a common northwestern boundary. Existing seismic reflection profiles provide a characterization of some of the boundaries of these features. All of them, with the possible exception of the Apalachicola Basin, are bounded by the Jay Fault zone, a probable Paleozoic right-lateral strike-slip zone, segments of which were reactivated during the Mesozoic to accommodate differential vertical movement related to extension.

  7. Oblique stepwise rise and growth of the Tibet plateau.

    PubMed

    Tapponnier, P; Zhiqin, X; Roger, F; Meyer, B; Arnaud, N; Wittlinger, G; Jingsui, Y

    2001-11-23

    Two end member models of how the high elevations in Tibet formed are (i) continuous thickening and widespread viscous flow of the crust and mantle of the entire plateau and (ii) time-dependent, localized shear between coherent lithospheric blocks. Recent studies of Cenozoic deformation, magmatism, and seismic structure lend support to the latter. Since India collided with Asia approximately 55 million years ago, the rise of the high Tibetan plateau likely occurred in three main steps, by successive growth and uplift of 300- to 500-kilometer-wide crustal thrust-wedges. The crust thickened, while the mantle, decoupled beneath gently dipping shear zones, did not. Sediment infilling, bathtub-like, of dammed intermontane basins formed flat high plains at each step. The existence of magmatic belts younging northward implies that slabs of Asian mantle subducted one after another under ranges north of the Himalayas. Subduction was oblique and accompanied by extrusion along the left lateral strike-slip faults that slice Tibet's east side. These mechanisms, akin to plate tectonics hidden by thickening crust, with slip-partitioning, account for the dominant growth of the Tibet Plateau toward the east and northeast. PMID:11721044

  8. THE STANDARDIZED CANDLE METHOD FOR TYPE II PLATEAU SUPERNOVAE

    SciTech Connect

    Olivares E, Felipe; Hamuy, Mario; Pignata, Giuliano; Maza, Jose; Bersten, Melina; Phillips, Mark M.; Morrel, Nidia I.; Suntzeff, Nicholas B.; Filippenko, Alexei V.; Kirshner, Robert P.; Matheson, Thomas

    2010-06-01

    In this paper, we study the 'standardized candle method' using a sample of 37 nearby (redshift z < 0.06) Type II plateau supernovae having BVRI photometry and optical spectroscopy. An analytic procedure is implemented to fit light curves, color curves, and velocity curves. We find that the V-I color toward the end of the plateau can be used to estimate the host-galaxy reddening with a precision of {sigma}(A{sub V}) = 0.2 mag. The correlation between plateau luminosity and expansion velocity previously reported in the literature is recovered. Using this relation and assuming a standard reddening law (R{sub V} = 3.1), we obtain Hubble diagrams (HDs) in the BVI bands with dispersions of {approx}0.4 mag. Allowing R{sub V} to vary and minimizing the spread in the HDs, we obtain a dispersion range of 0.25-0.30 mag, which implies that these objects can deliver relative distances with precisions of 12%-14%. The resulting best-fit value of R{sub V} is 1.4 {+-} 0.1.

  9. Atmospheric transport of mercury to the Tibetan Plateau.

    PubMed

    Loewen, Mark; Kang, Shichang; Armstrong, Debbie; Zhang, Qianggong; Tomy, Gregg; Wang, Feiyue

    2007-11-15

    The Tibetan Plateau (including the Himalayas) is one of the most remote and cold regions in the world. It has very limited to nonexistent industry but is adjacent to the two most populous and rapidly industrializing countries (China and India) and thus provides a unique location for studying the atmospheric transport of mercury. Here we report the first study on the atmospheric transport of mercury to the Tibetan Plateau. The total mercury profiles in four snowpits from glaciers above 5700 m asl along a southwest-northeast transect across the central Tibetan Plateau were obtained in 2005-2006. In general, the total mercury concentrations in the snow samples ranged from < 1 to 9 ng L(-1), increasing northeastward from the southernmost site at Mount Everest. Higher total mercury concentrations were found in the snow deposited in the nonmonsoon season, as indicated by seasonal variation of delta18O values and major ions in the snowpack. The annual atmospheric depositional flux of total Hg was estimated to range from 0.74 to 2.97 microg m(-2) yr(-1) in the region, the majority of which occurred via particulate matter deposition. PMID:18075067

  10. Dual locked plating of unstable bicondylar tibial plateau fractures.

    PubMed

    Ozkaya, Ufuk; Parmaksizoglu, Atilla Sancar

    2015-07-01

    The operative treatment of displaced bicondylar tibial plateau fractures is challenging. The displaced condyles must be reduced, depressed plateaus must be elevated and adequately supported and early rehabilitation must be encouraged in order to obtain good clinical results. This retrospective study was designed to evaluate the clinical outcomes of patients with bicondylar tibial plateau fractures treated with dual locked plates using raft screws with MIPO technique and autologous bone grafting. We hypothesized that in this group of patients dual locked plating reduces the complication rates by avoiding loss of reduction due to the accomplished rigid fixation. Twenty-two consecutive patients with bicondylar tibial plateau fractures (AO Type C) were included in this study. The mean follow up was 26 months. Bone healing was achieved in all patients with 3 cases of superficial and 1 case of deep infection. Secondary loss of reduction, secondary loss of alignment, early post-traumatic arthritis were not observed in this study. The Lysholm knee score showed an average of 80.5 points (range: 61.5-90) at the final follow up assessment. Optimal fixation of the fracture with dual locked plating which allows immediate motion and partial weight bearing may be an alternative concept to prevent secondary loss of reduction to obtain a good clinical outcome. PMID:26021666

  11. Black carbon radiative forcing over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    He, Cenlin; Li, Qinbin; Liou, Kuo-Nan; Takano, Yoshi; Gu, Yu; Qi, Ling; Mao, Yuhao; Leung, L. Ruby

    2014-11-01

    We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. The annual mean BC snow albedo forcing is 2.9 W m-2 averaged over snow-covered plateau regions, which is a factor of 3 larger than the value over global land snowpack. BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing, and coated BC increases the forcing by 30-50% compared with uncoated BC aggregates, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. The annual BC DRF at the top of the atmosphere is 2.3 W m-2 with uncertainties of -70-85% in the plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network observations. The BC forcings are attributed to emissions from different regions.

  12. Black Carbon Radiative Forcing over the Tibetan Plateau

    SciTech Connect

    He, Cenlin; Li, Qinbin; Liou, K. N.; Takano, Y.; Gu, Yu; Qi, L.; Mao, Yuhao; Leung, Lai-Yung R.

    2014-11-28

    We estimate the snow albedo forcing and direct radiative forcing (DRF) of black carbon (BC) in the Tibetan Plateau using a global chemical transport model in conjunction with a stochastic snow model and a radiative transfer model. Our best estimate of the annual BC snow albedo forcing in the Plateau is 2.9 W m-2 (uncertainty: 1.5–5.0 W m-226 ). We find that BC-snow internal mixing increases the albedo forcing by 40-60% compared with external mixing and coated BC increases the forcing by 30-50% compared with uncoated BC, whereas Koch snowflakes reduce the forcing by 20-40% relative to spherical snow grains. Our best estimate of the annual BC DRF at the top of the atmosphere is 2.3 W m-2 (uncertainty: 0.7–4.3 W m-230 ) in the Plateau after scaling the modeled BC absorption optical depth to Aerosol Robotic Network (AERONET) observations. The BC forcings are attributed to emissions from different regions.

  13. STAR FORMATION IN THE OUTER DISK OF SPIRAL GALAXIES

    SciTech Connect

    Barnes, Kate L.; Van Zee, Liese; Cote, Stephanie; Schade, David E-mail: vanzee@astro.indiana.edu E-mail: David.Schade@nrc-cnrc.gc.ca

    2012-09-20

    We combine new deep and wide field of view H{alpha} imaging of a sample of eight nearby (d Almost-Equal-To 17 Mpc) spiral galaxies with new and archival H I and CO imaging to study the star formation and the star formation regulation in the outer disk. We find that, in agreement with previous studies, star formation in the outer disk has low covering fractions, and star formation is typically organized into spiral arms. The star formation in the outer disk is at extremely low levels, with typical star formation rate surface densities of {approx}10{sup -5} to 10{sup -6} M{sub Sun} yr{sup -1} kpc{sup -2}. We find that the ratio of the radial extent of detected H II regions to the radius of the H I disk is typically {approx}>85%. This implies that in order to further our understanding of the implications of extended star formation, we must further our understanding of the formation of extended H I disks. We measure the gravitational stability of the gas disk, and find that the outer gaseous disk is typically a factor of {approx}2 times more stable than the inner star-forming disk. We measure the surface density of outer disk H I arms, and find that the disk is closer to gravitational instability along these arms. Therefore, it seems that spiral arms are a necessary, but not sufficient, requirement for star formation in the outer disk. We use an estimation of the flaring of the outer gas disk to illustrate the effect of flaring on the Schmidt power-law index; we find that including flaring increases the agreement between the power-law indices of the inner and outer disks.

  14. Proteome analysis of mitochondrial outer membrane from Neurospora crassa

    SciTech Connect

    Schmitt, Simone; Prokisch, Holger; Schlunk, Tilman; Camp, David G.; Ahting, Uwe; Waizenegger, Thomas; Scharfe, Curt M.; Meitinger, Thomas; Imhof, Axel; Neupert, Walter; Oefner, Peter J.; Rapaport, Doron

    2006-01-01

    The mitochondrial outer membrane mediates numerous interactions between the metabolic and genetic systems of mitochondria and the rest of the eukaryotic cell. We performed a proteomic study to discover novel functions of components of the mitochondrial outer membrane. Proteins of highly pure outer membrane vesicles (OMV) from Neurospora crassa were identified by a combination of liquid chromatography tandem mass spectrometry of tryptic peptide digests and gel electrophoresis of solubilized OMV proteins, followed by their identification using MALDI-MS peptide fingerprinting. Among the 30 proteins found in at least three of four separate analyses were 23 proteins with known functions in the outer membrane. These included components of the import machinery (the TOM and TOB complexes), a pore-forming component (Porin), and proteins that control fusion and fission of the organelle. In addition, proteins playing a role in various biosynthetic pathways, whose intracellular location had not been established previously, could be localized to the mitochondrial outer membrane. Thus, the proteome of the outer membrane can help in identifying new mitochondria-related functions.

  15. Climatology of monsoon precipitation over the Tibetan Plateau from 13-year TRMM observations

    NASA Astrophysics Data System (ADS)

    Aijuan, Bai; Guoping, Li

    2015-07-01

    Based on the 13-year data from the Tropical Rainfall Measuring Mission (TRMM) satellite during 2001-2013, the influencing geographical location of the Tibetan Plateau (Plateau) monsoon is determined. It is found that the domain of the Plateau monsoon is bounded by the latitude between 27° N and 37° N and the longitude between 60° E and 103° E. According to the annual relative precipitation, the Plateau monsoon can be divided into three sections: the Plateau winter monsoon (PWM) over Iran and Afghanistan, the Plateau summer monsoon (PSM) over the central Plateau, and the transiting zone of the Plateau monsoon (TPM) over the south, west, and east edges of the Plateau. In PWM and PSM, the monsoon climatology has a shorter rainy season with the mean annual rainfall of less than 800 mm. In TPM, it has a longer rainy season with the mean annual rainfall of more than 1800 mm. PWM experiences a single-peak monthly rainfall with the peak during January to March; PSM usually undergoes a multi-peak pattern with peaks in the warm season; TPM presents a double-peak pattern, with a strong peak in late spring to early summer and a secondary peak in autumn. The Plateau monsoon also characterizes an asymmetrical seasonal advance of the rain belt. In the east of the Plateau, the rain belt migrates in a south-north orientation under the impact of the tropical and subtropical systems' oscillation. In the west of the Plateau, the rain belt advances in an east-west direction, which is mainly controlled by the regional Plateau monsoon.

  16. Pliocene Volcanic Evolution of the Taos Plateau, New Mexico

    NASA Astrophysics Data System (ADS)

    Cosca, M. A.; Thompson, R. A.; Turner, K. J.; Lee, J. P.

    2012-12-01

    New geologic mapping (1:24k-1:50k scale) and high precision 40Ar/39Ar geochronology of volcanic rocks from the Taos Plateau in northern New Mexico reveals nearly 4 million years of predominantly mafic (basalt to andesite) volcanism associated with the Pliocene to Quaternary Rio Grande rift. A nearly continuous record of volcanism is recorded from ~5 to ~1 Ma with two major pulses of magmatism observed at ~4.5 Ma and ~3 Ma reflecting eruption from more than 50 mapped centers and an unresolved number of centers buried by intercalated rift volcanics and sedimentary basin fill. Volcanism, both outflow thickness and vent locations, is strongly controlled by the same north to northwest trending fault systems defining the Rio Grande rift graben. However, active loci of volcanism can be linked to sub-basins within the broader graben structure. Large composite volcanoes ranging in composition from basaltic andesite to andesite, such as Guadeloupe Mountain (~4.5-5 Ma), Ute Mountain (~3.9 Ma), and San Antonio Mountain (~3 Ma) formed over time intervals of about 300 ka during the most voluminous stages of activity. Similar time intervals are recorded in each of three Servilleta basalt flow packages (lower (~4.5 Ma), middle (~4 Ma), and upper (~3.5 Ma)) observed at the Rio Grande gorge just north of Taos that first began erupting at ~ 4.7 Ma. Distinctive reddish paleosols between each Servilleta flow package represent time intervals between eruptions of ~0.5 Ma. Late stage volcanic activity (< 3 Ma) is recorded as small volume Servilleta basalt volcanoes and numerous small basalt to basaltic andesite cinder cones and associated lavas flows. Mesita Cone, dated at ~ 1 Ma and offset by middle Pleistocene faulting, represents the youngest volcanic activity within the Taos plateau segment of the Rio Grande Rift. The Pliocene to Quaternary volcanic rocks of the Taos Plateau are locally underlain by 1) Precambrian crystalline granite basement, 2) Oligocene calc-alkaline volcanic and

  17. Soil moisture balance and magnetic enhancement in loess-paleosol sequences from the Tibetan Plateau and Chinese Loess Plateau

    NASA Astrophysics Data System (ADS)

    Hu, Pengxiang; Liu, Qingsong; Heslop, David; Roberts, Andrew P.; Jin, Chunsheng

    2015-01-01

    We present a first combined environmental magnetic and geochemical investigation of a loess-paleosol sequence (<55 ka) from the Chuanxi Plateau on the eastern margin of the Tibetan Plateau. Detailed comparison between the Ganzi section and the Luochuan section from the Chinese Loess Plateau (CLP) allows quantification of the effects of provenance and climate on pedogenic magnetic enhancement in Chinese loess. Rare earth element patterns and clay mineral compositions indicate that the Ganzi loess originates from the interior of the Tibetan Plateau. The different Ganzi and CLP loess provenances add complexity to interpretation of magnetic parameters in terms of the concentration and grain size of eolian magnetic minerals. Enhanced paleosol magnetism via pedogenic formation of ferrimagnetic nanoparticles is observed in both sections, but weaker ferrimagnetic contributions, finer superparamagnetic (SP) particles and stronger chemical weathering are found in the Ganzi loess, which indicates the action of multiple pedogenic processes that are dominated by the combined effects of mean annual precipitation (MAP), potential evapotranspiration (PET), organic matter and aluminium content. Under relatively high MAP and low PET conditions, high soil moisture favours transformation of ferrimagnetic minerals to hematite, which results in a relatively higher concentration of hematite but weaker ferrimagnetism of Ganzi loess. Initial growth of superparamagnetic (SP) particles is also documented in the incipient loess at Ganzi, which directly reflects the dynamic formation of nano-sized pedogenic ferrimagnets. A humid pedogenic environment with more organic matter and higher Al content also helps to form finer SP particles. We therefore propose that soil water balance, rather than solely rainfall, dominates the type, concentration and grain size of secondary ferrimagnetic minerals produced by pedogenesis.

  18. Geomorphological significance of the palaeodrainage network on a karst plateau: The Una-Korana plateau, Dinaric karst, Croatia

    NASA Astrophysics Data System (ADS)

    Bočić, Neven; Pahernik, Mladen; Mihevc, Andrej

    2015-10-01

    Karst plateaus often have a complex geological and geomorphological history. It is widely accepted that their development requires a long period of karst denudation. This study reconstructs the palaeodrainage network of a karst plateau, analyses its properties and establishes its geomorphological significance. The main purpose of this research was to deepen our understanding of a key stage in the evolution of karst plateaus - the transition from a fluvial land surface to one dominated by karst surface processes. The study was conducted on a large part of the Una-Korana plateau, the largest plateau in the Dinaric karst. The majority of the plateau is made of carbonate rocks of Triassic, Jurassic and Cretaceous age that set the conditions for the development of the karst. We have reconstructed the palaeodrainage network based on 1:25,000 topographic maps with 10 m contours. The transition of the surface drainage network to the underground karst drainage network is still in progress, so, depending on the degree of karstification, the drainage network was divided into three categories: active, dry and relict. It was found that 90.5% of the pre-existing drainage network has undergone some degree of karstification. The active surface drainage network gradually shifted to a dry network, then to a relict network. The surface drainage network is gradually replaced by a dense network of dolines. Today, the flat and karstified inter-fluvial area is drained underground towards the main watercourses and these drain the entire region over the surface towards the Pannonian basin. This is the largest known karst palaeodrainage network in the Dinaric karst that has been reconstructed in this way.

  19. Early Human Occupation on the Northeast Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Rhode, D.; Madsen, D.; Brantingham, P.; Perrault, C.

    2010-12-01

    The Tibetan Plateau presents great challenges for human occupation: low oxygen, high ultraviolet radiation, harsh seasonal climate, low overall biological productivity. How and when early humans were able to cope physiologically, genetically, and behaviorally with these extremes is important for understanding the history of human adaptive flexibility. Our investigations of prehistoric human settlement on the northeast Tibetan Plateau focus on (a) establishing well-dated evidence for occupation of altitudes >3000 m, (b) the environmental context of high altitude adaptation, and (c) relations of hunting and pastoralism to lower-altitude agrarian systems. We observe two major prehistoric settlement patterns in the Qinghai Lake area. The earliest, ~15,000-7500 yr old, consists of small isolated firehearths with sparse associated stone tools and wild mammal remains (1). Numerous hearths often occur in the same localities, indicating repeated short-duration occupations by small hunting parties. A second pattern, ~9000-4000 yr old, was established during the Holocene climatic optimum. These sites represent prolonged seasonal residential occupation, containing dark anthropogenic midden, hearth and pit constructions, abundant stone tools, occasional ceramics, and abundant diverse faunal remains (including medium-large mammals but lacking domestic sheep/yak)(2). These Plateau-margin base camps allowed greater intensity of use of the high Plateau. Residential occupation was strongly influenced by nearby lower-altitude farming communities; development of the socioeconomic landscape along the Yellow River likely played at least as great a role in Plateau occupation patterns as did Holocene environmental changes. Holocene vegetation changes in the NE Tibetan Plateau have been attributed to climate (3) or anthropogenic modification (4). Our results document changes in shrub/tree presence from ~12,000-4000 BP, similar to pollen records, that likely reflect climate rather than

  20. 75 FR 7515 - Environmental Documents Prepared for Proposed Mineral Exploration on the Alaska Outer Continental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... Outer Continental Shelf AGENCY: Minerals Management Service (MMS), Interior. ACTION: Notice of the... proposed on the Alaska Outer Continental Shelf (OCS). FOR FURTHER INFORMATION CONTACT: Minerals...

  1. Into Tibet: An Early Pliocene Dispersal of Fossil Zokor (Rodentia: Spalacidae) from Mongolian Plateau to the Hinterland of Tibetan Plateau

    PubMed Central

    Li, Qiang; Wang, Xiaoming

    2015-01-01

    This paper reports the fossil zokors (Myospalacinae) collected from the lower Pliocene (~4.4 Ma) of Zanda Basin, southwestern Tibet, which is the first record in the hinterland of Tibetan Plateau within the Himalayan Range. Materials include 29 isolated molars belonging to Prosiphneus eriksoni (Schlosser, 1924) by having characters including large size, highly fused roots, upper molars of orthomegodont type, m1 anterior cap small and centrally located, and first pair of m1 reentrants on opposing sides, high crowns, and high value of dentine tract parameters. Based on the cladistics analysis, all seven species of Prosiphneus and P. eriksoni of Zanda form a monophyletic clade. P. eriksoni from Zanda, on the other hand, is nearly the terminal taxon of this clade. The appearance of P. eriksoni in Zanda represents a significant dispersal in the early Pliocene from its center of origin in north China and Mongolian Plateau, possibly via the Hol Xil-Qiangtang hinterland in northern Tibet. The fast evolving zokors are highly adapted to open terrains at a time when regional climates had become increasingly drier in the desert zones north of Tibetan Plateau during the late Miocene to Pliocene. The occurrence of this zokor in Tibet thus suggests a rather open steppe environment. Based on fossils of large mammals, we have formulated an “out of Tibet” hypothesis that suggests earlier and more primitive large mammals from the Pliocene of Tibet giving rise to the Ice Age megafauna. However, fossil records for large mammals are still too poor to evaluate whether they have evolved from lineages endemic to the Tibetan Plateau or were immigrants from outside. The superior record of small mammals is in a better position to address this question. With relatively dense age intervals and numerous localities in much of northern Asia, fossil zokors provide the first example of an “into Tibet” scenario–earlier and more primitive taxa originated from outside of the Tibetan Plateau

  2. Seismic reflection data support episodic and simultaneous growth of the Tibetan Plateau since 25 Myr.

    PubMed

    Jiang, Xiao-Dian; Li, Zheng-Xiang

    2014-01-01

    The spectacular topography of the Tibetan Plateau is the result of collision between India and Eurasia over some 50 Myr, but how the plateau grew to its present size remains a topic of debate. Work along its eastern margin suggests a two-stage uplift (thus growth of the plateau) since 30-25 Myr. Here we report high-resolution seismic reflection and drill core results from the southern Tarim Basin that indicate a similar pattern for the northern margin of the plateau. The data suggest that uplift in northern Tibet started at ~23 Myr from near sea level, with the first episode finished by ~10 Myr, followed by a post-5-Myr episode of rapid uplift along the present plateau margin. The growth of the Tibetan Plateau after the Eocene thus appears to have been episodic in nature, and near-synchronous along both eastern and northern margins. PMID:25391269

  3. Four Flavours of Orogenic Plateau Magmatism: What's Melting Beneath the Turkish-Iranian Plateau?

    NASA Astrophysics Data System (ADS)

    Neill, I.; Allen, M. B.; Kaislaniemi, L.; Van Hunen, J.

    2013-12-01

    Orogenic plateaux are first order topographic features of the continents, occurring in collision zones such as Tibet and Andean-style continental arcs. Plateaux are sites of abundant mantle-derived magmatism, but there is little understanding of its geodynamic cause in spite of assumptions that slab break-off or lithospheric thinning are controlling factors in melt production. The Turkish-Iranian Plateau formed on the Eurasian Plate after the ~30 Ma Arabia-Eurasia collision. Neogene-recent volcanoes are found up to ~800 km from the suture, and have huge compositional variation. We define four varieties of recent mafic magmatism spatially and geochemically. (1) Close to the Bitlis Suture in Eastern Turkey, slab break-off is likely to have occurred at ~10 Myr, and there is little mantle lithosphere present. Magmatism is mostly calc-alkaline, sourced from the asthenosphere or any remaining mantle lithosphere, and is affected by crustal contamination. (2) In the Lesser Caucasus up to ~500 km from the suture, magmatism is more alkaline, less crustally-contaminated and is derived from subduction-modified lithospheric mantle. (3) Close to the Zagros Suture in Iran, the lithosphere may have thickened to >200 km during collision. Magmatism is volumetrically limited and derived almost exclusively from the lithospheric mantle, with trace element-enriched alkaline or ultrapotassic compositions. Unlike the Lesser Caucasus, there is little magmatism in the Iranian desert up to ~500 km from the suture. (4) Beyond ~500 km from the Bitlis-Zagros Suture Zone, there is sparse, compositionally variable magmatism: it is OIB-like in Eastern Iran, more akin to Zagros magmatism in the Alborz, and more felsic above the ~55 km thick crust of the Greater Caucasus. Geochemical data suggest that magmatism in (1) is caused by asthenospheric upwelling following slab breakoff, whereas in (2) it is dominated by melting of the base of the still-present lithospheric mantle during convective removal

  4. Spiny neurons of amygdala, striatum, and cortex use dendritic plateau potentials to detect network UP states

    PubMed Central

    Oikonomou, Katerina D.; Singh, Mandakini B.; Sterjanaj, Enas V.; Antic, Srdjan D.

    2014-01-01

    Spiny neurons of amygdala, striatum, and cerebral cortex share four interesting features: (1) they are the most abundant cell type within their respective brain area, (2) covered by thousands of thorny protrusions (dendritic spines), (3) possess high levels of dendritic NMDA conductances, and (4) experience sustained somatic depolarizations in vivo and in vitro (UP states). In all spiny neurons of the forebrain, adequate glutamatergic inputs generate dendritic plateau potentials (“dendritic UP states”) characterized by (i) fast rise, (ii) plateau phase lasting several hundred milliseconds, and (iii) abrupt decline at the end of the plateau phase. The dendritic plateau potential propagates toward the cell body decrementally to induce a long-lasting (longer than 100 ms, most often 200–800 ms) steady depolarization (∼20 mV amplitude), which resembles a neuronal UP state. Based on voltage-sensitive dye imaging, the plateau depolarization in the soma is precisely time-locked to the regenerative plateau potential taking place in the dendrite. The somatic plateau rises after the onset of the dendritic voltage transient and collapses with the breakdown of the dendritic plateau depolarization. We hypothesize that neuronal UP states in vivo reflect the occurrence of dendritic plateau potentials (dendritic UP states). We propose that the somatic voltage waveform during a neuronal UP state is determined by dendritic plateau potentials. A mammalian spiny neuron uses dendritic plateau potentials to detect and transform coherent network activity into a ubiquitous neuronal UP state. The biophysical properties of dendritic plateau potentials allow neurons to quickly attune to the ongoing network activity, as well as secure the stable amplitudes of successive UP states. PMID:25278841

  5. A preliminary study of the heating effect of the Tibetan Plateau.

    PubMed

    Yao, Yonghui; Zhang, Baiping

    2013-01-01

    The immense and towering Tibetan Plateau acts as a heating source and, thus, deeply shapes the climate of the Eurasian continent and even the whole world. However, due to the scarcity of meteorological observation stations and very limited climatic data, little is quantitatively known about the heating effect of the plateau and its implications. This paper firstly collects climate data (2001-2007) from 109 observation stations and MODIS-based estimated monthly mean temperature data in the plateau and the neighboring Sichuan Basin, and conducts correlation and simple linear regression to reveal the altitudinal pattern of temperature. Then, according to the linear relationships of temperature and altitude for each month, it compares air temperature differences on the same elevation between the main plateau and surrounding mountains and the Sichuan Basin so as to quantify the heating effect and discuss its implication on timberline of the plateau. The results show that: 1) the heating effect of the plateau is significant. The temperature of the main plateau area was higher than that of free air on the same elevation above the neighboring areas; on the elevation of 4500 m (the main plateau), temperature is 1-6°C higher in the main Plateau than over the Sichuan Basin for different months and 5.9-10.7°C higher than in the Qilian Mountains in the northeastern corner of the plateau. 2) Even at altitudes of 5000-6000 m in the main Plateau, there are 4 months with a mean temperature above 0°C. The mean temperature of the warmest month (July) can reach 10°C at about 4600-4700 m. This may help explain why the highest timberline in the northern hemisphere is on the southeastern Tibetan Plateau. PMID:23935886

  6. M = 1 internal kink mode in the plateau and banana regimes in tokamaks

    SciTech Connect

    Mikhailovskii, A.B.; Tsypin, V.S.

    1983-01-01

    A theory is derived for the m = 1 internal kink mode of a tokamak in the plateau and banana regimes. The growth rate for this mode in the plateau regime is shown to be smaller by a factor of a/R than the MHD prediction (a and R are the minor and major radii of the torus). The growth rate in the banana regime is higher than in the plateau regime and approaches the standard MHD value.

  7. Paleoenvironmental analysis and correlation of a Cretaceous Islas Orcadas core from the Falkland Plateau, Southwest Atlantic

    USGS Publications Warehouse

    Ciesielski, P.F.; Sliter, W.V.; Wind, F.H.; Wise, S.W., Jr.

    1977-01-01

    A comparison of Campanian-Maestrichtian cores from two localities on opposite sides of the Maurice Ewing Bank, at the eastern end of the east-west trending Falkland Plateau (Southwest Atlantic) reveals a significant change in faunal and floral assemblage characteristics across the Plateau. These changes are probably temperature dependent, and indicate that the Plateau served as an important barrier between water masses in the South Atlantic during late Cretaceous times. ?? 1977.

  8. An Outer Arm in the Second Galactic Quadrant: Structure

    NASA Astrophysics Data System (ADS)

    Du, Xinyu; Xu, Ye; Yang, Ji; Sun, Yan; Li, Facheng; Zhang, Shaobo; Zhou, Xin

    2016-05-01

    The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l = [100, 150]°, b = [‑3, 5]° has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas—this is the first time that the Outer arm has been reported in such a large-scale mapping of molecular gas. Using the 115 GHz 12CO(1–0) data of MWISP at the LSR velocity ≃[‑100, ‑60] km s‑1 and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ˜3.1 × 106 M ⊙. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ˜13.°1. Besides combining both the CO data from MWISP and the 21 cm H i data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.

  9. How The Inner Disk Communicates to the Outer Disk

    NASA Astrophysics Data System (ADS)

    Goto, Miwa

    2009-08-01

    We investigated how evolution in the outer disk has an influence on the inner disk of a protoplanetary disk system. Thanks to two-layer models that give the theoretical platform of disk geometry, we now have a good handle on how dust evolves in outer protoplanetary disks (>10 AU). It has long been thought that the outer and inner disks dissipate on roughly the same time scale as sub-mm observations of nearby T Tauri systems has suggested. However, new high spatial resolution observations point toward the dissipation of an inner disk as not being a simple extension of the outer disk. We performed preliminary tests of the differential disk evolution in gas and dust in the inner disks of Herbig Ae/Be stars using the CO vibrational band as the gas probe. The line luminosity of CO v = 1-0 P(30) has a reasonable correlation with the near-infrared excess over the stellar photosphere. It guarantees that the CO vibration band is a secure probe of the inner disk, as is expected from its high critical density, high excitation temperature, and kinematics. On the other hand, the line luminosity of P(30) does not show a clear trend either with far-infrared color, near-infrared/far-infrared-color, or the type of the spectral energy distribution (SED) (I/II). The inner disks (<1 AU) of Herbig Ae/Be stars of our sample are influenced little by the geometry of the outer disks.

  10. Outer Retinal Structure Following Closed Globe Blunt Ocular Trauma

    PubMed Central

    Flatter, John A.; Cooper, Robert F.; Dubow, Michael J.; Pinhas, Alexander; Singh, Ravi S.; Kapur, Rashmi; Shah, Nishit; Walsh, Ryan D.; Hong, Sang H.; Weinberg, David V.; Stepien, Kimberly E.; Wirostko, William J.; Robison, Scott; Dubra, Alfredo; Rosen, Richard B.; Connor, Thomas B.; Carroll, Joseph

    2014-01-01

    Purpose To evaluate outer retinal structural abnormalities in patients with visual deficits following closed globe blunt ocular trauma (cgBOT). Methods Nine subjects with visual complaints following cgBOT were examined between 1 month post-trauma and 6 years post-trauma. Spectral domain optical coherence tomography (SD-OCT) was used to assess outer retinal architecture, while adaptive optics scanning light ophthalmoscopy (AOSLO) was used to analyze photoreceptor mosaic integrity. Results Visual deficits ranged from central scotomas to decreased visual acuity. SD-OCT defects included focal foveal photoreceptor lesions, variable attenuation of the interdigitation zone, and mottling of the outer segment band, with one subject having normal outer retinal structure. AOSLO revealed disruption of the photoreceptor mosaic in all subjects, variably manifesting as foveal focal discontinuities, perifoveal hyporeflective cones, and paracentral regions of selective cone loss. Conclusions We observe persistent outer retinal disruption in subjects with visual complaints following cgBOT, albeit to a variable degree. AOSLO imaging allows assessment of photoreceptor structure at a level of detail not resolvable using SD-OCT or other current clinical imaging tools. Multimodal imaging appears useful for revealing the cause of visual complaints in patients following cgBOT. Future studies are needed to better understand how photoreceptor structure changes longitudinally in response to various trauma. PMID:24752010

  11. An Outer Arm in the Second Galactic Quadrant: Structure

    NASA Astrophysics Data System (ADS)

    Du, Xinyu; Xu, Ye; Yang, Ji; Sun, Yan; Li, Facheng; Zhang, Shaobo; Zhou, Xin

    2016-05-01

    The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l = [100, 150]°, b = [‑3, 5]° has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas—this is the first time that the Outer arm has been reported in such a large-scale mapping of molecular gas. Using the 115 GHz 12CO(1–0) data of MWISP at the LSR velocity ≃[‑100, ‑60] km s‑1 and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ∼3.1 × 106 M ⊙. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ∼13.°1. Besides combining both the CO data from MWISP and the 21 cm H i data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.

  12. Blake Plateau: control of Miocene sedimentation patterns by large- scale shifts of the Gulf Stream axis.

    USGS Publications Warehouse

    Pinet, P.R.; Popenoe, P.

    1982-01-01

    The distribution of buried channel networks within Cenozoic sequences of the Blake Plateau and their correlation with global sea-level oscillations indicate that the Gulf Stream axis shifted landward against the Florida-Hatteras Slope during sea-level highstands and seaward across the central Blake Plateau during sea-level lowstands. A sedimentation model incorporating axial shifts of the Gulf Stream successfully predicts the Miocene stratigraphy of the Florida-Hatteras Slope and Blake Plateau as defined by seismic and drill-hole data. -Authors Cenozoic sequences Blake Plateau sea level oscillations North Atlantic

  13. Plateau growth around the Changma Basin in NE Tibet

    NASA Astrophysics Data System (ADS)

    Vernon, Rowan; Cunningham, Dickson; Zhang, Jin; England, Richard

    2014-05-01

    The Qilian Mountains form one of the most actively uplifting regions of the northeastern Tibetan Plateau and provide an opportunity to study the ongoing, intermediate stages of plateau growth. The crust of the Qilian Mountains consists of an orogenic collage of mid-Proterozoic to mid-Palaeozoic island arc terranes accreted to the North China Craton during the Palaeozoic. NE-directed compression related to the Indo-Asian collision began in the Early Neogene, uplifting fold-thrust mountain ranges which splay south-eastwards from the sinistral northeast-trending Altyn Tagh Fault (ATF). In this study, we investigate the post-Oligocene tectonic evolution of the northern margin of the Tibetan Plateau around the Changma Basin, at the very northeast corner of the Plateau, where the ATF forms a triple junction with the frontal Qilian Shan thrust. Our research involves synthesis of previous geological and geophysical data, remote sensing analysis and field mapping of structures along key transects. The Changma Basin is a relatively low intra-montane basin in the northeast Tibetan Plateau that is receiving alluvial infill from surrounding ranges, but is also being drained by the Su Le River, one of the largest river systems in the northeast Tibetan Plateau. The basin is also internally deforming and inverting along fault and fold zones, as well as being overthrust along some of its margins. Where older basement trends are parallel to neotectonic faults, some reactivation is inferred and locally documented through field observations. Otherwise, the post-Oligocene thrust and oblique-slip faults which are responsible for uplifting various basement blocks and inverting the Changma Basin appear discordant to nearby basement trends. Range-bounding thrust faults with the greatest along-strike continuity and relief generation are assumed to have the largest displacements, whereas other intra-range thrusts that bound uplifted limestone blocks are assumed to have lower amounts of

  14. FINAL FRONTIER AT HANFORD TACKLING THE CENTRAL PLATEAU

    SciTech Connect

    GERBER MS

    2008-03-04

    The large land area in the center of the vast Department of Energy (DOE) Hanford Site in southeast Washington State is known as 'the plateau'--aptly named because its surface elevations are 250-300 feet above the groundwater table. By contrast, areas on the 585-square mile Site that border the Columbia River sit just 30-80 feet above the water table. The Central Plateau, which covers an ellipse of approximately 70 square miles, contains Hanford's radiochemical reprocessing areas--the 200 East and 200 West Areas--and includes the most highly radioactive waste and contaminated facilities on the Site. Five 'canyons' where chemical processes were used to separate out plutonium (Pu), 884 identified soil waste sites (including approximately 50 miles of solid waste burial trenches), more than 900 structures, and all of Hanford's liquid waste storage tanks reside in the Central Plateau. (Notes: Canyons is a nickname given by Hanford workers to the chemical reprocessing facilities. The 177, underground waste tanks at Hanford comprise a separate work scope and are not under Fluor's management). Fluor Hanford, a DOE prime cleanup contractor at the Site for the past 12 years, has moved aggressively to investigate Central Plateau waste sites in the last few years, digging more than 500 boreholes, test pits, direct soil 'pushes' or drive points; logging geophysical data sets; and performing electrical-resistivity scans (a non-intrusive technique that maps patterns of sub-surface soil conductivity). The goal is to identify areas of contamination areas in soil and solid waste sites, so that cost-effective and appropriate decisions on remediation can be made. In 2007, Fluor developed a new work plan for DOE that added 238 soil waste-site characterization activities in the Central Plateau during fiscal years (FYs) 2007-2010. This number represents a 50 percent increase over similar work previously done in central Hanford. Work Plans are among the required steps in the Comprehensive

  15. S-wave velocity structure in the SE Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Cai, Yan; Wu, Jianping; Wang, Weilai; Fang, Lihua; Fan, Liping

    2016-05-01

    We use observations recorded by 23 permanent and 99 temporary stations in the SE Tibetan plateau to obtain the S-wave velocity structure along two profiles by applying joint inversion with receiver functions and surface waves. The two profiles cross West Yunnan block (WYB), the Central Yunnan sub-block (CYB), South China block (SCB), and Nanpanjiang basin (NPB). The profile at ~25°N shows that the Moho interface in the CYB is deeper than those in the WYB and the NPB, and the topography and Moho depth have clear correspondence. Beneath the Xiaojiang fault zone (XJF), there exists a crustal low-velocity zone (LVZ), crossing the XJF and expanding eastward into the SCB. The NPB is shown to be of relatively high velocity. We speculate that the eastward extrusion of the Tibetan plateau may pass through the XJF and affect its eastern region, and is resisted by the rigid NPB, which has high velocity. This may be the main cause of the crustal thickening and uplift of the topography. In the Tengchong volcanic area, the crust is shown to have alternate high- and low-velocity layers, and the upper mantle is shown to be of low velocity. We consider that the magma which exists in the crust is from the upper mantle and that the complex crustal velocity structure is related to magmatic differentiation. Between the Tengchong volcanic area and the XJF, the crustal velocity is relatively high. Combining these observations with other geophysical evidence, it is indicated that rock strength is high and deformation is weak in this area, which is why the level of seismicity is quite low. The profile at ~23°N shows that the variation of the Moho depth is small from the eastern rigid block to the western active block with a wide range of LVZs. We consider that deformation to the south of the SE Tibetan Plateau is weak.

  16. S-wave velocity structure in the SE Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Cai, Yan; Wu, Jianping; Wang, Weilai; Fang, Lihua; Fan, Liping

    2016-06-01

    We use observations recorded by 23 permanent and 99 temporary stations in the SE Tibetan plateau to obtain the S-wave velocity structure along two profiles by applying joint inversion with receiver functions and surface waves. The two profiles cross West Yunnan block (WYB), the Central Yunnan sub-block (CYB), South China block (SCB), and Nanpanjiang basin (NPB). The profile at ~25°N shows that the Moho interface in the CYB is deeper than those in the WYB and the NPB, and the topography and Moho depth have clear correspondence. Beneath the Xiaojiang fault zone (XJF), there exists a crustal low-velocity zone (LVZ), crossing the XJF and expanding eastward into the SCB. The NPB is shown to be of relatively high velocity. We speculate that the eastward extrusion of the Tibetan plateau may pass through the XJF and affect its eastern region, and is resisted by the rigid NPB, which has high velocity. This may be the main cause of the crustal thickening and uplift of the topography. In the Tengchong volcanic area, the crust is shown to have alternate high- and low-velocity layers, and the upper mantle is shown to be of low velocity. We consider that the magma which exists in the crust is from the upper mantle and that the complex crustal velocity structure is related to magmatic differentiation. Between the Tengchong volcanic area and the XJF, the crustal velocity is relatively high. Combining these observations with other geophysical evidence, it is indicated that rock strength is high and deformation is weak in this area, which is why the level of seismicity is quite low. The profile at ~23°N shows that the variation of the Moho depth is small from the eastern rigid block to the western active block with a wide range of LVZs. We consider that deformation to the south of the SE Tibetan Plateau is weak.

  17. Resistivity plateau and extreme magnetoresistance in LaSb

    NASA Astrophysics Data System (ADS)

    Tafti, F. F.; Gibson, Q. D.; Kushwaha, S. K.; Haldolaarachchige, N.; Cava, R. J.

    2016-03-01

    Time reversal symmetry (TRS) protects the metallic surface modes of topological insulators (TIs). The transport signature of such surface states is a plateau that arrests the exponential divergence of the insulating bulk with decreasing temperature. This universal behaviour is observed in all TI candidates ranging from Bi2Te2Se to SmB6. Recently, extreme magnetoresistance (XMR) has been reported in several topological semimetals which exhibit TI universal resistivity behaviour only when breaking time reversal symmetry, a regime where TIs theoretically cease to exist. Among these materials, TaAs and NbP are nominated as Weyl semimetals owing to their lack of inversion symmetry, Cd3As2 is known as a Dirac semimetal owing to its linear band crossing at the Fermi level, and WTe2 is termed a resonant compensated semimetal owing to its perfect electron-hole symmetry. Here we introduce LaSb, a simple rock-salt structure material that lacks broken inversion symmetry, perfect linear band crossing, and perfect electron-hole symmetry yet exhibits all the exotic field-induced behaviours of these more complex semimetals. It shows a field-induced universal TI resistivity with a plateau at roughly 15 K, ultrahigh mobility of carriers in the plateau region, quantum oscillations with the angle dependence of a two-dimensional Fermi surface, and XMR of about one million percent at 9 T. Owing to its structural simplicity, LaSb represents an ideal model system to formulate a theoretical understanding of the exotic consequences of breaking time reversal symmetry in topological semimetals.

  18. Late Cretaceous tectonic framework of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Wu, Zhenhan; Barosh, Patrick J.; Ye, Peisheng; Hu, Daogong

    2015-12-01

    New research, coupled with previous data, reveals the Late Cretaceous paleo-geography, and related paleo-tectonic movement of the Tibetan Plateau. A vast ocean, the Neo-Tethys Ocean, perhaps as wide as ∼7000 km, existed between the Indian and Eurasian Continental Plates in the early Late Cretaceous. In addition, a Himalaya Marginal Sea lay along the border of the Indian Plate and other marginal seas were present to the north in both the southern Lhasa and southwestern Tarim Blocks. Northward subduction of the Neo-Tethys Oceanic Plate along the Yalung-Zangbu Suture closed most of the ocean and led to intensive thrusting, tight folding, magmatic plutonism and volcanic eruptions in the central plateau to the north. A magmatic arc up to 500 km wide formed across the southern margin of the continental plate in central Tibet and its varying granitic composition appears to reflect the depth to the subducted plate and define its geometry. A series of large, chiefly north-dipping thrust systems also developed across central Tibet. These include thrusts along the Yalung-Zangbu and Bangong-Nujiang Sutures, the North Gangdese and North Lhasa Thrusts in the Lhasa Block, the Qiangtang and North Tangula Thrusts in the Qiangtang block, the Hoh-Xil and Bayan Har Thrusts in the Hoh-Xil Block, as well as the sinistral-slip South Kunlun and Altyn Tagh Faults in northern Tibet. Uplifts formed above the hanging walls of the major thrusts and their eroded debris formed thick red-beds in basins below them. The central Tibetan Plateau maintained a low elevation and coastal vegetation was dominant during the Late Cretaceous.

  19. [Spatiotemporal pattern of alpine grassland productivity in Qiangtang Plateau].

    PubMed

    Wang, Jing-Sheng; Zhang, Xian-Zhou; Zhao, Yu-Ping; Qin, Si-Guo; Wu, Jian-Shuang

    2010-06-01

    Based on the meteorological data and remote sensing data, and by using vegetation-climate comprehensive model and CASA model, this paper analyzed the climate change trend and the spatiotemporal pattern of alpine grassland potential and actual net primary productivity (NPP) in Qiantang Plateau. In 1955-2004, the mean annual temperature and annual cumulated precipitation in the Plateau increased by 1.37 degrees C and 63 mm, respectively. The climate in the central and eastern parts of the Plateau became warmer and wetter, whereas it was warmer and dryer in the western part. However, the regional climate change did not yet result in grassland degradation. The mean potential NPP of alpine grassland was in the order of eastern part > central part > western part. From 1982 to 2004, the potential NPP in the central part had the largest increment (0.55 t x hm(-2) x a(-1)), followed by in the eastern part (0.51 t x hm(-2) x a(-1)) and western part (0.21 t x hm(-2) x a(-1)), which was consequent with the spatiotemporal pattern of climate change in the study area. In contrast, the actual NPP in the eastern, central, and western parts in the past two decades was -0.19, -0.03, and 0.20 t x hm(-2) x a(-1), respectively. Overgrazing was the main reason of grassland degradation in the central and eastern parts, and the central part was the key layout area for the implement of 'grazing withdrawal and management of grassland' project. PMID:20873612

  20. Uplift of the Colorado Plateau via Lower Crustal Foundering

    NASA Astrophysics Data System (ADS)

    Erdman, M.; Lee, C. T.; Jiang, H.

    2014-12-01

    How the Colorado Plateau reached its current elevation with little internal deformation compared to surrounding regions has perplexed researchers for nearly a century. Hypotheses to explain the two kilometers of uplift since the Late Cretaceous range from delamination of the Farallon plate following flat slab subduction, thermal expansion of upwelling mantle, dynamic topography in response to mantle upwelling, mid-crustal flow from over-thickened crust, and foundering of a dense lower crustal root. Many of these hypotheses are constrained by geodynamic modelling with limited evidence from the rock record. We report here the petrologic and geochemical makeup of lower crustal xenoliths from the Transition Zone in Arizona between the southern Basin and Range Province and the Colorado Plateau. This xenolith suite erupted within a ~25 Ma volcanic host and is dominated by garnet pyroxenite with minor gabbro and amphibolite. Major and trace element geochemistry, petrography, and thermobarometry suggest these rocks represent deep-seated (12-25 kb) cumulates formed during arc magmatism. A preliminary U-Pb sphene age of ~50 Ma suggests that the cumulates formed during the end of the Laramide orogeny. Calculated compositional densities for these cumulates are up to 10% greater than the mantle, suggesting that early to mid-Tertiary arc magmatism generated a dense and unstable lower crustal root. Because these rocks are cold (580-840 °C), thermal contraction may further increase the density contrast. Foundering of this dense root could cause significant uplift. Isostatic calculations show that two kilometers of uplift may be explained by removal of a 20-km-thick root that is 10% denser than the underlying mantle. If lower crustal foundering is indeed responsible for uplift of the Colorado Plateau, the eruption age of the xenolith suite constrains uplift to be younger than ~25 Ma.

  1. What's new in the management of complex tibial plateau fractures?

    PubMed

    Kokkalis, Zinon T; Iliopoulos, Ilias D; Pantazis, Constantinos; Panagiotopoulos, Elias

    2016-06-01

    The management of complex tibial plateau fractures is ever evolving. The severity of the injury to the surrounding soft tissues influences the timing and the method of fixation. Minimal invasive techniques continue to dominate our philosophy of reduction and reconstruction whereas augmentation of depressed intra-articular fragments remains an accepted strategy to maintain reduction and prevent secondary collapse. Locking plates, conventional plates and fine wire fixators all have been used successfully with satisfactory outcomes. In this article we report on the latest advances made in the management of these complex injuries. PMID:26989043

  2. Analytic formulas for above threshold ionization or detachment plateau spectra

    NASA Astrophysics Data System (ADS)

    Frolov, M. V.; Manakov, N. L.; Starace, Anthony F.

    2009-11-01

    Closed form analytic formulas are derived in the tunneling limit for both above threshold detachment (ATD) of negative ions and above threshold ionization (ATI) of neutral atoms. These formulas provide a fully quantum justification of the well-known classical three-step scenario for strong field ionization and detachment spectra in the high energy region of the ATI or ATD plateau and also provide analytical insight into how the ATI/ATD rates may be controlled by varying the laser field parameters or by varying the atomic species.

  3. Reconstructing plateau icefields: Evaluating empirical and modelled approaches

    NASA Astrophysics Data System (ADS)

    Pearce, Danni; Rea, Brice; Barr, Iestyn

    2013-04-01

    Glacial landforms are widely utilised to reconstruct former glacier geometries with a common aim to estimate the Equilibrium Line Altitudes (ELAs) and from these, infer palaeoclimatic conditions. Such inferences may be studied on a regional scale and used to correlate climatic gradients across large distances (e.g., Europe). In Britain, the traditional approach uses geomorphological mapping with hand contouring to derive the palaeo-ice surface. Recently, ice surface modelling enables an equilibrium profile reconstruction tuned using the geomorphology. Both methods permit derivation of palaeo-climate but no study has compared the two methods for the same ice-mass. This is important because either approach may result in differences in glacier limits, ELAs and palaeo-climate. This research uses both methods to reconstruct a plateau icefield and quantifies the results from a cartographic and geometrical aspect. Detailed geomorphological mapping of the Tweedsmuir Hills in the Southern Uplands, Scotland (c. 320 km2) was conducted to examine the extent of Younger Dryas (YD; 12.9 -11.7 cal. ka BP) glaciation. Landform evidence indicates a plateau icefield configuration of two separate ice-masses during the YD covering an area c. 45 km2 and 25 km2. The interpreted age is supported by new radiocarbon dating of basal stratigraphies and Terrestrial Cosmogenic Nuclide Analysis (TCNA) of in situ boulders. Both techniques produce similar configurations however; the model results in a coarser resolution requiring further processing if a cartographic map is required. When landforms are absent or fragmentary (e.g., trimlines and lateral moraines), like in many accumulation zones on plateau icefields, the geomorphological approach increasingly relies on extrapolation between lines of evidence and on the individual's perception of how the ice-mass ought to look. In some locations this results in an underestimation of the ice surface compared to the modelled surface most likely due to

  4. Audiomagnetotelluric data, Taos Plateau Volcanic Field, New Mexico

    USGS Publications Warehouse

    Ailes, Chad E.; Rodriguez, Brian D.

    2011-01-01

    The U.S. Geological Survey is conducting a series of multidisciplinary studies of the San Luis Basin as part of the Geologic framework of the Rio Grande Basins project. Detailed geologic mapping, high-resolution airborne magnetic surveys, gravity surveys, audiomagnetotelluric surveys, and hydrologic and lithologic data are being used to better understand the aquifers. This report describes a regional east-west audiomagnetotelluric sounding profile acquired in late July 2009 across the Taos Plateau Volcanic Field. No interpretation of the data is included.

  5. Influence of Andean Plateau Rise on South American Climate Dynamics

    NASA Astrophysics Data System (ADS)

    Insel, N.; Poulsen, C. J.; Ehlers, T. A.

    2008-12-01

    Large mountain ranges exhibit a first-order control on climate. In South America, the modern Andes act as a barrier to atmospheric flow and control regional wind and precipitation patterns. However, it is unclear how climate may have changed over time as Andean topography developed. We present results from a regional general circulation model (RegCM3) to evaluate dynamical and physical atmospheric changes associated with variations in Andean plateau height during the Cenozoic. A series of five experiments were conducted with plateau topography systematically varying between 0 and 100% of the modern. Experiments were performed over a continental-scale domain with 60km horizontal resolution using the MIT-Emanuel convection scheme. Land surface characteristics, sea-surface temperatures and atmospheric boundary conditions were specified from modern NCEP reanalysis data. Model results show that large-scale upper-level (200 mbar) circulation characteristics are only weakly affected by the removal of the Andes with a slight weakening and eastward shift of the high pressure system over Bolivia. However, low-level (800 mbar) wind patterns change significantly and have a direct effect on precipitation in South America. The following features can be observed as the Andean topography decreases: (1) The dominant wind direction in the central Andes reverses with prevailing winds sourced from the Pacific Ocean. The Westerlies are characterized by low moisture content due to the presence of the cold Humboldt current along the west coast of South America. (2) A reduction in the surface pressure gradient between the Andes and the Amazon Basin reduces convergence over the plateau and suppresses the South American low level jet, reducing the southward moisture flux along the eastern flanks of the Andes that is the primary source for precipitation in the Chaco region. These changes lead to declines in precipitation over the Andes and decreased latent heat release. This results in a

  6. Holocene aeolian sediments on the NE Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Stauch, G.; Lehmkuhl, F.; Hilgers, A.; Zhao, H.

    2012-04-01

    The semiarid climate of the northeastern Tibetan Plateau supports the formation of different types of aeolian sediments and landforms during the Holocene. Aeolians silts and sands in the catchment of the Donggi Cona in an elevation above 4000m to 4800 m asl reflect variable climate conditions during that time as well as different sediment sources. Based on 51 OSL datings and catchment wide geomorphological mapping a complex pattern of long and short distance sediment transport has been reconstructed. Only few aeolian archives are preserved from the late Pleistocene in this mountain environment indicating cold and dry climate conditions which prevented a continuous accumulation. During the early Holocene a phase of increased aeolian sedimentation of sand at the slopes of the mountains has been reconstructed. The sand originated from a large alluvial fan which was highly active during the Pleistocene. In addition, a thin loess cover is preserved at a few sites in the neighboring mountains ranges. The sedimentation of the loess started around 2000 years later than the sedimentation of the sand at the foot slope. Both archives are related to an increase in precipitation at the northern margin of the Tibetan Plateau which was related to a strengthening of the Asian Monsoon during that time. The wetter climate conditions favored the development of a vegetation cover which leads to the trapping and fixation of the aeolian sediments. However, with a further strengthening of the Monsoon systems these archives subsequently eroded due to higher run off and accumulated as colluvial and fluvial deposits in the basins. These phase lasted until 6 ka. A second aeolian period started at around 3 ka with the formation new dunes in the basins. This period can be associated with dry and cold climate of the late Holocene supporting the reactivation of the sand in the area. This might be further enhanced by an increased human impact by grazing during the late Holocene and resulting

  7. Outer planets exploration - A mission strategy for the 1980's

    NASA Technical Reports Server (NTRS)

    Moore, J. W.; Beckman, J. C.

    1977-01-01

    This paper presents a mission strategy for exploring the outer planets in the 1980s. The strategy is based on the anticipated findings of the 1977 Voyager Jupiter/Saturn Mission, and the 1982 Jupiter Orbiter Probe (JOP) Mission, recently approved as a new project start, beginning in October 1977. The JOP Mission then becomes a principal element in the strategy presented here. Characteristics (launch energy, trajectory parameters, etc.) of other mission opportunities to the outer planets in the 1980s are developed and presented. The need for and benefits from advanced propulsion systems, which can enable the more difficult missions to the outer planets, also are cited. The overall mission strategy, including a description of the options, is evolved in consideration of scientific rationale and return, and technical and programmatic coupling factors.

  8. Flexural ridges, trenches, and outer rises around coronae on Venus

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.; Schubert, Gerald

    1992-01-01

    Flexural signatures outboard of Venusian coronal rims are examined with the purpose of inferring the thickness of the planet's elastic lithosphere. Topographic profiles of several prominent coronae which display clear trench and outer rise signatures are presented. Via a thin elastic plate flexure model to characterize the shape of the trench and outer rise, Venusian flexures are found to be similar in both amplitude and wavelength to lithospheric flexures seaward of subduction zones on earth. It is shown that circumferential fractures are concentrated in areas where the topography is curved downward, in good agreement with the high tensile stress predicted by the flexure models. Two scenarios for the development of the ridge-trench-outer rise flexural topography and circumferential fractures of coronae are presented. The first scenario involves reheating and thermal subsidence of the lithosphere interior to the corona, while the second involves expansion of the corona interior and roll back of the subducting lithosphere exterior to the corona.

  9. Regimes for the ocean, outer space, and weather

    NASA Technical Reports Server (NTRS)

    Brown, S.; Cornell, N. W.; Fabian, L. L.; Weiss, E. B.

    1977-01-01

    The allocation of resources among users of the oceans, outer space and the weather is discussed. Attention is given to the international management of maritime navigation, the control of fisheries, offshore oil and gas exploitation, mineral exploitation in the deep seabed (especially the mining of manganese nodules), and the regulation of oceanographic studies. The management of outer space is considered, with special reference to remote sensing by satellites, television broadcasting, the technical requirements of maritime satellites, and problems associated with satellite frequency and orbit allocation. Rainmaking and typhoon modification, as well as the distribution of weather modification capabilities in the world, are also mentioned. The United Nations, international agencies and tribunals, and multi- or bilateral agreements are some of the implements suggested for use in the regulation of the oceans, outer space and the weather.

  10. Radio Wave Scattering in the Outer Heliosphere: Preliminary Calculations

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.

    1995-01-01

    Detailed first estimates are presented of angular broadening in the outer heliosphere due to scattering of radio waves by density irregularities. The application is to the 2-3 kHz radiation observed by Voyager. Two plausible turbulence models, which account very well for scattering within 1 AU, are extrapolated beyond 10 AU. Both models predict significant angular broadening in the outer heliosphere, accounting semi- quantitatively alone for the source sizes inferred from roll modulation data. Predictions are presented for radial variations in the apparent source size if scattering is important. Comparisons with available data argue that scattering is important (and indeed is the dominant contributor to the apparent source size) and that the radiation source is located in the outer heliosphere. Other evidence that scattering is important, such as the fluctuations in apparent source direction and intensity, are also identified. The effects of scattering should be included in future analyses of the 2-3 kHz emissions.

  11. Bacillus atrophaeus Outer Spore Coat Assembly and Ultrastructure

    SciTech Connect

    Plomp, M; Leighton, T J; Wheeler, K E; Pitesky, M E; Malkin, A J

    2005-11-21

    Our previous atomic force microscopy (AFM) studies successfully visualized native Bacillus atrophaeus spore coat ultrastructure and surface morphology. We have shown that the outer spore coat surface is formed by a crystalline array of {approx}11 nm thick rodlets, having a periodicity of {approx}8 nm. We present here further AFM ultrastructural investigations of air-dried and fully hydrated spore surface architecture. In the rodlet layer, planar and point defects, as well as domain boundaries, similar to those described for inorganic and macromolecular crystals, were identified. For several Bacillus species, rodlet structure assembly and architectural variation appear to be a consequence of species-specific nucleation and crystallization mechanisms that regulate the formation of the outer spore coat. We propose a unifying mechanism for nucleation and self-assembly of this crystalline layer on the outer spore coat surface.

  12. Substrate Specificity within a Family of Outer Membrane Carboxylate Channels

    SciTech Connect

    Eren, Elif; Vijayaraghavan, Jagamya; Liu, Jiaming; Cheneke, Belete R.; Touw, Debra S.; Lepore, Bryan W.; Indic, Mridhu; Movileanu, Liviu; van den Berg, Bert; Dutzler, Raimund

    2012-01-17

    Many Gram-negative bacteria, including human pathogens such as Pseudomonas aeruginosa, do not have large-channel porins. This results in an outer membrane (OM) that is highly impermeable to small polar molecules, making the bacteria intrinsically resistant towards many antibiotics. In such microorganisms, the majority of small molecules are taken up by members of the OprD outer membrane protein family. Here we show that OprD channels require a carboxyl group in the substrate for efficient transport, and based on this we have renamed the family Occ, for outer membrane carboxylate channels. We further show that Occ channels can be divided into two subfamilies, based on their very different substrate specificities. Our results rationalize how certain bacteria can efficiently take up a variety of substrates under nutrient-poor conditions without compromising membrane permeability. In addition, they explain how channel inactivation in response to antibiotics can cause resistance but does not lead to decreased fitness.

  13. The outer layers of cool, non-Mira carbon stars

    NASA Technical Reports Server (NTRS)

    Johnson, H. R.

    1991-01-01

    The outer layers and near circumstellar envelope (CSE) of a typical carbon star have been studied using available data from theoretical and empirical models. An attempt is made to match the density-velocity structure of the photosphere-chromosphere region to values from the radio CO observations, which arise from the outer CSE. It is concluded that the stellar atmosphere includes a relatively thin high-temperature region close to hydrostatic equilibrium and a much more extended cooler region of outflowing gas and dust. To extend the outer photosphere and chromosphere to match the mass loss density appears to require an injection of energy and momentum by some mechanism rather close to the stellar surface.

  14. A CCD comparison of outer Jovian satellites and Trojan asteroids

    NASA Technical Reports Server (NTRS)

    Luu, Jane X.

    1991-01-01

    The eight small outer Jovian satellites are not as well known as the brighter, more illustrious Galilean satellites. They are divided into two groups, each containing four satellites; the inner group travels in prograde orbits while the outer group travels in retrograde orbits. From the distinct orbital characteristics of the two groups, most of the theories of their origin involve the capture and breakup of two planetesimals upon entry into the atmosphere of proto-Jupiter. Their proximity to the Trojans asteroids has led to conjectures of a link between them and the Trojans. However, Tholen and Zellner (1984) found no red spectrum among six of the satellites and postulated that they were all C-type objects; therefore, they were unlikely to be derivatives of the Trojan population. Charge-coupled device (CCD) photometry and spectroscopy of the eight outer Jovian satellites obtained from 1987 to 1989 and a comparison between these eight satellites and the Trojan asteroids are presented.

  15. Alcohol-induced ciliary dysfunction targets the outer dynein arm

    PubMed Central

    Yang, Fan; Pavlik, Jacqueline; Fox, Laura; Scarbrough, Chasity; Sale, Winfield S.; Sisson, Joseph H.

    2015-01-01

    Alcohol abuse results in an increased incidence of pulmonary infection, in part attributable to impaired mucociliary clearance. Analysis of motility in mammalian airway cilia has revealed that alcohol impacts the ciliary dynein motors by a mechanism involving altered axonemal protein phosphorylation. Given the highly conserved nature of cilia, it is likely that the mechanisms for alcohol-induced ciliary dysfunction (AICD) are conserved. Thus we utilized the experimental advantages offered by the model organism, Chlamydomonas, to determine the precise effects of alcohol on ciliary dynein activity and identify axonemal phosphoproteins that are altered by alcohol exposure. Analysis of live cells or reactivated cell models showed that alcohol significantly inhibits ciliary motility in Chlamydomonas via a mechanism that is part of the axonemal structure. Taking advantage of informative mutant cells, we found that alcohol impacts the activity of the outer dynein arm. Consistent with this finding, alcohol exposure results in a significant reduction in ciliary beat frequency, a parameter of ciliary movement that requires normal outer dynein arm function. Using mutants that lack specific heavy-chain motor domains, we have determined that alcohol impacts the β- and γ-heavy chains of the outer dynein arm. Furthermore, using a phospho-threonine-specific antibody, we determined that the phosphorylation state of DCC1 of the outer dynein arm-docking complex is altered in the presence of alcohol, and its phosphorylation correlates with AICD. These results demonstrate that alcohol targets specific outer dynein arm components and suggest that DCC1 is part of an alcohol-sensitive mechanism that controls outer dynein arm activity. PMID:25595647

  16. Dynamic coupling among channel flow, plateau growth, foreland shortening, and the formation of metamorphic core complexes: Application to the Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Rey, P. F.; Teyssier, C.; Whitney, D. L.

    2009-04-01

    Gravitational potential energy stored in an orogenic plateau can be sufficiently strong to deform the surrounding region (foreland), hence contributing to both plateau growth and collapse. Gravity-driven channel flow from the plateau lower crust into the foreland lower crust, or channel extrusion, has been proposed as a main contributor to the eastward growth of the Tibetan plateau, possibly driving the lower crust channel as far as 1000 km beneath the foreland (eg. Royden et al., 2008). On the basis of numerical modeling using temperature-dependent viscosities and densities, we show that four processes impose severe limitations to channel extrusion: (1) cooling of the extruded channel, (2) convective motion in the plateau channel, (3) surface extension of the plateau, and (4) erosion of the plateau edge. Model results show that peak velocities in the extrusion channel drop rapidly (in less than a few My) from ca. 5 cm/year to less than 1 cm/year, owing to the rapid cooling in the channel from 750-850°C to 650-550°C as it travels into the foreland region. Channel flow extrusion is further slowed when convective flow initiates in the plateau channel as a result of only a few percent drop in density. This convection inhibits laminar flow in the channel, reduces the peak horizontal velocity in the channel to a few mm, and even drives a counter flow at the base of the channel, preventing its propagation toward the foreland. If the foreland is actively pulled away from the plateau (extending boundaries), the plateau upper crust undergoes extension and the lower crust moves up efficiently into a metamorphic core complex, which inhibits flow of the channel away from the plateau and even generates a counter flow from the foreland to the metamorphic core complex. If the foreland is fixed, the same phenomenon occurs as long as the foreland upper crust undergoes shortening (likely weakened by high pore fluid pressure), which enhances extension of the plateau and upward flow

  17. Study of Power Options for Jupiter and Outer Planet Missions

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Fincannon, James

    2015-01-01

    Power for missions to Jupiter and beyond presents a challenging goal for photovoltaic power systems, but NASA missions including Juno and the upcoming Europa Clipper mission have shown that it is possible to operate solar arrays at Jupiter. This work analyzes photovoltaic technologies for use in Jupiter and outer planet missions, including both conventional arrays, as well as analyzing the advantages of advanced solar cells, concentrator arrays, and thin film technologies. Index Terms - space exploration, spacecraft solar arrays, solar electric propulsion, photovoltaic cells, concentrator, Fresnel lens, Jupiter missions, outer planets.

  18. Photoprotective substance occurs primarily in outer layers of fish skin

    USGS Publications Warehouse

    Fabacher, D.L.; Little, E.E.

    1998-01-01

    Methanol extracts of dorsal skin layers, eyes, gills, and livers from ultraviolet-B (UVB) radiation-sensitive and UVB-tolerant species of freshwater fish were examined for a substance that appears to be photoprotective. Significantly larger amounts of this substance were found in extracts of outer dorsal skin layers from both UVB-sensitive and UVB-tolerant fish when compared with extracts of inner dorsal skin layers. This substance occurred in minor amounts or was not detected in eye, gill, and liver extracts. The apparent primary function of this substance in fish is to protect the cells in outer dorsal skin layers from harmful levels of UVB radiation.

  19. Seismic Waves within Earth's Outer Core: Multiple Reflection.

    PubMed

    Engdahl, E R

    1968-07-19

    Seismic waves reflected as many as four times within Earth's outer core are routinely recorded from large earthquakes. Observations of these waves are confined to rays near grazing incidence on the core-mantle boundary, in agreement with theoretical expectation. Minor adjustments to outer-core velocities may be necessary to account for certain of these arrivals that are not predicted by present core models. A change of 10 kilometers or more in the currently accepted core radius, 3473 kilometers, is not corroborated by the new data. PMID:17821162

  20. Outer insulation failure in a multilumen ICD lead.

    PubMed

    Wang, Yuxing; Zhou, Ying; Xu, Geng

    2013-08-01

    Insulation defects in the leads are a common complication in implantable cardioverter-defibrillators (ICDs). Although the new multilumen leads have significantly reduced the incidence of insulation defects, they have introduced the new and rare problem of outer-insulation abrasions. In this report, we present the case of a 53-year-old man with dilated cardiomyopathy who was found to have an outer-insulation abrasion on fluoroscopy 3 years after the implantation of an ICD. Several electrical storms experienced by the patient were considered to be responsible for the abrasions; results of routine evaluations were normal. A CRT-D device was finally implanted. PMID:24187774

  1. Soil carbon sequestration potential for "grain for green" project in Loess Plateau, China

    USGS Publications Warehouse

    Chang, R.; Fu, B.; Liu, Gaisheng; Liu, S.

    2011-01-01

    Conversion of cropland into perennial vegetation land can increase soil organic carbon (SOC) accumulation, which might be an important mitigation measure to sequester carbon dioxide from the atmosphere. The "Grain for Green" project, one of the most ambitious ecological programmes launched in modern China, aims at transforming the low-yield slope cropland into grassland and woodland. The Loess Plateau in China is the most important target of this project due to its serious soil erosion. The objectives of this study are to answer three questions: (1) what is the rate of the SOC accumulation for this "Grain for Green" project in Loess Plateau? (2) Is there a difference in SOC sequestration among different restoration types, including grassland, shrub and forest? (3) Is the effect of restoration types on SOC accumulation different among northern, middle and southern regions of the Loess Plateau? Based on analysis of the data collected from the literature conducted in the Loess Plateau, we found that SOC increased at a rate of 0.712 TgC/year in the top 20 cm soil layer for 60 years under this project across the entire Loess Plateau. This was a relatively reliable estimation based on current data, although there were some uncertainties. Compared to grassland, forest had a significantly greater effect on SOC accumulation in middle and southern Loess Plateau but had a weaker effect in the northern Loess Plateau. There were no differences found in SOC sequestration between shrub and grassland across the entire Loess Plateau. Grassland had a stronger effect on SOC sequestration in the northern Loess Plateau than in the middle and southern regions. In contrast, forest could increase more SOC in the middle and southern Loess Plateau than in the northern Loess Plateau, whereas shrub had a similar effect on SOC sequestration across the Loess Plateau. Our results suggest that the "Grain for Green" project can significantly increase the SOC storage in Loess Plateau, and it is

  2. PROPERTIES OF TYPE II PLATEAU SUPERNOVA SNLS-04D2dc: MULTICOLOR LIGHT CURVES OF SHOCK BREAKOUT AND PLATEAU

    SciTech Connect

    Tominaga, N.; Blinnikov, S.; Nomoto, K.; Baklanov, P.; Morokuma, T.; Suzuki, T. E-mail: tomoki.morokuma@nao.ac.j E-mail: baklanovp@gmail.co E-mail: suzuki@astron.s.u-tokyo.ac.j

    2009-11-01

    Shock breakout is the brightest radiative phenomenon in a Type II supernova (SN). Although it was predicted to be bright, direct observation is difficult due to the short duration and X-ray/ultraviolet-peaked spectra. First entire observations of the shock breakouts of Type II Plateau SNe (SNe IIP) were reported in 2008 by ultraviolet and optical observations by the Galaxy Evolution Explorer satellite and supernova legacy survey (SNLS), named SNLS-04D2dc and SNLS-06D1jd. We present multicolor light curves of an SN IIP, including the shock breakout and plateau, calculated with a multigroup radiation hydrodynamical code STELLA and an evolutionary progenitor model. The synthetic multicolor light curves reproduce well the observations of SNLS-04D2dc. This is the first study to reproduce the ultraviolet light curve of the shock breakout and the optical light curve of the plateau consistently. We conclude that SNLS-04D2dc is the explosion with a canonical explosion energy 1.2 x 10{sup 51} erg and that its progenitor is a star with a zero-age main-sequence mass 20 M{sub sun} and a presupernova radius 800 R{sub sun}. The model demonstrates that the peak apparent B-band magnitude of the shock breakout would be m {sub B} approx 26.4 mag if an SN identical to SNLS-04D2dc occurs at a redshift z = 1, which can be reached by 8m-class telescopes. The result evidences that the shock breakout has a great potential to detect SNe IIP at z approx> 1.

  3. Ice Core Recorded Climate changes on the Tibetan Plateau in the past 2000 years

    NASA Astrophysics Data System (ADS)

    Yao, T.; Yao Tandong

    2011-12-01

    Climate history on the Tibetan Plateau in the past 2000 years has been profusely studied using various proxies. Ice cores have been drilled on the Plateau since last century, with four cores systematically studied and widely reported as the Dasuopu (in Xixabangma on south Plateau), Guliya (in the west Kunlun Mt. on northwest Plateau), Puruogangri (in central Plateau), and Dunde (in Mt Qilian on north Plateau) ice cores. Different geographical locations of those four ice cores give rise to distinct climate histories, with the Dasuopu ice core representing variance of the Indian monsoon influence, the Guliya and Dunde ice cores representing that of the westerlies, and the Puruogangri ice core representing the interaction of both large-scale circulation systems. Despite different dominative circulation processes, study of modern delta-18O in precipitation suggests a positive correlation between delta-18O and temperature, thus confirming the representativeness of long-term delta-18O in ice cores of paleo-temperature. Each ice core record represents regional temperature variation, while comparison of those records highlight the synchronicity of significant climate events in the past 2000 years, including the Medieval Warm Period, Little Ice Age, and the 20th century warming. Besides, solar isolation is shown as the dominant factor over temperature changes on the Plateau, while variation of ENSO bears significantly on precipitation and snow accumulation on Tibetan glaciers. Recent studies of newly drilled ice cores in southeast Plateau reveals close relationship of temperature with bacteria variability, implying potential effect of global warming on bacteria activity. They also demonstrate significant effect of black carbon on glacial melting, suggesting increased influence of human activities on the southeast Plateau. With the widely distributed ice cores acquired, a composite of ice core records on the Plateau is in urgent need to demonstrate climate variation for the

  4. Independently dated paleomagnetic secular variation records from the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Haberzettl, Torsten; Henkel, Karoline; Kasper, Thomas; Ahlborn, Marieke; Su, Youliang; Wang, Junbo; Appel, Erwin; St-Onge, Guillaume; Stoner, Joseph; Daut, Gerhard; Zhu, Liping; Mäusbacher, Roland

    2015-04-01

    Magnetostratigraphy has been serving as a valuable tool for dating and confirming chronologies of lacustrine sediments in many parts of the world. Suitable paleomagnetic records on the Tibetan Plateau (TP) and adjacent areas are, however, extremely scarce. Here, we derive paleomagnetic records from independently radiocarbon-dated sediments from two lakes separated by 250 km on the southern central TP, Tangra Yumco and Taro Co. Studied through alternating field demagnetization of u-channel samples, characteristic remanent magnetization (ChRM) directions document similar inclination patterns in multiple sediment cores for the past 4000 years. Comparisons to an existing record from Nam Co, a lake 350 km east of Tangra Yumco, a varve-dated record from the Makran Accretionary Wedge, records from Lakes Issyk-Kul and Baikal, and a stack record from East Asia reveal many similarities in inclination. This regional similarity demonstrates the high potential of inclination to compare records over the Tibetan Plateau and eventually date other Tibetan records stratigraphically. PSV similarities over such a large area (>3000 km) suggest a large-scale core dynamic origin rather than small scale processes like drift of the non-dipole field often associated with PSV records.

  5. Increased mass over the Tibetan Plateau: From lakes or glaciers?

    NASA Astrophysics Data System (ADS)

    Zhang, Guoqing; Yao, Tandong; Xie, Hongjie; Kang, Shichang; Lei, Yanbin

    2013-05-01

    mass balance in the Inner Tibet Plateau (ITP) derived from the Gravity Recovery and Climate Experiment (GRACE) showed a positive rate that was attributed to the glacier mass gain, whereas glaciers in the region, from other field-based studies, showed an overall mass loss. In this study, we examine lake's water level and mass changes in the Tibetan Plateau (TP) and suggest that the increased mass measured by GRACE was predominately due to the increased water mass in lakes. For the 200 lakes in the TP with 4 to 7 years of ICESat data available, the mean lake level and total mass change rates were +0.14 m/yr and +4.95 Gt/yr, respectively. Compared those in the TP, 118 lakes in the ITP showed higher change rates (+0.20 m/yr and +4.28 Gt/yr), accounting for 59% area and 86% mass increase of the 200 lakes. The lake's mass increase rate in the ITP explains the 61% increased mass (~7 Gt/yr) derived from GRACE [Jacob et al., 2012], while it only accounts for 53% of the total lake area in the ITP.

  6. Tearing instabilities in the banana-plateau collisionality regime

    SciTech Connect

    Qu, W.X.; Callen, J.D.

    1985-04-01

    Starting from a resistive MHD set of equations and adding neoclassical currents (bootstrap, enhanced polarization and pinch type), we derive the eigenmode equation and relevant dispersion relation for ''neoclassical MHD'' tearing modes in the banana-plateau collisionality regime. The ballooning mode representation and a multiple length scale approximation are utilized. Analysis of the dispersion relation shows that the neoclassical effects on tearing modes are quite strong for ..sqrt..epsilon ..beta../sub p/(1 + nu/sub *//sub e/)/sup -1/ > S/sup -2/5/ (epsilon is the inverse aspect ratio, ..beta../sub p/ is the poloidal beta value, nu/sub *//sub e/ is the electron collisionality factor and S is the neoclassical MHD Reynolds number). The growth rate ..gamma.. and singular layer width deltax are increased typically by more than one order of magnitude from the usual values for epsilon ..beta../sub p/ approx. = 1. For our model, the changes in the tearing modes from the banana-plateau collisionality regime to the usual Pfirsch-Schlueter regime are very clear and natural.

  7. Old-field plant succession on the Pajarito Plateau

    SciTech Connect

    Foxx, T.; Mullen, M.; Salisbury, M.; Tierney, G.

    1997-10-01

    Eight fallow historic fields of the ponderosa pine and pinon-juniper cover types were surveyed to determine species composition and distribution. The purpose of the study was to understand plant succession on old fields as related to mechanically manipulated sites such as material disposal areas (MDAs). Additionally, the authors wanted a listing of species on disturbed lands of the Pajarito Plateau to aide in the reclamation planning of MDAs using native species. They also wanted to determine if any species could be used as an indicator of disturbance. The eight historic fields were all within Los Alamos County, New Mexico, and had been abandoned in 1943. Two sites were within the boundaries of Los Alamos National Laboratory and were studied both in 1982 and 1993. The study provides a description of each of the field sites, historic information about the homesteads from patent applications, a photographic record of some of the sites, and a listing of species found within each field. The study showed that there were 78 different plant species found on disturbed sites. Of these 78 species, 23 were found to be dominant on one or more of the MDAs or old fields. Although, the disturbance history of each site is imperfectly known, the study does provide an indication of successional processes within disturbed sites of the Pajarito Plateau. Additionally, it provides a listing of species that will invade disturbed sites, species that may be used in site reclamation.

  8. Satellite based estimates of soil moisture over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Su, Z.; Wang, L.; Dente, L.; van der Velde, R.; Wen, J.; Ofwono, M.

    2010-05-01

    Soil moisture plays essential role in water cycle and climate. In particular, over the Tibetan plateau, its importance is particularly pronounced in directly influencing the Monsoon systems and its precipitation patterns. The feasibility of retrieving top layer soil moisture from satellite data has been demonstrated and several techniques hold promise for extensive observation of soil moisture (Jackson et al., 1999; De Jeu and Owe, 2003; Njoku, 2004; Paloscia, et al., 2003; Su et al., 2003; Wagner et al., 2007; Wen et al., 2003; Wen and Su 2003). The consistency among the products derived using different algorithms and their uncertainties have not been yet documented. The launch of the SMOS satellite has, however, promoted renewed science interests in the production of consistent soil moisture products and use of these in water cycle and climate research (Kerr, 2007). This requires corresponding validation on the basis of extensive in-situ soil moisture measurements (Robock et al., 2000), before the consistency and uncertainties of such products can be quantified. We present recent progresses for better estimation of soil moisture at plateau and sub-continental scales by using available coarse active and passive microwave observations (SSM/I, WSC and ASCAT data in particular) and validation of the developed methodologies using in-situ measurements from dedicated SMOS cal/val sites. Preliminary validations for SMOS data will also be presented subject to data availability.

  9. Surface Deformation across Shillong Plateau and Bangladesh from GPS Data

    NASA Astrophysics Data System (ADS)

    Banerjee, P.; Walia, D.; Alam, A. K.; Ahsan, A.; Sharma, B.

    2014-12-01

    Interseismic strain accumulation arising out of India-Asia plate convergence process was found to be more pronounced in the eastern-most segment of the Himalaya. The 1897 Assam earthquake (M 8.7) , one of the great Himalayan earthquakes within last 500 years, is believed to have occurred over the south dipping boundary fault of the Shillong plateau. All along the Himalayan belt except in the eastern segment under study, the Main Frontal Thrust or equivalents at the immediate foothill of the Himalaya marks the southern edge of the locked segment, and region of high rate of surface strain accumulation is confined within a arc-parallel strip of around 200 km width. In the last 200 km long easternmost segment of the Himalaya, the southern boundary of the convergence related surface shortening seems to have been extended further south, much beyond the Himalayan frontal thrusts. This unusually wider deformation zone includes entire Shillong plateau in north-eastern part of India and extends into Bangladesh. New data from a recently established 16 station GPS network stretched over Bhutan, India and Bangladesh, in association with earlier data from the Indian network in this region provide better insight into this complex tectonic problem.

  10. Multielement stoichiometry of submerged macrophytes across Yunnan plateau lakes (China)

    PubMed Central

    Xing, Wei; Wu, Haoping; Shi, Qiao; Hao, Beibei; Liu, Han; Wang, Zhixiu; Liu, Guihua

    2015-01-01

    Stoichiometric homeostasis of element composition is one of the central concepts of ecological stoichiometry. We analyzed concentrations of macroelements (C, N, P, Ca, K, Mg, S), microelements (Cu, Fe, Mn, Mo, Ni, Zn) and beneficial elements (Na, Se, Si) in submerged macrophytes, water and sediments across 20 Yunnan plateau lakes. We predicted that tissue element composition in submerged macrophytes is affected by lake trophic level and taxonomy, and submerged macrophytes have weak stoichiometric homeostasis for all above 16 elements. Canonical discriminant analyses successfully discriminated among trophic level groups and taxa groups. Of all the elements, C, N, P and S most effectively discriminated among trophic level groups across 20 lakes, revealing lake trophic level mostly affect tissue macroelement composition in submerged macrophytes; while Ca, K and Se most effectively discriminated among submerged macrophytes taxa groups, suggesting taxonomy mostly affect compositions of macroelements and beneficial elements in submerged macrophytes. In addition, the stoichiometric homeostatic coefficient of 1/HCa:C for all five taxa of submerged macrophytes were less than zero, suggesting submerged macrophytes in Yunnan plateau lakes have strong Ca stoichiometric homeostasis. Our findings, not only broaden the knowledge of multielement stoichiometric homeostasis, but also help to choose most appropriate lake management strategy. PMID:25970822

  11. Tuberoplasty: minimally invasive osteosynthesis technique for tibial plateau fractures.

    PubMed

    Vendeuvre, T; Babusiaux, D; Brèque, C; Khiami, F; Steiger, V; Merienne, J-F; Scepi, M; Gayet, L E

    2013-06-01

    Fractures of the tibial plateau are in constant progression. They affect an elderly population suffering from a number of comorbidities, but also a young population increasingly practicing high-risk sports and using two-wheeled vehicles. The objective of this study was therefore to propose a new technique for the treatment of this type of fracture. There are a variety of classical pitfalls of conservative treatment such as defective reduction resulting in early osteoarthritis and alignment defects. Conventional treatments lead to joint stiffness and amyotrophy of the quadriceps, caused by the open technique and late loading. We propose an osteosynthesis technique for tibial plateau fractures with minimally invasive surgery. A minimally invasive technique would be more appropriate to remedy all of the surgical drawbacks resulting from current practices. The surgical technique that we propose uses a balloon allowing progressive and total reduction, associated with percutaneous screw fixation and filling with polymethylmethacrylate (PMMA) cement. The advantages are optimal reduction, minimal devascularization, soft tissues kept intact, as well as early loading and mobilization. This simple technique seems to be a good alternative to conventional treatment. The most comminuted fractures as well as the most posterior compressions can be treated, while causing the least impairment possible. Arthroscopy can be used to verify fracture reduction and cement leakage. At the same time, it can be used to assess the associated meniscal lesions and to repair them if necessary. PMID:23622864

  12. Wind-induced upwelling in the Kerguelen Plateau Region

    NASA Astrophysics Data System (ADS)

    Gille, S. T.; Carranza, M. M.; Cambra, R.; Morrow, R.

    2014-06-01

    In contrast to most of the Southern Ocean, the Kerguelen Plateau supports an unusually strong spring chlorophyll (Chl a) bloom, likely because the euphotic zone in the region is supplied with higher iron concentrations. This study uses satellite wind, sea surface temperature (SST), and ocean color data to explore the impact of wind-driven processes on upwelling of cold (presumably iron-rich) water to the euphotic zone. High wind speeds typically correlate with cold sea surface temperatures, implying that wind-mixing leads to enhanced vertical mixing. Negative wind-stress curl also correlates with cold SSTs, implying that Ekman pumping can further enhance upwelling, and coupling between winds and SSTs associated with mesoscale eddies can locally modulate the wind-stress curl. Kerguelen has a significant wind shadow on its downwind side, which generates a wind-stress curl dipole that shifts location depending on wind direction. This leads to locally enhanced Ekman pumping on the downstream side of the Kerguelen Plateau, where Chl a blooms are observed most years.

  13. Surgical Technique of Anterolateral Approach for Tibial Plateau Fracture.

    PubMed

    Wang, Peng-cheng; Ren, Dong; Zhou, Bing

    2015-11-01

    A 66-year-old woman had sustained crush injury 3 hours prior to her presentation to our hospital. The diagnosis was defined as lateral tibial plateau fracture of the right knee (Schatzker III). Supine position was set up and a pad was put under the affected hip. After sterilization of the surgical field the sterilized sheets were placed beneath the leg in order to be higher than the other side. A rolled sheet was put under the knee joint so that the knee joint was flexed around 30° to 40°. After the surgical field was draped the skin was incised. Iliotibial band was incised by blade (not by electrotomy) and sharp dissection was performed in the Gerdy's tubercle. Capsulotomy was made by cutting the tibial meniscal ligament. Then the meniscus was tagged superiorly and the articular surface was clearly visualized. A window was made in the lateral cortex beneath the plateau, so the impacted fragment was elevated through the window. The metaphyseal void was filled by bone allograft. The placement of the raft-screw plate must be ensured that the raft screws passing the plate could purchase the subchondral bone. After perfect placement of the plate was defined, the femoral distractor was removed and the knee joint was relaxed. It was ensured that the alignment of the lower leg was normal, and then the other screws were inserted. Following placing drainage in the wound the iliotibial band was closed and the subcutaneous soft tissue and skin were closed in layer. PMID:26791810

  14. Active Submarine Hotspot Volcanism on the Kerguelen Plateau

    NASA Astrophysics Data System (ADS)

    Coffin, M. F.; Leser, T. E.

    2012-12-01

    Heard and McDonald Islands on the Kerguelen Plateau, southern Indian Ocean, are active intraplate hotspot volcanoes. Heard Island is approximately 43 km long, and encompasses an area of approximately 368 square km. It is dominated by Big Ben, a roughly circular volcano with a base diameter of 18-20 km, and a maximum elevation of 2745 m. The McDonald Islands have an area of approximately 2.5 square km. Due to a lack of human habitation and no geoscientific monitoring, and cloud cover precluding satellite remote sensing for geoscientific purposes, the level of volcanic activity of the islands is unknown, but observers on passing ships frequently report eruptions, including molten lava, volcanic plumes, and tephra, and active fumaroles. Bathymetric, seismic reflection, magnetic, and gravity data acquired around Heard and McDonald Islands suggest that submarine magmatism affects a broad region of surrounding Kerguelen Plateau seafloor. In this region, we have identified six distinct fields of sea knolls that we interpret to be volcanic in origin. Individual fields contain from approximately 14 to approximately 140 sea knolls, and are not uniformly distributed around Heard and McDonald Islands. Given that Heard and McDonald Islands are volcanically active, it is likely that at least some of the interpreted submarine volcanoes are active and drive hydrothermal circulation.

  15. Geomorphology and hydrogeology of the Edwards Plateau karst, central Texas

    NASA Astrophysics Data System (ADS)

    Kastning, E. H., Jr.

    The Edwards Plateau is one of the largest continuous karst regions of the United States; yet, its geomorphic evolution has previously received little systematic study. The overall objectives of this investigation are to: (1) describe the physical characteristics of karst features, (2) determine which geomorphic and hydrogeologic controls and processes have governed their development, and (3) relate genesis of karst spatially and chronologically to the geomorphic evolution of the Edwards Plateau. Cavern development provides a record of evolution of karst and the development of major carbonate aquifers of the region. Some control on cavern development are region-wide; nevertheless, many caves exhibit characteristics that suggest a strong influence of local factors. Development of cave chambers and passages has responded to the lithic character of bedrocks. Solution conduits were guided by variations in calcite and dolomite content, thickness of strata, and frequency of bedding-plane partings. This is particularly true of the Glen Rose Formation, limestone beds of the Edwards Group, and the Gorman Formation, the three principal cave-forming units.

  16. Tertiary Magmatism on the Early Cretaceous Ontong Java Plateau

    NASA Astrophysics Data System (ADS)

    Coffin, M. F.; Inoue, H.; Mochizuki, K.; Nakamura, Y.; Kroenke, L.

    2008-12-01

    The Ontong Java Plateau (OJP) in the western equatorial Pacific is the largest flood basalt province, or large igneous province (LIP), known in the oceans. Although the bulk of the OJP is believed to have formed in Early Cretaceous time, ca. 122 Ma, ca, 90 Ma basalts have also been recovered from the OJP and obducted OJP sections in the Solomon Islands. Still younger igneous rock is found in the Solomon Islands (Tejada et al., 1996), and the submarine plateau is itself surmounted by atolls, seamounts, and other features of presumed igneous origin, for which age data are lacking. To investigate this apparently younger igneous activity on the OJP itself, we have identified submarine lava flows and/or a volcaniclastic apron around Tauu Atoll on the southwestern OJP using seismic reflection data. Through stratigraphic correlation with Deep Sea Drilling Project and Ocean Drilling Program sites, we interpret the age of the igneous activity that created Tauu Atoll to be Middle Eocene to Miocene. Through similar seismic identification and stratigraphic correlation, we interpret an Oligocene to Miocene age for three hydrothermal vents in the central OJP. On the northwestern margin of the OJP, an unnamed seamount likely represents impingement of the much younger Caroline hotspot with the OJP. More seismic reflection and/or drilling data will be required to date Ontong Java Atoll, one of the largest atolls on the globe, as well as the many other atolls and seamounts surmounting the OJP.

  17. Snow Surface Microbiome on the High Antarctic Plateau (DOME C)

    PubMed Central

    Michaud, Luigi; Lo Giudice, Angelina; Mysara, Mohamed; Monsieurs, Pieter; Raffa, Carmela; Leys, Natalie; Amalfitano, Stefano; Van Houdt, Rob

    2014-01-01

    The cryosphere is an integral part of the global climate system and one of the major habitable ecosystems of Earth's biosphere. These permanently frozen environments harbor diverse, viable and metabolically active microbial populations that represent almost all the major phylogenetic groups. In this study, we investigated the microbial diversity in the surface snow surrounding the Concordia Research Station on the High Antarctic Plateau through a polyphasic approach, including direct prokaryotic quantification by flow cytometry and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH), and phylogenetic identification by 16S RNA gene clone library sequencing and 454 16S amplicon pyrosequencing. Although the microbial abundance was low (<103 cells/ml of snowmelt), concordant results were obtained with the different techniques. The microbial community was mainly composed of members of the Alpha-proteobacteria class (e.g. Kiloniellaceae and Rhodobacteraceae), which is one of the most well-represented bacterial groups in marine habitats, Bacteroidetes (e.g. Cryomorphaceae and Flavobacteriaceae) and Cyanobacteria. Based on our results, polar microorganisms could not only be considered as deposited airborne particles, but as an active component of the snowpack ecology of the High Antarctic Plateau. PMID:25101779

  18. Climate modulation of the Tibetan Plateau on haze in China

    NASA Astrophysics Data System (ADS)

    Xu, X.; Zhao, T.; Liu, F.; Gong, S. L.; Kristovich, D.; Lu, C.; Guo, Y.; Cheng, X.; Wang, Y.; Ding, G.

    2016-02-01

    Rapid increases in pollutant emissions in conjunction with stagnant meteorological conditions result in haze pollution in China. Recent frequent haze in China has attracted worldwide attention. Here we show a relationship between the haze events and Tibetan Plateau (TP)'s environment and climate changes. Based on observational data taken over recent decades, we identify central-eastern China (CEC) as a climatological large-scale "susceptible region" of frequent haze, which is harbored by the TP with its impact on midlatitude westerly winds. The observational and modeling studies demonstrate that the interannual variations in the thermal forcing of TP are positively correlated with the incidences of wintertime haze over CEC. Further analysis indicates that the climate warming of the TP induced changes in atmospheric circulation, driving frequent haze events in CEC. The frequent haze occurrences in CEC are consistent with decreasing winter monsoon winds, intensifying downward air flows and increasing atmospheric stability in the lower troposphere over the CEC in association with upstream plateau's thermal anomalies. Therefore, variations of haze in China are related to mechanical and thermal forcing by the TP. Our results also suggest that implications of the large TP topography for environment and climate changes should be taken into account for air pollution mitigation policies in China.

  19. The Rheological Structure of the East Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Jiang, X.; Jin, Y.

    2012-04-01

    The Rheological Structure of the East Tibetan Plateau Xiaodian Jiang1, and Yu Jin2 1. Ocean University of China, Qingdao 266003, China 2. Chevron Exploration & Production, Beijing 100004, China The rheological structure of the lithosphere can be calibrated with seismic activities. We intensively use the seismic focal depths from 2072 events occurring in Longmenshan Fold Belt (LFB) area to identify the transition from brittle failure to ductile with depth in the lithosphere. The earthquakes were monitored by China Earthquake Network Center (CENC) from 01/07/1970 through 31/08/2010 with magnitude larger than 3.5 at 88 earthquake stations with a depth error bar of ±2km. Among the 2072 seismic events, 82 of them have a magnitude larger than 5 and were recorded simultaneously by the NEIC and CENC since January 1, 1990. The parameters of the 82 events recorded by both institutions are in close agreement. Most of the earthquakes in LFB and its vicinity occurred at depths from 2 to 36 km. However, there are 3 extras with focal depth at 39, 44 and 60 km respectively. All these three events occurred in Sichuan Basin where the lithosphere is not decouple between the crust and the upper mantle so that the brittle failure is able to propagate all the way from the crust to the upper mantle lithosphere. Because all of the seismic events in the eastern Tibetan plateau occurred at the depths less than or equal to 36±2 km deep, the 36±2 km should be a good statistical number to define the lower boundary of the elastically strong, brittle upper/middle crust. The Moho depth across LFB calculated by the 3D flexural modeling in space domain constrained by the gridded gravity database and merged our new measurement data varies considerably from about 38 km in Sichuan Basin to about 58 km beneath the eastern plateau. The Moho depths in the eastern plateau are in lower to mid 50 km deep. In the other words, the thermally depending ductile, weak lower crust is rheologically defined the

  20. Outer Continental Shelf Environmental Assessment Program: comprehensive bibliography, January 1988

    SciTech Connect

    Not Available

    1988-01-01

    The bibliography lists reports from investigators of the Alaska Outer Continental Shelf Environmental Assessment Program. Some non-program documents are also included. More than 3600 entries are sorted by author and citation number. Cross-references are available by Alaska region, discipline and research unit number.

  1. Disulfide-bonded outer membrane proteins in the genus Legionella.

    PubMed Central

    Butler, C A; Street, E D; Hatch, T P; Hoffman, P S

    1985-01-01

    Legionella pneumophila and related species were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for outer membrane proteins. Of the 10 species examined, 9 contained a 24-kilodalton (kDa) major outer membrane protein (MOMP) that was resolvable only when outer membrane material was heated in the presence of 2-mercaptoethanol. Labeling studies with [35S]cysteine indicated that the protein contained cysteine, and disulfide cross-linking of the unreduced complex was demonstrated by labeling with iodoacetamide. The unreduced outer membrane preparation contained peptidoglycan, and after treatment with lysozyme to remove peptidoglycan, a protein complex of 95 kDa was observed by sodium dodecyl sulfate polyacrylamide gel electrophoresis in the absence of 2-mercaptoethanol. Reduction of the 95-kDa complex yielded 24-kDa monomers, suggesting that the 95-kDa complex was composed of four subunits. The 24-kDa MOMP from L. pneumophila was purified, and antibody produced to this protein cross-reacted with all species of Legionella as determined from an immunoblot of a sodium dodecyl sulfate gel. Only serogroup 1 strains of L. bozemanii lacked the 24-kDa MOMP and showed no cross-reactivity. These results suggest that the 24-kDa MOMP common to most species of Legionella contains a genus-specific epitope. Images PMID:3980079

  2. Identification of Pasteurella multocida CHAPS-soluble outer membrane proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fowl cholera continues to be of concern to the poultry industry, especially for turkey growers. This disease costs the turkey industry millions of dollars annually. In order to gain a better understanding of Pasteurella multocida virulence factors involved in colonization and pathogenesis, the outer...

  3. Protection of celestial environments and the law of outer space

    NASA Astrophysics Data System (ADS)

    Tennen, Leslie; Race, Margaret

    The law of outer space expressly addresses the matter of preservation and protection of natural celestial environments from harmful contamination and disruption by mankind in the explo-ration and use of outer space, including the moon and other celestial bodies. The Outer Space Treaty, however, does not prohibit all human impact to an extraterrestrial environment, but rather permits a wide range of activities that could have significant environmental ramifications. This legal regime may be in conflict with the interests of preserving celestial environments for scientific research, especially when considered in relation to activities conducted for commercial purposes. Nevertheless, the Moon Agreement provides a mechanism by which special protective measures can be implemented to protect particular areas of the moon and other celestial bodies for scientific investigation. This paper examines the current status of the law of outer space vis-a-vis the protection and preservation of natural celestial environments. Particular emphasis is placed on the policies on which the legal obligations are based, together with consideration of the non-appropriation principle, and the commercial use of lunar and other celestial resources and areas. In addition, the concepts of international scientific preserves, special regions, keep out zones, and planetary parks are compared and evaluated as potential means to limit the disturbance to celestial environments caused by the activities of mankind.

  4. VIEW OF THE OUTER RING OF CENTER CIRCLE, LOOKING NORTH. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF THE OUTER RING OF CENTER CIRCLE, LOOKING NORTH. GRANITE COPING DEFINES THE SWAIN FAMILY PLOT, WHICH CONTAINS A CELTIC CROSS, ON WHICH THE CIRCLE REFERS TO ETERNAL LIFE, AND A RECLINING HUMAN FIGURE IN ETERNAL SLEEP - Woodlands Cemetery, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  5. Nodulation outer proteins: double-edged swords of symbiotic rhizobia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation is the result of a complex bacterial infection process, which depends on signals and surface determinants produced by both symbiotic partners. Among them, rhizobial nodulation outer proteins (Nops)...

  6. Outer-Sphere Direction in Iridium C-H Borylation

    PubMed Central

    Roosen, Philipp C.; Kallepalli, Venkata A.; Chattopadhyay, Buddhadeb; Singleton, Daniel A.; Maleczka, Robert E.; Smith, Milton R.

    2013-01-01

    The NHBoc group affords ortho selective C–H borylations in arenes and alkenes. Experimental and computational studies support an outer sphere mechanism where the N–H proton hydrogen bonds to a boryl ligand oxygen. The regioselectivities are unique and complement those of directed ortho metalations. PMID:22703452

  7. Wettability on Inner and Outer Surface of Single Carbon Nanotubes.

    PubMed

    Yamada, Yutaka; Takahashi, Koji; Takata, Yasuyuki; Sefiane, Khellil

    2016-07-19

    The surface wettability of a liquid on the inner and outer surface of single carbon nanotubes (CNTs) was experimentally investigated. Although these contact angles on both surfaces were previously studied separately, the available data are of limited help to elucidate the effect of curvature orientation (concave or convex) on wettability due to the difference in surface structure. Here, we report on the three-phase contact region and wettability on the outer surface of CNT during the dipping and withdrawing experiment of CNT into an ionic liquid. Furthermore, the wettability on the inner surface was measured using a liquid within the same CNT. Our results show that the contact angle on the outer surface of the CNT is larger than that on the flat surface and that on the inner surface is smaller than that on the flat one. These findings suggest that the surface curvature orientation has a noticeable effect on the contact angle at the nanoscale because both inner and outer surfaces expose the same graphite wall structure and the contact line tension will be negligible in this situation. The presented results are rationalized using the free energy balance of liquid on curved surfaces. PMID:27351126

  8. Virulent strain associated outer membrane proteins of Borrelia burgdorferi.

    PubMed Central

    Skare, J T; Shang, E S; Foley, D M; Blanco, D R; Champion, C I; Mirzabekov, T; Sokolov, Y; Kagan, B L; Miller, J N; Lovett, M A

    1995-01-01

    We have isolated and purified outer membrane vesicles (OMV) from Borrelia burgdorferi strain B31 based on methods developed for isolation of Treponema pallidum OMV. Purified OMV exhibited distinct porin activities with conductances of 0.6 and 12.6 nano-Siemen and had no detectable beta-NADH oxidase activity indicating their outer membrane origin and their lack of inner membrane contamination, respectively. Hydrophobic proteins were identified by phase partitioning with Triton X-114. Most of these hydrophobic membrane proteins were not acylated, suggesting that they are outer membrane-spanning proteins. Identification of palmitate-labeled lipoproteins revealed that several were enriched in the OMV, several were enriched in the protoplasmic cylinder inner membrane fraction, and others were found exclusively associated with the inner membrane. The protein composition of OMV changed significantly with successive in vitro cultivation of strain B31. Using antiserum with specificity for virulent strain B31, we identified OMV antigens on the surface of the spirochete and identified proteins whose presence in OMV could be correlated with virulence and protective immunity in the rabbit Lyme disease model. These virulent strain associated outer membrane-spanning proteins may provide new insight into the pathogenesis of Lyme disease. Images PMID:7593626

  9. Outer planet probe navigation. [considering Pioneer space missions

    NASA Technical Reports Server (NTRS)

    Friedman, L.

    1974-01-01

    A series of navigation studies in conjunction with outer planet Pioneer missions are reformed to determine navigation requirements and measurement systems in order to target probes. Some particular cases are established where optical navigation is important and some cases where radio alone navigation is suffucient. Considered are a direct Saturn mission, a Saturn Uranus mission, a Jupiter Uranus mission, and a Titan probe mission.

  10. Outer Space: A Multi-Age, Integrated Subjects Curriculum Unit.

    ERIC Educational Resources Information Center

    Hall, William D.

    This multi-age integrated teaching unit on outer space was developed by 19 rural teachers (grades K-8) from 12 Gallatin County (Montana) districts to associate all school subjects with a common theme, promote teaching efficiency by focusing on more than one subject at the same time, and increase student excitement. Topics explored by each grade…

  11. Advanced space storable propellants for outer planet exploration

    NASA Technical Reports Server (NTRS)

    Thunnissen, Daniel P.; Guernsey, Carl S.; Baker, Raymond S.; Miyake, Robert N.

    2004-01-01

    An evaluation of the feasibility and mission performance benefits of using advanced space storable propellants for outer planet exploration was performed. For the purpose of this study, space storable propellants are defined to be propellants which can be passively stored without the need for active cooling.

  12. Applications Of Graphite Fluoride Fibers In Outer Space

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheng; Long, Martin; Dever, Therese

    1993-01-01

    Report characterizes graphite fluoride fibers made from commercially available graphitized carbon fibers and discusses some potential applications of graphite fluoride fibers in outer space. Applications include heat-sinking printed-circuit boards, solar concentrators, and absorption of radar waves. Other applications based on exploitation of increased resistance to degradation by atomic oxygen, present in low orbits around Earth.

  13. Molecular Basis of Bacterial Outer Membrane Permeability Revisited

    PubMed Central

    Nikaido, Hiroshi

    2003-01-01

    Gram-negative bacteria characteristically are surrounded by an additional membrane layer, the outer membrane. Although outer membrane components often play important roles in the interaction of symbiotic or pathogenic bacteria with their host organisms, the major role of this membrane must usually be to serve as a permeability barrier to prevent the entry of noxious compounds and at the same time to allow the influx of nutrient molecules. This review summarizes the development in the field since our previous review (H. Nikaido and M. Vaara, Microbiol. Rev. 49:1-32, 1985) was published. With the discovery of protein channels, structural knowledge enables us to understand in molecular detail how porins, specific channels, TonB-linked receptors, and other proteins function. We are now beginning to see how the export of large proteins occurs across the outer membrane. With our knowledge of the lipopolysaccharide-phospholipid asymmetric bilayer of the outer membrane, we are finally beginning to understand how this bilayer can retard the entry of lipophilic compounds, owing to our increasing knowledge about the chemistry of lipopolysaccharide from diverse organisms and the way in which lipopolysaccharide structure is modified by environmental conditions. PMID:14665678

  14. Lunar and Planetary Science XXXV: Outer Solar System

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Outer Solar System" included the following reports:New Data About Seasonal Variations of the North-South Asymmetry of Polarized Light of Jupiter; Appearance of Second Harmonic in the Jupiter Spectrum; Dynamics of Confined Liquid Mass, Spreading on Planet Surface; "Cassini" will Discover 116 New Satellites of Saturn!; Jupiter's Light Reflection Law;and Internal Structure Modelling of Europa.

  15. 9 CFR 108.10 - Outer premises and stables.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Outer premises and stables. 108.10 Section 108.10 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS FACILITY REQUIREMENTS...

  16. 3-D orbital evolution model of outer asteroid belt

    NASA Technical Reports Server (NTRS)

    Solovaya, Nina A.; Gerasimov, Igor A.; Pittich, Eduard M.

    1992-01-01

    The evolution of minor planets in the outer part of the asteroid belt is considered. In the framework of the semi-averaged elliptic restricted three-dimensional three-body model, the boundary of regions of the Hill's stability is found. As was shown in our work, the Jacobian integral exists.

  17. The January 13, 2007, Kuril Islands Outer Rise Earthquake

    NASA Astrophysics Data System (ADS)

    Polet, J.; Thio, H. K.

    2007-12-01

    We will present the results of an investigation of the January 13, 2007, Kuril Islands Mw=8.1 normal faulting outer rise earthquake that occurred in close proximity of an Mw=8.3 interplate event that took place two months earlier. Our primary interest is in determining the depth extent of its rupture process through the modeling of seismic waveforms and tsunami data. This earthquake was one of the greatest outer rise earthquakes of the past century and is certainly the best recorded. We will put this event in the context of a larger framework of worldwide outer rise earthquake occurrence in the past 35 years, using a catalog that we created by applying a search algorithm, based on earthquake mechanism in combination with local subduction zone geometry, to the Global CMT catalog. The January 13 earthquake was followed by a unproductive aftershock sequence and preceded by a significant number of events in the outer rise area following the Mw=8.3 interplate event of December 2006. We will also show the results of a basic analysis of the temporal and spatial characteristics of both of these sequences.

  18. 9 CFR 108.10 - Outer premises and stables.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Outer premises and stables. 108.10 Section 108.10 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS FACILITY REQUIREMENTS...

  19. Aerocapture Technology Development Needs for Outer Planet Exploration

    NASA Technical Reports Server (NTRS)

    Wercinski, Paul; Munk, Michelle; Powell, Richard; Hall, Jeff; Graves, Claude; Partridge, Harry (Technical Monitor)

    2002-01-01

    The purpose of this white paper is to identify aerocapture technology and system level development needs to enable NASA future mission planning to support Outer Planet Exploration. Aerocapture is a flight maneuver that takes place at very high speeds within a planet's atmosphere that provides a change in velocity using aerodynamic forces (in contrast to propulsive thrust) for orbit insertion. Aerocapture is very much a system level technology where individual disciplines such as system analysis and integrated vehicle design, aerodynamics, aerothermal environments, thermal protection systems (TPS), guidance, navigation and control (GN&C) instrumentation need to be integrated and optimized to meet mission specific requirements. This paper identifies on-going activities, their relevance and potential benefit to outer planet aerocapture that include New Millennium ST7 Aerocapture concept definition study, Mars Exploration Program aeroassist project level support, and FY01 Aeroassist In-Space Guideline tasks. The challenges of performing aerocapture for outer planet missions such as Titan Explorer or Neptune Orbiter require investments to advance the technology readiness of the aerocapture technology disciplines for the unique application of outer planet aerocapture. This white paper will identify critical technology gaps (with emphasis on aeroshell concepts) and strategies for advancement.

  20. 9 CFR 108.10 - Outer premises and stables.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Outer premises and stables. 108.10 Section 108.10 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS FACILITY REQUIREMENTS FOR LICENSED ESTABLISHMENTS § 108.10...

  1. 9 CFR 108.10 - Outer premises and stables.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Outer premises and stables. 108.10 Section 108.10 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS FACILITY REQUIREMENTS FOR LICENSED ESTABLISHMENTS § 108.10...

  2. 9 CFR 108.10 - Outer premises and stables.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Outer premises and stables. 108.10 Section 108.10 Animals and Animal Products ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS FACILITY REQUIREMENTS FOR LICENSED ESTABLISHMENTS § 108.10...

  3. Repeatable and Predictable Dynamics of the Outer Radiation Belt

    NASA Astrophysics Data System (ADS)

    Murphy, K. R.; Mann, I. R.; Sibeck, D. G.; Ozeke, L.; Rae, J.; Watt, C.

    2015-12-01

    Many believe that the response of energetic electrons in the outer radiation belt to each geomagnetic storm is unique, such that the response to any two storms in never the same. This has coined the popular phrase "If you've seen one storm, you've seen one storm". Here we investigate the response of energetic electrons in the outer radiation belt to geomagnetic storms driven by Coronal Mass Ejections (CMEs) and Co-rotating Interaction Regions (CIRs) during the SAMPEX era through solar cycle 23 (1994-2004). We demonstrate that the outer radiation belt responds consistently and predictably to external solar wind energy input and magnetospheric wave dynamics such that larger geomagnetic storms are associated with both increased loss and acceleration. In particular, we demonstrate that the amount of electron loss in the outer radiation belt and subsequent acceleration during a geomagnetic storms is very well characterised by the total energy input from the solar wind, the minimum location of the magnetopause, minimum Dst, and ULF wave power within the inner magnetosphere. Finally we demonstrate that CMEs and CIRs have different external and internal driving conditions that produce distinct belt morphologies. However, a simple ULF wave diffusion model can reproduce both morphologies. This demonstrates how the radiation belts respond predictably for different storm drivers and magnetospheric dynamics.

  4. Ethane Ices in the Outer Solar System: Spectroscopy and Chemistry

    NASA Technical Reports Server (NTRS)

    Hudson, R. L.; Moore, M. H.; Raines, L. L.

    2009-01-01

    We report recent experiments on ethane ices made at temperatures applicable to the outer Solar System. New near- and mid-infrared data for crystalline and amorphous ethane, including new spectra for a seldom-studied solid phase that exists at 35-55 K, are presented along with radiation-chemical experiments showing the formation of more-complex hydrocarbons,

  5. Map showing structural control of breccia pipes on the southern Marble Plateau, north-central Arizona

    SciTech Connect

    Sutphin, H.B.; Wenrich, K.J.

    1988-01-01

    Solution collapse breccia pipes, concentrated throughout the southwestern corner of the Colorado Plateau in Arizona, have been mapped in detail on the southern Marble Plateau. Within the study area, 77 of the 90 (86%) collapse structures fall within northwest-trending and northeast-trending zones that cover only 23% of the total surface area.

  6. 77 FR 1717 - Notice of Availability; Draft Springfield Plateau Regional Restoration Plan and Environmental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... Fish and Wildlife Service Notice of Availability; Draft Springfield Plateau Regional Restoration Plan... Department of Natural Resources, have written a Draft Springfield Plateau Regional Restoration Plan and...) are trustees for natural resources considered in this restoration plan, pursuant to subpart G of...

  7. Take Me to Your Ladder: The Issue of Plateauing in Children's Services Positions.

    ERIC Educational Resources Information Center

    Feehan, Patricia

    1994-01-01

    Discusses the background and reasons for career plateauing in children's services librarianship in public libraries. The profession's philosophy, the skills children's librarians develop, reasons why children's librarians do not often become upper-level administrators, and ways to maintain creativity when jobs become plateaued are covered. (13…

  8. Effect of Handling, Storage and Cycling on Ni-H2 Cells: Second Plateau Phenomenon

    NASA Technical Reports Server (NTRS)

    Vaidyanathan, Hari; Rao, Gopalakrishna M.; Day, John H. (Technical Monitor)

    2000-01-01

    A viewgraph presentation outlines the effects of handling, storing, and cycling of NiH2 cells, particularly the second plateau phenomenon. Details are given on the criteria for cell selection, cell history, the second plateau capacity at C/2 discharge, and cell reversal test conditions. Tables display a gas analysis and nickel precharge.

  9. A new species of Mongolodectes (Orthoptera: Tettigoniidae) from Alashan Plateau in China.

    PubMed

    Liu, Chun-Xiang; Xu, Wen-Jing; Zhang, Chun-Tian

    2015-01-01

    The genus Mongolodectes is endemic to vast Mongolian Plateau and has two recorded species in the Mongolian People's Republic and one species in China's Inner Mongolia. Here we describe one new species Mongolodectes huangi sp. n. from China's Inner Mongolia. Further investigations are needed for precise identification and complete understanding on the fauna of the Mongolian Plateau. PMID:26701430

  10. The Amsterdam-St. Paul Plateau: A complex hot spot/DUPAL-flavored MORB interaction

    NASA Astrophysics Data System (ADS)

    Janin, M.; HéMond, C.; Maia, M.; Nonnotte, P.; Ponzevera, E.; Johnson, K. T. M.

    2012-09-01

    The Amsterdam-St Paul (ASP) oceanic plateau results from the interaction between the ASP hot spot and the Southeast Indian ridge. A volcanic chain, named the Chain of the Dead Poets (CDP), lies to its northward tip and is related to the hot spot intraplate activity. The ASP plateau and CDP study reveals that ASP plume composition is inherited from oceanic crust and pelagic sediments recycled in the mantle through a 1.5 Ga subduction process. The ASP plateau lavas have a composition (major and trace elements and Sr-Nd-Pb-Hf isotopes) reflecting the interaction between ASP plume and the Indian MORB mantle, including some clear DUPAL input. The Indian upper mantle below ASP plateau is heterogeneous and made of a depleted mantle with lower continental crust (LCC) fragments probably delaminated during the Gondwana break-up. The lower continental crust is one of the possible reservoirs for the DUPAL anomaly origin that our data support. The range of magnitude of each end-member required in ASP plateau samples is (1) 45% to 75% of ASP plume and (2) 25% to 55% of Indian DM within 0% to a maximum of 6% of LCC layers included within. The three end-members involved (plume, upper mantle and lower continental crust) and their mixing in different proportions enhances the geochemical variability in the plateau lavas. Consequently, the apparent composition homogeneity of Amsterdam Island, an aerial summit of the plateau, may result from the presence of intermediate magmatic chambers into the plateau structure.

  11. Composition and Localization of Treponema denticola Outer Membrane Complexes ▿

    PubMed Central

    Godovikova, Valentina; Goetting-Minesky, M. Paula; Fenno, J. Christopher

    2011-01-01

    The Treponema denticola outer membrane lipoprotein-protease complex (dentilisin) contributes to periodontal disease by degrading extracellular matrix components and disrupting intercellular host signaling pathways. We recently demonstrated that prcB, located upstream of and cotranscribed with prcA and prtP, encodes a 22-kDa lipoprotein that interacts with PrtP and is required for its activity. Here we further characterize products of the protease locus and their roles in expression, formation, and localization of outer membrane complexes. PrcB migrates in native gels as part of a >400-kDa complex that includes PrtP and PrcA, as well as the major outer sheath protein Msp. PrcB is detectable as a minor constituent of the purified active protease complex, which was previously reported to consist of only PrtP and auxiliary polypeptides PrcA1 and PrcA2. Though it lacks the canonical ribosome binding site present upstream of both prcA and prtP, PrcB is present at levels similar to those of PrtP in whole-cell extracts. Immunofluorescence microscopy demonstrated cell surface exposure of the mature forms of PrtP, PrcA1, PrcB, and Msp. The 16-kDa N-terminal acylated fragment of PrtP (predicted to be released during activation of PrtP) was present in cell extracts but was detected neither in the purified active protease complex nor on the cell surface. PrcA2, detectable on the surface of Msp-deficient cells but not that of wild-type cells, coimmunoprecipitated with Msp. Our results indicate that PrcB is a component of the outer membrane lipoprotein protease complex and that Msp and PrcA2 interaction may mediate formation of a very-high-molecular-weight outer membrane complex. PMID:21986628

  12. Outer brain barriers in rat and human development

    PubMed Central

    Brøchner, Christian B.; Holst, Camilla B.; Møllgård, Kjeld

    2015-01-01

    Complex barriers at the brain's surface, particularly in development, are poorly defined. In the adult, arachnoid blood-cerebrospinal fluid (CSF) barrier separates the fenestrated dural vessels from the CSF by means of a cell layer joined by tight junctions. Outer CSF-brain barrier provides diffusion restriction between brain and subarachnoid CSF through an initial radial glial end feet layer covered with a pial surface layer. To further characterize these interfaces we examined embryonic rat brains from E10 to P0 and forebrains from human embryos and fetuses (6–21st weeks post-conception) and adults using immunohistochemistry and confocal microscopy. Antibodies against claudin-11, BLBP, collagen 1, SSEA-4, MAP2, YKL-40, and its receptor IL-13Rα2 and EAAT1 were used to describe morphological characteristics and functional aspects of the outer brain barriers. Claudin-11 was a reliable marker of the arachnoid blood-CSF barrier. Collagen 1 delineated the subarachnoid space and stained pial surface layer. BLBP defined radial glial end feet layer and SSEA-4 and YKL-40 were present in both leptomeningeal cells and end feet layer, which transformed into glial limitans. IL-13Rα2 and EAAT1 were present in the end feet layer illustrating transporter/receptor presence in the outer CSF-brain barrier. MAP2 immunostaining in adult brain outlined the lower border of glia limitans; remnants of end feet were YKL-40 positive in some areas. We propose that outer brain barriers are composed of at least 3 interfaces: blood-CSF barrier across arachnoid barrier cell layer, blood-CSF barrier across pial microvessels, and outer CSF-brain barrier comprising glial end feet layer/pial surface layer. PMID:25852456

  13. Wisps in the outer edge of the Keeler Gap

    NASA Astrophysics Data System (ADS)

    Tiscareno, Matthew S.; Arnault, Ethan G.

    2015-11-01

    Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear.Aside from the wisps, the Keeler Gap outer edge is the only one of the five sharp edges in the outer part of Saturn's A ring that is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). The other four (the inner and outer edges of the Encke Gap, the inner edge of the Keeler Gap, and the outer edge of the A ring itself) are characterized by wavy structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS).We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

  14. Measuring In Vivo Free Radical Production by the Outer Retina

    PubMed Central

    Berkowitz, Bruce A.; Bredell, Bryce X.; Davis, Christopher; Samardzija, Marijana; Grimm, Christian; Roberts, Robin

    2015-01-01

    Purpose Excessive and continuously produced free radicals in the outer retina are implicated in retinal aging and the pathogenesis of sight-threatening retinopathies, yet measuring outer retinal oxidative stress in vivo remains a challenge. Here, we test the hypothesis that continuously produced paramagnetic free radicals from the outer retina can be measured in vivo using high-resolution (22-μm axial resolution) 1/T1magnetic resonance imaging (MRI) without and with a confirmatory quench (quench-assisted MRI). Methods Low-dose sodium iodate–treated and diabetic C57Bl6/J mice (and their controls), and rod-dominated (129S6) or cone-only R91W;Nrl−/− mice were studied. In dark-adapted groups, 1/T1 was mapped transretinally in vivo without or with (1) the antioxidant combination of methylene blue (MB) and α-lipoic acid (LPA), or (2) light exposure; in subgroups, retinal superoxide production was measured ex vivo (lucigenin). Results In the sodium iodate model, retinal superoxide production and outer retina-specific 1/T1 values were both significantly greater than normal and corrected to baseline with MB+LPA therapy. Nondiabetic mice at two ages and 1.2-month diabetic mice (before the appearance of oxidative stress) had similar transretinal 1/T1 profiles. By 2.3 months of diabetes, only outer retinal 1/T1 values were significantly greater than normal and were corrected to baseline with MB+LPA therapy. In mice with healthy photoreceptors, a light quench caused 1/T1 of rods, but not cones, to significantly decrease from their values in the dark. Conclusions Quench-assisted MRI is a feasible method for noninvasively measuring normal and pathologic production of free radicals in photoreceptors/RPE in vivo. PMID:26670830

  15. Contribution of bacterial outer membrane vesicles to innate bacterial defense

    PubMed Central

    2011-01-01

    Background Outer membrane vesicles (OMVs) are constitutively produced by Gram-negative bacteria throughout growth and have proposed roles in virulence, inflammation, and the response to envelope stress. Here we investigate outer membrane vesiculation as a bacterial mechanism for immediate short-term protection against outer membrane acting stressors. Antimicrobial peptides as well as bacteriophage were used to examine the effectiveness of OMV protection. Results We found that a hyper-vesiculating mutant of Escherichia coli survived treatment by antimicrobial peptides (AMPs) polymyxin B and colistin better than the wild-type. Supplementation of E. coli cultures with purified outer membrane vesicles provided substantial protection against AMPs, and AMPs significantly induced vesiculation. Vesicle-mediated protection and induction of vesiculation were also observed for a human pathogen, enterotoxigenic E. coli (ETEC), challenged with polymyxin B. When ETEC with was incubated with low concentrations of vesicles concomitant with polymyxin B treatment, bacterial survival increased immediately, and the culture gained resistance to polymyxin B. By contrast, high levels of vesicles also provided immediate protection but prevented acquisition of resistance. Co-incubation of T4 bacteriophage and OMVs showed fast, irreversible binding. The efficiency of T4 infection was significantly reduced by the formation of complexes with the OMVs. Conclusions These data reveal a role for OMVs in contributing to innate bacterial defense by adsorption of antimicrobial peptides and bacteriophage. Given the increase in vesiculation in response to the antimicrobial peptides, and loss in efficiency of infection with the T4-OMV complex, we conclude that OMV production may be an important factor in neutralizing environmental agents that target the outer membrane of Gram-negative bacteria. PMID:22133164

  16. Identification of outer membrane proteins of Mycobacterium tuberculosis.

    PubMed

    Song, Houhui; Sandie, Reatha; Wang, Ying; Andrade-Navarro, Miguel A; Niederweis, Michael

    2008-11-01

    The cell wall of mycobacteria includes an unusual outer membrane of extremely low permeability. While Escherichia coli uses more than 60 proteins to functionalize its outer membrane, only two mycobacterial outer membrane proteins (OMPs) are known. The porin MspA of Mycobacterium smegmatis provided the proof of principle that integral mycobacterial OMPs share the beta-barrel structure, the absence of hydrophobic alpha-helices and the presence of a signal peptide with OMPs of gram-negative bacteria. These properties were exploited in a multi-step bioinformatic approach to predict OMPs of M. tuberculosis. A secondary structure analysis was performed for 587 proteins of M. tuberculosis predicted to be exported. Scores were calculated for the beta-strand content and the amphiphilicity of the beta-strands. Reference OMPs of gram-negative bacteria defined threshold values for these parameters that were met by 144 proteins of unknown function of M. tuberculosis. Two of them were verified as OMPs by a novel two-step experimental approach. Rv1698 and Rv1973 were detected only in the total membrane fraction of M. bovis BCG in Western blot experiments, while proteinase K digestion of whole cells showed the surface accessibility of these proteins. These findings established that Rv1698 and Rv1973 are indeed localized in the outer membrane and tripled the number of known OMPs of M. tuberculosis. Significantly, these results provide evidence for the usefulness of the bioinformatic approach to predict mycobacterial OMPs and indicate that M. tuberculosis likely has many OMPs with beta-barrel structure. Our findings pave the way to identify the set of proteins which functionalize the outer membrane of M. tuberculosis. PMID:18439872

  17. Scaling behavior of the quantum Hall plateau-plateau transition in graphene p-n-p junctions

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Hua; Liu, Cheng-Hua; Wang, Po-Hsiang; Woo, Tak-Pong; Chen, Chun-Wei; Liang, Chi-Te

    We present the observation of scaling behavior in graphene p-n-p junctions achieved by controlled metallic diffusion. Generally, metal deposition on graphene surface introduces substantial carrier scattering, which undermines the high mobility of intrinsic graphene. However, we discover a weakly functionalized regime of the deposited contact with small carrier scattering, while p-type doping of graphene is realized due to the metal oxide formation. Consequently, the resulted graphene channel are composed of p-type doped and an intrinsic regions. The high-quality graphene p-n-p junctions is evidenced by a pronounced quantum Hall effect and Shubnikov-de Haas oscillations. Remarkably, we observed a well-defined QH plateau-plateau transition of zeroth Landau level, yielding a scaling exponent of ∖kappa =0.21 ∖pm0.01. Moreover, the graphene p-n-p junctions exhibit weak localization behavior, and the coherence length was found to be correlated to carrier scattering in the graphene devices.

  18. Synchronization and plateau splitting of coupled oscillators with long-range power-law interactions

    NASA Astrophysics Data System (ADS)

    Kuo, Huan-Yu; Wu, Kuo-An

    2015-12-01

    We investigate synchronization and plateau splitting of coupled oscillators on a one-dimensional lattice with long-range interactions that decay over distance as a power law. We show that in the thermodynamic limit the dynamics of systems of coupled oscillators with power-law exponent α ≤1 is identical to that of the all-to-all coupling case. For α >1 , oscillatory behavior of the phase coherence appears as a result of single plateau splitting into multiple plateaus. A coarse-graining method is used to investigate the onset of plateau splitting. We analyze a simple oscillatory state formed by two plateaus in detail and propose a systematic approach to predict the onset of plateau splitting. The prediction of breaking points of plateau splitting is in quantitatively good agreement with numerical simulations.

  19. The diverse crustal structure and magmatic evolution of the Manihiki Plateau, central Pacific

    NASA Astrophysics Data System (ADS)

    Hochmuth, K.; Gohl, K.; Uenzelmann-Neben, G.; Werner, R.

    2014-07-01

    The Manihiki Plateau is a Large Igneous Province (LIP) in the central Pacific. It was emplaced as part of the "Super-LIP" Ontong Java Nui and experienced fragmentation into three sub-plateaus, possibly during the break-up of Ontong Java Nui. The Manihiki Plateau is presumably the centerpiece of this "Super-LIP" and its investigation can therefore decipher the break-up mechanisms as well as the evolution of the plateau after its initial emplacement. By analyzing two seismic refraction/wide-angle reflection profiles crossing the two largest sub-plateaus of the Manihiki Plateau, the High Plateau and the Western Plateaus, we give new insights into their crustal structure and magmatic evolution. The High Plateau shows a crustal structure of 20 km thickness and a seismic P wave velocity distribution, which is comparable to other LIPs. The High Plateau experienced a strong secondary volcanism, which can be seen in relicts of seamount chain volcanism. The Western Plateaus on the other hand show no extensive secondary volcanism and are mainly structured by fault systems and sedimentary basins. A constant decrease in Moho depth (9-17 km) is a further indicator of crustal stretching on the Western Plateaus. Those findings lead to the conclusion, that the two sub-plateaus of the Manihiki Plateau experienced a different magmatic and tectonic history. Whereas the High Plateau experienced a secondary volcanism, the Western Plateaus underwent crustal stretching during and after the break-up of Ontong Java Nui. This indicates, that the sub-plateaus of the Manihiki Plateau play an individual part in the break-up history of Ontong Java Nui.

  20. Enhancing the Early Differential Diagnosis of Plateau Iris and Pupillary Block Using A-Scan Ultrasonography

    PubMed Central

    Chen, Yu-Yen; Chu, Dachen; Chou, Pesus

    2015-01-01

    Purpose To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy. Methods In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes. Results The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001), thicker lens (4.77mm vs. 5.11mm; p<0.001), shorter axial length (23.16mm vs. 22.63mm; p<0.001), smaller relative lens position (2.28 vs. 2.16; p<0.001) and larger lens/axial length factor (2.06 vs. 2.26; p<0.001). However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05). Conclusions Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes. PMID:25689856

  1. The change of the Tibetan Plateau climate system and its impact on eastern Asia

    NASA Astrophysics Data System (ADS)

    Ma, Yaoming

    2015-04-01

    As the Third Pole of the earth, the Tibetan Plateau is an important water source of Asia. The 10 major rivers in China and abroad developed from the Tibet Plateau and provide living and production water for 1/3 of the world's population in East Asia and South Asia. The powerful dynamic and thermal effects of the Tibet Plateau significantly affect the East Asian climate pattern, the process of the Asian monsoon and Northern Hemisphere atmospheric circulation. Global change influences the processes of hydrosphere and cryosphere on the Tibetan Plateau, changes the ecosystem and environment within the plateau, and affects the socio-economic development and living condition of people in the region. In addition to that, through atmospheric circulation and water cycle, global change directly impacts water security and nature disaster protection in East Asia and surrounding nations. In order to study on the change of the Tibetan Plateau climate system and the mechanism of its impact on eastern Asia, one Chinese national research programme was launched in 2010. The research progresses of the programme in the past five years will be introduced. The research progresses are including four parts: the establishment an integrated network platform for the Tibetan Plateau and its surrounding area "water - cryosphere -atmosphere -biology" observation, the study on the relation between the Tibet Plateau land surface-atmosphere interaction and atmospheric circulation anomalies, the study on the interactions among atmosphere, cryosphere, hydrosphere, and biosphere on the Tibetan Plateau feeding back to climate change,and the study on the Tibetan Plateau climate system feeding back to East Asian regional climate change and its mechanism.

  2. Grand Tour outer planet missions definition phase. Part 1: Quantitative imaging of the outer planets and their satellites

    NASA Technical Reports Server (NTRS)

    Belton, M. J. S.; Aksnes, K.; Davies, M. E.; Hartmann, W. K.; Millis, R. L.; Owen, T. C.; Reilly, T. H.; Sagan, C.; Suomi, V. E.; Collins, S. A., Jr.

    1972-01-01

    A recommended imaging system is outlined for use aboard the Outer Planet Grand Tour Explorer. The system features the high angular resolution capacity necessary to accommodate large encounter distances, and to satisfy the demand for a reasonable amount of time coverage. Specifications for all components within the system are provided in detail.

  3. Tidal forcing, energetics, and mixing near the Yermak Plateau

    NASA Astrophysics Data System (ADS)

    Fer, I.; Müller, M.; Peterson, A. K.

    2015-03-01

    The Yermak Plateau (YP), located northwest of Svalbard in Fram Strait, is the final passage for the inflow of warm Atlantic Water into the Arctic Ocean. The region is characterized by the largest barotropic tidal velocities in the Arctic Ocean. Internal response to the tidal flow over this topographic feature locally contributes to mixing that removes heat from the Atlantic Water. Here, we investigate the tidal forcing, barotropic-to-baroclinic energy conversion rates, and dissipation rates in the region using observations of oceanic currents, hydrography, and microstructure collected on the southern flanks of the plateau in summer 2007, together with results from a global high-resolution ocean circulation and tide model simulation. The energetics (depth-integrated conversion rates, baroclinic energy fluxes and dissipation rates) show large spatial variability over the plateau and are dominated by the luni-solar diurnal (K1) and the principal lunar semidiurnal (M2) constituents. The volume-integrated conversion rate over the region enclosing the topographic feature is approximately 1 GW and accounts for about 50% of the M2 and approximately all of the K1 conversion in a larger domain covering the entire Fram Strait extended to the North Pole. Despite the substantial energy conversion, internal tides are trapped along the topography, implying large local dissipation rates. An approximate local conversion-dissipation balance is found over shallows and also in the deep part of the sloping flanks. The baroclinic energy radiated away from the upper slope is dissipated over the deeper isobaths. From the microstructure observations, we inferred lower and upper bounds on the total dissipation rate of about 0.5 and 1.1 GW, respectively, where about 0.4-0.6 GW can be attributed to the contribution of hot spots of energetic turbulence. The domain-integrated dissipation from the model is close to the upper bound of the observed dissipation, and implies that almost the entire

  4. Glacier elevation changes on the Tibetan Plateau derived by ICESat

    NASA Astrophysics Data System (ADS)

    Neckel, N.; Kropacek, J.; Bolch, T.

    2012-04-01

    Glaciers are a sensitive indicator for climate change in high mountain regions where climate stations are rare or non-existent. In addition, glacier changes have a significant impact on the hydrological cycle of the vulnerable region of the Tibetan Plateau. Therefore a continuous monitoring of glaciers is necessary. In-situ measurements are essential but can only be conducted at a very limited number of glaciers in this large and remote region due to enormous logistical efforts and high costs. Remote sensing techniques are suitable to complement these in-situ measurements and address a large area simultaneously. Traditionally, mountain glaciers are monitored in terms of area changes from aerial or satellite image data. However, these changes show, in contrast to volume changes, a delayed signal to climate only. In order to estimate volume changes of glaciers on the Tibetan Plateau data from the Geoscience Laser Altimeter System (GLAS) carried on-board the Ice Cloud and Elevation Satellite (ICESat) was used for extraction of elevation changes for the period 2003 to 2009. GLAS shots over glaciers were selected using the Global Land Ice Measurements from Space (GLIMS) dataset with support of recent cloud free Landsat scenes obtained from USGS. ICESat repeat-tracks are spatially close but do not match exactly. They can be horizontally separated by up to 3000 m. Therefore, an independent reference surface is used for a multi-temporal comparison of GLAS shots. For this purpose we use a Digital Elevation Model (DEM) acquired in February 2000 by the Shuttle Radar Topography Mission (SRTM). Glaciers with an adequate ICESat data coverage (approximately 12% of the glaciers captured in the GLIMS database) were grouped according to the mountain chains in certain compact geographic regions. Mean trends in glacier elevation changes were estimated for these regions for the seven years of ICESat's lifetime. Preliminary results suggest a heterogeneous wastage of glaciers across the

  5. Middle Pleistocene infill of Tibetan Plateau margin rivers, Zanskar, India

    NASA Astrophysics Data System (ADS)

    Munack, Henry; Blöthe, Jan; Korup, Oliver; Fülöp, Réka-Hajnalka; Codilean, Alexandru T.; Fink, David

    2015-04-01

    The Indus, one of Asia's premier rivers, drains the NW Himalaya and the Transhimalayan ranges that fringe the western Tibetan Plateau margin. There, upstream of the western Himalayan syntaxis, river valleys alternate between deeply incised bedrock gorges and broad alluviated reaches, while average denudation rates decrease by an order of magnitude towards the Tibetan Plateau margin to rates of ~10 mm ka-1. Vast fill terrace staircases, the highest of them located up to 400 m above current river level, and intercalated lake sediments indicate alternating phases of incision and aggradation within the region, underlining the high landform preservation potential in the rain shadow of the High Himalaya. However, despite a broad interest in a better understanding of mechanisms that modulate plateau erosion, age constraints on the generation of these impressive features are sparse, though indicate mainly Pleistocene formation ages. We present new age constraints from the More Plains section in the headwaters of the Zanskar River, a major tributary to the upper Indus. The vast sedimentary successions of the More Plains originally belonged to a former endorheic basin that has been tapped by the Zanskar River, today revealing exposures of >250 m of sedimentary fill that continues to smother a previously dissected alpine headwater landscape. We combine 10Be surface exposure dating and catchment-averaged denudation rates, morphometric analysis and field observation to constrain the late Quaternary history of this section. Analysis of a 10Be depth profile on top of the More Plains, together with the dating of nearby amalgamated surface samples, indicate a surface exposure of ~170 +/- 20 ka such that deposition of this valley fill ceased during a Middle Pleistocene cold stage (MIS 6). Using GIS-based algorithms we estimate that ~3.6 km3 was removed from this section by fluvial erosion, requiring a specific sediment yield of >130 t km-2 yr-1 averaged over the past 170 ka. This

  6. Outer boundary conditions for evolving cool white dwarfs

    NASA Astrophysics Data System (ADS)

    Rohrmann, R. D.; Althaus, L. G.; García-Berro, E.; Córsico, A. H.; Miller Bertolami, M. M.

    2012-10-01

    Context. White dwarf evolution is essentially a gravothermal cooling process, which, for cool white dwarfs, depends on the treatment of the outer boundary conditions. Aims: We provide detailed outer boundary conditions that are appropriate to computing the evolution of cool white dwarfs by employing detailed nongray model atmospheres for pure hydrogen composition. We also explore the impact on the white dwarf cooling times of different assumptions for energy transfer in the atmosphere of cool white dwarfs. Methods: Detailed nongray model atmospheres were computed by considering nonideal effects in the gas equation of state and chemical equilibrium, collision-induced absorption from molecules, and the Lyman α quasi-molecular opacity. We explored the impact of outer boundary conditions provided by updated model atmospheres on the cooling times of 0.60 and 0.90 M⊙ white dwarf sequences. Results: Our results show that the use of detailed outer boundary conditions becomes relevant for effective temperatures lower than 5800 K for sequences with 0.60 M⊙ and 6100 K with 0.90 M⊙. Detailed model atmospheres predict ages that are up to ≈10% shorter at log (L/L⊙) = -4 when compared with the ages derived using Eddington-like approximations at τRoss = 2/3. We also analyze the effects of various assumptions and physical processes that are relevant in the calculation of outer boundary conditions. In particular, we find that the Lyα red wing absorption does not substantially affect the evolution of white dwarfs. Conclusions: White dwarf cooling timescales are sensitive to the surface boundary conditions for Teff ≲ 6000 K. Interestingly enough, nongray effects have few consequences on these cooling times at observable luminosities. In fact, collision-induced absorption processes, which significantly affect the spectra and colors of old white dwarfs with hydrogen-rich atmospheres, have no noticeable effects on their cooling rates, except throughout the Rosseland mean

  7. Star formation in the outer disks of spiral galaxies

    NASA Astrophysics Data System (ADS)

    Barnes, Kate Lynn

    I present results from a multi-wavelength study of star formation and the gaseous content in the outer disks of a sample of eight nearby spiral galaxies. In particular, the study focuses on galaxies with typical HI-to-optical sizes of ˜1--2, to provide a comparison to studies of galaxies with star formation occurring in extended gas disks. The study features new, ultra-deep ground-based H-alpha imaging and deep ultraviolet (UV) imaging from the GALEX space telescope to trace the recent star formation. I find that star formation typically extends through most (>85%) of the gas disk, with an outermost star forming regime characterized by low covering fractions and low star formation rate surface densities. The result that star formation extends through most of the gas disk regardless of the HI-to-optical size implies that it is important to further our understanding of the formation of extended gas disks to fully understand the implications of extended star forming disks. I find that the outer gaseous disks are gravitationally stable, which is in agreement with the lower level of star formation. I use ultraviolet and H-alpha colors to probe the recent star formation in the outer disks and find significant variations between colors of young stellar clusters. I run stellar population synthesis models to show how episodic star formation histories (SFHs) with periods of 100--250 Myr could cause similar color variations as are seen in outer disks. An episodic SFH would have implications for the gas depletion time and chemical evolution of spiral galaxies. In addition to an episodic SFH, the observed ultraviolet and H-alpha colors of young stellar clusters in the outer disks of galaxies in our sample are also in agreement with recently published models of a stochastically sampled initial mass function (IMF). Therefore, there remains some uncertainty for the possible cause of this observational result. Finally, we present a pilot study of deep, near infrared (NIR) imaging

  8. THE COLORS OF EXTREME OUTER SOLAR SYSTEM OBJECTS

    SciTech Connect

    Sheppard, Scott S.

    2010-04-15

    Extreme outer solar system objects have possible origins beyond the Kuiper Belt edge, high inclinations, very large semimajor axes, or large perihelion distances. Thirty-three such objects were observed in this work to determine their optical colors. All three objects that have been dynamically linked to the inner Oort Cloud by various authors ((90377) Sedna, 2006 SQ{sub 372}, and (87269) 2000 OO{sub 67}) were found to have ultra-red surface material (spectral gradient, S {approx} 25). Ultra-red material is generally associated with rich organics and the low inclination 'cold' classical Kuiper Belt objects (KBOs). The observations detailed here show that very red material may be a more general feature for objects kept far from the Sun. The recently discovered retrograde outer solar system objects (2008 KV{sub 42} and 2008 YB{sub 3}) and the high inclination object (127546) 2002 XU{sub 93} show only moderately red surfaces (S {approx} 9) very similar to known comets, suspected dead comets, Jupiter and Neptune Trojans, irregular satellites, D-type asteroids, and damocloids. The extended or detached disk objects, which have large perihelion distances and are thus considered to be detached from the influence of the giant planets but yet have large eccentricities, are found to have mostly moderately red colors (10 {approx}< S {approx}< 18). The colors of the detached disk objects, including the dynamically unusual 2004 XR{sub 190} and (148209) 2000 CR{sub 105}, are similar to the scattered disk and Plutino populations. Thus the detached disk, scattered disk, Plutino, and high inclination 'hot' classical objects likely have a similar mix of objects from the same source regions. Outer classical KBOs, including (48639) 1995 TL{sub 8}, were found to have very red surfaces (18 {approx}< S {approx}< 30). The low inclination 'cold' classical KBOs, outer classical KBOs and possibly the inner Oort Cloud appear to be dominated by ultra-red objects (S {approx}> 25) and thus do not

  9. Plateau structures in potential scattering in a strong laser field

    SciTech Connect

    Cerkic, A.; Milosevic, D.B.

    2004-11-01

    Electron-atom scattering in a strong laser field is analyzed using the strong-field approximation and modeling elastic scattering of electrons by atoms with a realistic analytical potential derived from an independent-particle model. The results that include both direct scattering and scattering with a repeated scattering (rescattering) are presented. In the latter case, in the intermediate step of the process, the electron can absorb the energy from the laser field and additional plateau structures appear. The features of these plateaus and their cutoffs are analyzed for various incident electron energies and scattering angles, for different laser intensities, and for various atomic gases. The boundaries of these plateaus are compared with classical estimates.

  10. Future landscapes of the Colorado Plateau: impacts of energy development

    SciTech Connect

    deBuys, W.E. Jr.; Doughty, R.W.

    1982-07-01

    This study is part of a continuing effort to analyze basic energy issues. The issues addressed here include the transformations taking place on the Colorado Plateau in the areas of mine reclamation, wildlife protection, surface and groundwater allocation, air quality management, and boomtown growth. This study treats these subjects in a unified fashion as constituent elements of a single entity called the cultual landscape. That term refers not only to the geophysical realities of topography, vegetation, and animal life, but also to the cultural realities of man's impact on environment and on himself. By taking this holistic approach, the study aspires to render a more complete and balanced portrait of the region's future than one usually finds in the literature of impact assessment.

  11. Observations of Ionospheric Features over the Anatolian Plateau

    NASA Astrophysics Data System (ADS)

    Garner, T. W.; Slack, C. M.; Scholze, A.; Mehta, K.; Mahrous, A.

    2010-12-01

    Helwan University and the Applied Research Laboratories at the University of Texas have collaborated to field the Ionospheric Tomography Network of Egypt (ITNE). ITNE consists of 3 UHF/VHF beacon receivers across Egypt. The first of these receivers was placed in Helwan, Egypt. It frequently observes a peak in ΔTEC/Δt measurements where the F-region intercept of the radio rays crosses the southern edge of the Anatolian Plateau. This feature was observed repeatedly in passes over Anatolia during the summer of 2008. The ΔTEC/Δt peaks occur where the 300 km intercept passes over the edge. Visually the ΔTEC/Δt peaks are correlated with steep surface topography gradients. These correlations suggest that the local ionosphere is affected by the ground topography, possibly through the upward propagation of mountain-generated gravity waves.

  12. Plateau inflation from random non-minimal coupling

    NASA Astrophysics Data System (ADS)

    Broy, Benedict J.; Coone, Dries; Roest, Diederik

    2016-06-01

    A generic non-minimal coupling can push any higher-order terms of the scalar potential sufficiently far out in field space to yield observationally viable plateau inflation. We provide analytic and numerical evidence that this generically happens for a non-minimal coupling strength ξ of the order N2e. In this regime, the non-minimally coupled field is sub-Planckian during inflation and is thus protected from most higher-order terms. For larger values of ξ, the inflationary predictions converge towards the sweet spot of PLANCK. The latter includes ξ simeq 104 obtained from CMB normalization arguments, thus providing a natural explanation for the inflationary observables measured.

  13. New Seismic Array Observation in the Northwestern Iranian Plateau

    NASA Astrophysics Data System (ADS)

    Chen, Ling; Jiang, Mingming; Talebian, Morteza; Ghods, Abdolreza; Chung, Sun-Lin; Ai, Yinshuang; Sobouti, Farhad; He, Yumei; Motaghi, Khalil; Zheng, Tianyu; Faridi, Mohammad; Chen, Qi-Fu; Lyu, Yan; Xiao, Wenjiao; Khalatbari Jafari, Morteza; Zhu, Rixiang

    2016-04-01

    The Iranian Plateau, being formed as a consequence of the on-going Arabia-Eurasia collision, is a natural laboratory for understanding mountain/plateau building processes and deep dynamics related to the early phases of continent-continent collision. A key issue in the study of the Iranian Plateau is to acquire detailed information about the structure and deformation of the crust and mantle. For this purpose, we (IGGCAS, RIESGSI, IASBS) deployed a new temporary broadband seismic array in NW Iran, under a multidisciplinary collaborative project named "China-Iran Geological and Geophysical Survey in the Iranian Plateau (CIGSIP)". The new array consists of three linear sub-arrays running northeastward from the south of the Zagros Fold and Thrust Belt to the coast area of the southern Caspian Sea, forming an observational corridor of ~550-km long and ~150-km wide. The main sub-array consists of 46 stations with station spacing of 10-15 km. Eight and nine additional stations were located ~75 km to the west and east, respectively, of the main sub-array to provide 3D constraints on the deep structure. All the 63 stations operated for about one year from October 2013 to October 2014. We investigate the crustal and upper mantle structure beneath this new seismic array by combining P- and S-receiver function (RF) images with ambient noise tomography and gravity modeling results. Our images reveal substantial structural variations in the crust of different tectonic units that are bounded by major strike-slip faults. The Main Zagros Reverse Fault (MZRF), generally considered as the suture between the Arabian and Eurasian plates, was imaged to dip to NE, separating an overall slow crust but with a faster and denser lowermost part in the SW Arabian side from a relatively fast crust, especially a fast middle-lower crust in the NE Iranian side. Structural differences are also observed between the Alborz Mountains and the southern Caspian Sea where an apparent Moho step (~18 km

  14. New observations of Meddy Movement south of the Tejo Plateau

    NASA Astrophysics Data System (ADS)

    Zenk, Walter; Schultz Tokos, Kathy; Boebel, Olaf

    1992-12-01

    Mediterranean salt lenses (meddies) are a dominant factor in the salt budget of the Atlantic at middepth. In spite of their important role, their juvenile migration has not yet been directly observed. For the first time, two RAFOS float trajectories show strong evidence of a meddy along the Iberian continental slope off Lisbon. Over six weeks we obtained drift observations from two levels (629, 847 dbar). Both instruments recorded a series of loops with an azimuthal speed O (30 cm s-1) at a radius of about 25 km. Relatively high propagation speeds of several centimeters per second indicate the meddy was probably carried along with the undercurrent of Mediterranean Water. The Tejo Plateau, a prominent feature of the continental slope and a natural obstacle for the spreading Mediterranean Water tongue, appears to act as a deflector for advected meddies possibly formed by interaction of the undercurrent with the canyon-rich topography farther south.

  15. Extension during continental convergence, with application to the Tibetan Plateau

    NASA Technical Reports Server (NTRS)

    England, Philip; Houseman, Gregory

    1989-01-01

    An explanation in terms of the thermal evolution of thickened continental lithosphere is offered to explain the transition, in the late Tertiary to Quaternary, from north-south compression to east-west extension in the strain rate field of the Tibetan Plateau. The lower part of the lithosphere consists of a thermal boundary layer which, when thickened by horizontal shortening, is colder and denser than its surroundings. Convective instability of the thickened thermal boundary layer and its replacement by hot asthenosphere would rapidly raise the surface elevation and gravitational potential energy of the overlying part of the lithosphere. The convective instability would happen in a time brief compared with the collision time scale but would only occur after there had already been substantial thickening of the lithosphere. The increase in surface height and of potential energy are sufficient for east-west extension to replace north-south compression as the dominant feature of the stress field.

  16. 200-Area plateau inactive miscellaneous underground storage tanks locations

    SciTech Connect

    Brevick, C.H.

    1997-12-01

    Fluor Daniel Northwest (FDNW) has been tasked by Lockheed Martin Hanford Corporation (LMHC) to incorporate current location data for 64 of the 200-Area plateau inactive miscellaneous underground storage tanks (IMUST) into the centralized mapping computer database for the Hanford facilities. The IMUST coordinate locations and tank names for the tanks currently assigned to the Hanford Site contractors are listed in Appendix A. The IMUST are inactive tanks installed in underground vaults or buried directly in the ground within the 200-East and 200-West Areas of the Hanford Site. The tanks are categorized as tanks with a capacity of less than 190,000 liters (50,000 gal). Some of the IMUST have been stabilized, pumped dry, filled with grout, or may contain an inventory or radioactive and/or hazardous materials. The IMUST have been out of service for at least 12 years.

  17. Analysis of turbulence characteristics over the northern Tibetan Plateau area

    NASA Astrophysics Data System (ADS)

    Li, M. S.; Ma, Y. M.; Ma, W. Q.; Hu, Z. Y.; Ishikawa, H.; Su, Z. B.; Sun, G. L.

    2006-07-01

    Based on CATOP/Tibet [Coordinated Enhanced Observing Period (CEOP) Asia-Australia Monsoon Project (CA-IMP) on the Tibetan Plateau) turbulent data collected at the Bujiao (BJ) site of the Nagqu area, the turbulent structure and transportation characteristics in the near surface layer during summer are analyzed. The main results show that the relationship between the normalized standard deviation of 3D wind speed and stability satisfies the similarity law tinder both unstable and stable stratifications. The relations of normalized standard deviation of temperature and specific humidity to stability only obey the "-1/3 power law." tinder unstable conditions. In the case of stable stratifications, their relations to stability are dispersing. The sensible heat dominates in the dry period, while in the wet period, the latent heat is larger than the sensible heat.

  18. Subtropical circulation, Tibetan Plateau, and Asian Summer Monsoon

    NASA Astrophysics Data System (ADS)

    Wu, G. X.

    2015-12-01

    The characteristics of the land-air-sea interaction in summer subtropics and their impacts on climate were revealed. It was shown that different kind of diabatic heating plays different roles in the formation of the subtropical circulation where the surface sensible heating associated with the land-sea distribution plays a fundamentally important role, and the three spatial- scales of atmospheric forcing contribute in various ways to the formation of aridity/desert over the western parts of continents and wet/monsoon over the eastern parts. Thus monsoon and desert coexist as twin features. It was identified that the onset of the Asian summer monsoon (ASM) consists of three dynamically consequential stages: the onset first occurs over the eastern Bay of Bengal (BOB) in early May, which is followed by the onset over the South China Sea in mid-May, and the Indian Monsoon onset in early June. During such an onset progression, the formation, maintenance and evolution of the South Asian High (SAH) play a significant role in generating the upper tropospheric dumping. In the lower troposphere, the development of the BOB monsoon onset vortex, the ASM onset barrier, the cross equatorial SST gradient and the forced convection over the eastern Arabian Sea also regulate the onset evolution. In winter the Tibetan Plateau (TP) can inspire a stationary dipole-type atmospheric wave, forming a specific climate pattern in Asia. In spring, such a dipole circulation forms the unique persistent rainfall over Southern China. The TP forcing can also anchor the ASM onset over the BOB by generating the unique short- life BOB SST warm pool and modulating the SAH in the upper troposphere. In summer the thermal forcing of the Tibetan-Iranian Plateau plays a significant role in controlling the Asian monsoon by transporting water vapor from the sea to the land for the genesis of continental monsoon. The TP thermal forcing also modulates the regional climate variability in different time scales.

  19. Relationship between gullying and landslides within the Barlad Plateau, Romania

    NASA Astrophysics Data System (ADS)

    Niacsu, Lilian; Ionita, Ion

    2016-04-01

    Located in the eastern Romania and extending on 8200 km2 the Barlad Plateau is considered the most typical subunit of the Moldavian Plateau. The sedimentary Miocene-Pliocene clay-sandy layers, inter-bedded with shallow sandstone and limestone are gently dipping toward S-SE as homoclinal structure. Land degradation through soil erosion, gullying and landslides represent the most important environmental threat in the region. By using both the classical research methods such as repeated field surveys and mapping, mathematical-statistical processing as well as the present-day methods based on the GIS software it was possible to precisely measure and evaluate the gully erosion rates and triggered landslides during the last two centuries, especially with a very high accuracy since 1960. Results have indicated that the landslide development is strongly controlled by gullying. Generally, by combining the areal growth of both gullying and new landslides within the selected study catchments, it is noticeable that 62 % of the total recent land degradation occurred during the last 55 years, with the remainder pre-1960. In addition, half of the gully areal growth occurred since 1961 but the new triggered landslides amount over three-quarters of the total area under landslides. This asymmetrical distribution reveals that usually a preparing time lag of tens of years is required for triggering landslides by gullying and this pattern depicts the common mechanism for landslide development. Acknowledgements: This work was partly supported by a grant from the Romanian National Authority for Scientific Research, CNDI-UEFISCDI, Project number PN-II-PT-PCCA-2011-3.2-0975.

  20. Ongoing speciation in the Tibetan plateau Gymnocypris species complex.

    PubMed

    Zhang, Renyi; Peng, Zuogang; Li, Guogang; Zhang, Cunfang; Tang, Yongtao; Gan, Xiaoni; He, Shunping; Zhao, Kai

    2013-01-01

    Local adaptation towards divergent ecological conditions often results in genetic differentiation and adaptive phenotypic divergence. To illuminate the ecological distinctiveness of the schizothoracine fish, we studied a Gymnocypris species complex consisting of three morphs distributed across four bodies of water (the Yellow River, Lake Qinghai, the Ganzi River and Lake Keluke) in the Northeast Tibetan Plateau. We used a combination of mitochondrial (16S rRNA and Cyt b) and nuclear (RAG-2) genetic sequences to investigate the phylogeography of these morphs based on a sample of 277 specimens. Analysis of gill rakers allowed for mapping of phenotypic trajectories along the phylogeny. The phylogenetic and morphological analyses showed that the three sparsely rakered morphs were present at two extremes of the phylogenetic tree: the Yellow River morphs were located at the basal phylogenetic split, and the Lake Keluke and Ganzi River morphs at the peak, with the densely rakered Lake Qinghai morphs located between these two extremes. Age estimation further indicated that the sparsely rakered morphs constituted the oldest and youngest lineages, whereas the densely rakered morph was assigned to an intermediate-age lineage. These results are most compatible with the process of evolutionary convergence or reversal. Disruptive natural selection due to divergent habitats and dietary preferences is likely the driving force behind the formation of new morphs, and the similarities between their phenotypes may be attributable to the similarities between their forms of niche tracking associated with food acquisition. This study provides the first genetic evidence for the occurrence of convergence or reversal in the schizothoracine fish of the Tibetan Plateau at small temporal scales. PMID:23977018

  1. Evaporative cooling over the Tibetan Plateau induced by vegetation growth.

    PubMed

    Shen, Miaogen; Piao, Shilong; Jeong, Su-Jong; Zhou, Liming; Zeng, Zhenzhong; Ciais, Philippe; Chen, Deliang; Huang, Mengtian; Jin, Chun-Sil; Li, Laurent Z X; Li, Yue; Myneni, Ranga B; Yang, Kun; Zhang, Gengxin; Zhang, Yangjian; Yao, Tandong

    2015-07-28

    In the Arctic, climate warming enhances vegetation activity by extending the length of the growing season and intensifying maximum rates of productivity. In turn, increased vegetation productivity reduces albedo, which causes a positive feedback on temperature. Over the Tibetan Plateau (TP), regional vegetation greening has also been observed in response to recent warming. Here, we show that in contrast to arctic regions, increased growing season vegetation activity over the TP may have attenuated surface warming. This negative feedback on growing season vegetation temperature is attributed to enhanced evapotranspiration (ET). The extra energy available at the surface, which results from lower albedo, is efficiently dissipated by evaporative cooling. The net effect is a decrease in daily maximum temperature and the diurnal temperature range, which is supported by statistical analyses of in situ observations and by decomposition of the surface energy budget. A daytime cooling effect from increased vegetation activity is also modeled from a set of regional weather research and forecasting (WRF) mesoscale model simulations, but with a magnitude smaller than observed, likely because the WRF model simulates a weaker ET enhancement. Our results suggest that actions to restore native grasslands in degraded areas, roughly one-third of the plateau, will both facilitate a sustainable ecological development in this region and have local climate cobenefits. More accurate simulations of the biophysical coupling between the land surface and the atmosphere are needed to help understand regional climate change over the TP, and possible larger scale feedbacks between climate in the TP and the Asian monsoon system. PMID:26170316

  2. Source and transportation of summer dust over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Jia, Rui; Liu, Yuzhi; Chen, Bin; Zhang, Zhijuan; Huang, Jianping

    2015-12-01

    Satellite observational evidences (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations, CALIPSO) have presented that the Tibetan Plateau (TP) is subject to heavy loading of dust aerosols during summer. Combining back trajectory and weather system analyses, the source and transportation of summer Tibetan dust from 2007 to 2014 were investigated. The Tibetan dust is mainly from the Taklimakan Desert and partially from the Gurbantunggut Desert and Great Indian Thar Desert. Case study indicates that the meteorological conditions together with the topography benefit the dust emission adjacent to the TP and the transport toward the plateau. When a cold advection or front developed by strong cold advection passes, dust particles are emitted into the atmosphere from the Taklimakan and Gurbantunggut deserts and then transported to the northern slope of the TP with northeasterly wind induced by the Altai and Tian Shan mountains. For the period from 2007 to 2014, the correlation coefficient of the monthly frequencies of summer dust events over the TP and cold advection passing the Taklimakan and Gurbantunggut deserts were as high as 0.68 and 0.34, respectively. Differently, although the correlation is limited, much TP dust mobilized from the Great Indian Thar Desert is associated with the passing low-pressure system activity and generally polluted by anthropogenic aerosols. The polluted dust is further transported to the southern slope of the TP by the prevailing westerly wind. Investigations on the source and transportation of summer dust over the TP provide a solid foundation of data that can be used to reveal the role of TP dust in the radiation balance, hydrological cycle, and monsoon cycle in India and East Asia.

  3. Measurements of Isotopic Composition of Vapour on the Antarctic Plateau

    NASA Astrophysics Data System (ADS)

    Casado, M.; Landais, A.; Masson-Delmotte, V.; Genthon, C.; Prie, F.; Kerstel, E.; Kassi, S.; Arnaud, L.; Steen-Larsen, H. C.; Vignon, E.

    2015-12-01

    The oldest ice core records are obtained on the East Antarctic plateau. The composition in stable isotopes of water (δ18O, δD, δ17O) permits to reconstruct the past climatic conditions over the ice sheet and also at the evaporation source. Paleothermometer accuracy relies on good knowledge of processes affecting the isotopic composition of surface snow in Polar Regions. Both simple models such as Rayleigh distillation and global atmospheric models with isotopes provide good prediction of precipitation isotopic composition in East Antarctica but post deposition processes can alter isotopic composition on site, in particular exchanges with local vapour. To quantitatively interpret the isotopic composition of water archived in ice cores, it is thus essential to study the continuum water vapour - precipitation - surface snow - buried snow. While precipitation and snow sampling are routinely performed in Antarctica, climatic conditions in Concordia, very cold (-55°C in average) and very dry (less than 1000ppmv), impose difficult conditions to measure the water vapour isotopic composition. New developments in infrared spectroscopy enable now the measurement of isotopic composition in water vapour traces (down to 20ppmv). Here we present the results of a campaign of measurement of isotopic composition in Concordia in 2014/2015. Two infrared spectrometers have been deployed or the first time on top of the East Antarctic Plateau allowing a continuous vapour measurement for a month. Comparison of the results from infrared spectroscopy with cryogenic trapping validates the relevance of the method to measure isotopic composition in dry conditions. Identification of different behaviour of isotopic composition in the water vapour associated to turbulent or stratified regime indicates a strong impact of meteorological processes in local vapour/snow interaction.

  4. Pn anisotropic tomography and dynamics under eastern Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Lei, Jianshe; Li, Yuan; Xie, Furen; Teng, Jiwen; Zhang, Guangwei; Sun, Changqing; Zha, Xiaohui

    2014-03-01

    We present a new anisotropic tomographic model of the uppermost mantle around eastern Tibet using Pn traveltime data from a newly deployed temporary seismic array and recent observation bulletins of Chinese provincial networks. Our results are generally consistent with previous results but provide new insights into the dynamics of Tibetan plateau. Prominent high-velocity (high-V) anomalies are visible under Alashan block and Qaidam and Sichuan basins, which clearly outline their tectonic margins. A distinct high-V zone representing the double-sided subduction of Indo-Eurasian plates is imaged from Lhasa block to the south of Qaidam basin. A pronounced low-velocity (low-V) zone is observed from Songpan-Ganzi block to southern Chuan-Dian diamond block, suggesting the existence of hot material upwelling there. Crustal strong earthquakes frequently occurred around high-V anomalies or transition zones from high-V to low-V anomalies, suggesting that these earthquakes could be related to lateral heterogeneities in the mantle. The Pn fast direction approximately rotates around Eastern Himalayan Syntaxis, and it is tangential to the margins of Sichuan basin, suggesting that the mantle material flow of Tibetan plateau may have affected east China. In the Yunnan region to the south of 26°N, the Pn fast direction is different from SKS splitting results, indicating that the mantle lithosphere could be mechanically decoupled at certain depth below the uppermost mantle, which might be attributable to the subduction of Indian (or Burma) slab. Although the correlation between anisotropy and velocity is complicated, anisotropy strength could be associated with the pattern of velocity anomalies in the region.

  5. Evaporative cooling over the Tibetan Plateau induced by vegetation growth

    PubMed Central

    Shen, Miaogen; Piao, Shilong; Jeong, Su-Jong; Zhou, Liming; Zeng, Zhenzhong; Ciais, Philippe; Chen, Deliang; Huang, Mengtian; Jin, Chun-Sil; Li, Laurent Z. X.; Li, Yue; Myneni, Ranga B.; Yang, Kun; Zhang, Gengxin; Zhang, Yangjian; Yao, Tandong

    2015-01-01

    In the Arctic, climate warming enhances vegetation activity by extending the length of the growing season and intensifying maximum rates of productivity. In turn, increased vegetation productivity reduces albedo, which causes a positive feedback on temperature. Over the Tibetan Plateau (TP), regional vegetation greening has also been observed in response to recent warming. Here, we show that in contrast to arctic regions, increased growing season vegetation activity over the TP may have attenuated surface warming. This negative feedback on growing season vegetation temperature is attributed to enhanced evapotranspiration (ET). The extra energy available at the surface, which results from lower albedo, is efficiently dissipated by evaporative cooling. The net effect is a decrease in daily maximum temperature and the diurnal temperature range, which is supported by statistical analyses of in situ observations and by decomposition of the surface energy budget. A daytime cooling effect from increased vegetation activity is also modeled from a set of regional weather research and forecasting (WRF) mesoscale model simulations, but with a magnitude smaller than observed, likely because the WRF model simulates a weaker ET enhancement. Our results suggest that actions to restore native grasslands in degraded areas, roughly one-third of the plateau, will both facilitate a sustainable ecological development in this region and have local climate cobenefits. More accurate simulations of the biophysical coupling between the land surface and the atmosphere are needed to help understand regional climate change over the TP, and possible larger scale feedbacks between climate in the TP and the Asian monsoon system. PMID:26170316

  6. Crustal structure north of Falkland Plateau offshore Argentina

    NASA Astrophysics Data System (ADS)

    Becker, Katharina; Schnabel, Michael; Franke, Dieter

    2010-05-01

    The passive continental margin offshore Argentina has been investigated by numerous geophysical surveys conducted by the Federal Institute for Geoscience and Natural Resources. In this study we focus on the area located north of Falkland Plateau. There, the passive margin forms the transition between the sheared margin of the Falkland Plateau and the volcanic passive margin of southern Argentina. This study aims at achieving a more detailed image of the crustal structure along the continent-ocean transition. Also we want to decipher the influence of the plume (Tristan da Cunha) on the evolution of the continental margin. The seismic data were acquired during a marine geophysical survey in 2004 and edited with an improved processing sequence. The imaging involves the application of Prestack Depth Migration, which gives information about depth and interval velocities of the reflectors. In addition we combine our seismic section with information from magnetic and gravimetric measurements. In this study we present preliminary results. A first section gives insight in the structure of the crust along the continent ocean boundary. Landwards there is no clear evidence of extension, which can be inferred from graben structures. In the transition zone the breakup unconformity is tilted seawards. In this part it is covered by a sedimentary drift body, which reaches a maximum thickness of 4km. The drift body can be divided into several units. In the east the oceanic basement is highly dissected by faults. The sedimentary succession overlying the oceanic basement reaches a maximum thickness of 4km. Further processing will reveal more details about the upper crustal structure along the margin. In the future we want to investigate the structure of the lower crust based on refraction seismic measurements.

  7. ML shear wave velocity tomography for the Iranian Plateau

    NASA Astrophysics Data System (ADS)

    Maheri-Peyrov, Mehdi; Ghods, Abdolreza; Abbasi, Madjid; Bergman, Eric; Sobouti, Farhad

    2016-04-01

    Iranian Plateau reflects several different tectonic styles of collision, and large-scale strike-slip faults. We calculate a high-resolution 2-D ML shear velocity map for the Iranian Plateau to detect lateral crustal thickness changes associated with different tectonic boundaries. The ML velocity is very sensitive to strong lateral variations of crustal thickness and varies between the velocity of Lg and Sn phases. Our data set consists of 65 795 ML amplitude velocity measurements from 2531 precisely relocated events recorded by Iranian networks in the period 1996-2014. Using a constrained least-squares inversion scheme, we inverted the ML velocities for a 2-D shear velocity map of Iran. Our results show that the Zagros and South Caspian Basin (SCB) have shear wave velocities close to the Sn phase, and are thus Lg-blocking regions. High velocities in the High Zagros and the Simply Folded Belt imply significant crustal undulations within these zones. We note that in the central and south Zagros, the velocity border between the Zagros and central Iran is not coincident with the Zagros suture line that marks underthrusting of the Arabian plate beneath central Iran. The low plains of Gilan and Gorgan to the south of the Caspian Sea show high shear velocities similar to the SCB, implying that they are either underlain by an oceanic type crust or a transitional crust with a strong lateral crustal thickness gradient. The Lut block is an Lg-passing block implying that it is not surrounded by any sudden crustal thickness changes along its borders with central Iran. In the Alborz, NW Iran, Kopeh-Dagh, Binalud and most of the central Iran, low shear velocity near the Lg velocity is attributed to smooth or minor Moho undulations within these regions.

  8. The chromium in timberline forests in the eastern Tibetan Plateau.

    PubMed

    Luo, Ji; Tang, Ronggui; She, Jia; Chen, Youchao; Gong, Yiwen; Zhou, Jun; Yu, Dong

    2013-10-01

    In order to study the regional distribution, trait and possible source of chromium in the eastern Tibetan Plateau, we collected samples of xylem, bark, leaves and twigs in two parallel northwest-southeast belt transects (TA and TB) from the Hengduan Mountains. According to the Cr mean concentration, organ/tissue was split into two groups: the high-level organ/tissue (twigs: 1.476 mg kg(-1)) and the low-level organ/tissue (bark: 0.413 mg kg(-1), leaves: 0.340 mg kg(-1) and xylem: 0.194 mg kg(-1)). The mean Cr concentrations of twigs and leaves in TB samples were higher than those in the TA samples, and the mean Cr concentration in both sites gradually reduced from southeast to northwest. Both the southeasterly and southwesterly monsoons could be significant, influential factors in this connection. The top three mean Cr concentrations were S7, S1 and S8, which were closer to the developed city. Mean Cr concentrations in S3, S4 and S5, (remote, high mountains) were relatively low. The high mountains acting as a barrier to the monsoon and the distance from the big city may play important roles in the distribution of Chromium. Furthermore, the relationship between the mean Cr concentration and precipitation, timberline trees as bio-monitors of chromium pollution in polluted areas and the possible source of Cr in the eastern Tibetan Plateau are also discussed. This study may provide reliable proof of Cr contamination processes, and so help in future to prevent further Cr pollution, and also be helpful in understanding the important function of forest ecosystems in relation to atmospheric pollution and global change. To better understand the characteristics of temporal and spatial distribution of Cr concentration, we found that tree ring, fine roots and soil samples are good choices. PMID:24056779

  9. Deconstructing the Liouvillian approach to the quantum Hall plateau transition

    NASA Astrophysics Data System (ADS)

    Oganesyan, Vadim; Chalker, J. T.; Sondhi, S. L.

    2003-07-01

    We examine the Liouvillian approach to the quantum Hall plateau transition, as introduced recently by Sinova, Meden, and Girvin [Phys. Rev. B 62, 2008 (2000)] and developed by Moore, Zee, and Sinova [Phys. Rev. Lett. 87, 046801 (2001)]. We show that, despite appearances to the contrary, the Liouvillian approach is not specific to the quantum mechanics of particles moving in a single Landau level: we formulate it for a general disordered single-particle Hamiltonian. We next examine the relationship between Liouvillian perturbation theory and conventional calculations of disorder-averaged products of Green functions and show that each term in Liouvillian perturbation theory corresponds to a specific contribution to the two-particle Green function. As a consequence, any Liouvillian approximation scheme may be reexpressed in the language of Green functions. We illustrate these ideas by applying Liouvillian methods (including their extension to NL>1 Liouvillian flavors) to random matrix ensembles, using numerical calculations for small integer NL and an analytical analysis for large NL. We find that the behavior at NL>1 is different in qualitative ways from that at NL=1. In particular, the NL=∞ limit expressed using Green functions generates a pathological approximation, in which two-particle correlation functions fail to factorize correctly at large separations of their energy, and exhibit spurious singularities inside the band of random matrix energy levels. We also consider the large-NL treatment of the quantum Hall plateau transition, showing that the same undesirable features are present there, too. We suggest that failings of this kind are likely to be generic in Liouvillian approximation schemes.

  10. Ecosystem Carbon Storage in Alpine Grassland on the Qinghai Plateau.

    PubMed

    Liu, Shuli; Zhang, Fawei; Du, Yangong; Guo, Xiaowei; Lin, Li; Li, Yikang; Li, Qian; Cao, Guangmin

    2016-01-01

    The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 and 2012. Our results revealed three key findings. (1) Total biomass carbon density ranged from 0.04 for alpine steppe to 2.80 kg C m-2 for alpine meadow. Median soil organic carbon (SOC) density was estimated to be 16.43 kg C m-2 in alpine grassland. Total ecosystem carbon density varied across sites and grassland types, from 1.95 to 28.56 kg C m-2. (2) Based on the median estimate, the total carbon storage of alpine grassland on the Qinghai Plateau was 5.14 Pg, of which 94% (4.85 Pg) was soil organic carbon. (3) Overall, we found that ecosystem carbon density was affected by both climate and grazing, but to different extents. Temperature and precipitation interaction significantly affected AGB carbon density in winter pasture, BGB carbon density in alpine meadow, and SOC density in alpine steppe. On the other hand, grazing intensity affected AGB carbon density in summer pasture, SOC density in alpine meadow and ecosystem carbon density in alpine grassland. Our results indicate that grazing intensity was the primary contributing factor controlling carbon storage at the sites tested and should be the primary consideration when accurately estimating the carbon storage in alpine grassland. PMID:27494253

  11. New constraints on Neogene uplift of the northern Colorado Plateau

    NASA Astrophysics Data System (ADS)

    Van Wijk, J. W.; Raschilla, R.

    2013-12-01

    The Late Cretaceous Uinta Basin is located in northeastern Utah within the northern most portion of the Colorado Plateau. The basin's uplift and subsidence history and thermal evolution have impacted the maturity of source beds in the Parachute Creek Member of the Green River Formation. Using measured data of the petroleum system of the Uinta Basin, we were able to constrain timing and amplitude of uplift of the northern Colorado Plateau. We used sixty wells in a basin modeling study of the Uinta Basin's thermal structure, tectonic history and petroleum system. The wells reached into basement, and four wells provided vitrinite reflectance measurements. Vitrinite reflectance is a measurement of the percentage of reflected light from a polished vitrinite sample. The percentage of reflected light is related to the temperature conditions the sample experienced during burial, and vitrinite reflectance is a maturity indicator that covers a broad temperature range from diagenesis through the latest stages of catagenesis and records the maximum temperature a rock experiences during its burial history All models were calibrated to measured data, including vitrinite reflectance and transformation ratios from Rock-Eval pyrolysis. The models predict that the heat flow ranges from 65 mW/m2 to 45 mW/m2 from south to north in the study area. Additionally, model calibration provides a means for estimating the amount of uplift and erosion in the Uinta Basin. Uplift predicted for the Uinta Basin ranges from ~2050 m to ~2200 m and started in the Late Miocene. Our models also predicted the maturity of the rich oil shales of the Parachute Creek Member.

  12. Ecosystem Carbon Storage in Alpine Grassland on the Qinghai Plateau

    PubMed Central

    Liu, Shuli; Zhang, Fawei; Du, Yangong; Guo, Xiaowei; Lin, Li; Li, Yikang; Li, Qian; Cao, Guangmin

    2016-01-01

    The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 and 2012. Our results revealed three key findings. (1) Total biomass carbon density ranged from 0.04 for alpine steppe to 2.80 kg C m-2 for alpine meadow. Median soil organic carbon (SOC) density was estimated to be 16.43 kg C m-2 in alpine grassland. Total ecosystem carbon density varied across sites and grassland types, from 1.95 to 28.56 kg C m-2. (2) Based on the median estimate, the total carbon storage of alpine grassland on the Qinghai Plateau was 5.14 Pg, of which 94% (4.85 Pg) was soil organic carbon. (3) Overall, we found that ecosystem carbon density was affected by both climate and grazing, but to different extents. Temperature and precipitation interaction significantly affected AGB carbon density in winter pasture, BGB carbon density in alpine meadow, and SOC density in alpine steppe. On the other hand, grazing intensity affected AGB carbon density in summer pasture, SOC density in alpine meadow and ecosystem carbon density in alpine grassland. Our results indicate that grazing intensity was the primary contributing factor controlling carbon storage at the sites tested and should be the primary consideration when accurately estimating the carbon storage in alpine grassland. PMID:27494253

  13. Population and Star Formation Histories from the Outer Limits Survey

    NASA Astrophysics Data System (ADS)

    Brondel, Brian Joseph; Saha, Abhijit; Olszewski, Edward

    2015-08-01

    The Outer Limits Survey (OLS) is a deep survey of selected fields in the outlying areas of the Magellanic Clouds based on the MOSAIC-II instrument on the Blanco 4-meter Telescope at CTIO. OLS is designed to probe the outer disk and halo structures of Magellanic System. The survey comprises ~50 fields obtained in Landolt R, I and Washington C, M and DDO51 filters, extending to a depth of about 24th magnitude in I. While qualitative examination of the resulting data has yielded interesting published results, we report here on quantitative analysis through matching of Hess diagrams to theoretical isochrones. We present analysis based on techniques developed by Dolphin (e.g., 2002, MNRAS, 332, 91) for fields observed by OLS. Our results broadly match those found by qualitative examination of the CMDs, but interesting details emerge from isochrone fitting.

  14. Outer Shock Interaction in Young Core-Collapse SNRs

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Joon

    2014-01-01

    Studying the environments in which core-collapse supernovae (SNe) explode and then subsequently evolve is essential to establish the nature of the mass loss and the explosion of the progenitor star. The spatial structure of the outer shock in young core-collapse SNRs provides an opportunity to study the nature of the medium into which the remnant has been expanding. We present our X-ray study of the outer shocks in young core-collapse SNRs in our Galaxy. For Cas A and G292.0+1.8, we find that both remnants have been likely interacting with dense red supergiant winds. For other remnants with bright thermal X-ray emission from the shell, we suggest that they are interacting with pre-existing circumstellar structure. We discuss the nature of the winds and the progenitor stars.

  15. The carbon budget in the outer solar nebula

    SciTech Connect

    Simonelli, D.P.; Pollack, J.B.; Mckay, C.P.; Reynolds, R.T.; Summers, A.L. )

    1989-11-01

    The compositional contrast between the giant-planet satellites and the significantly rockier Pluto/Charon system is indicative of different formation mechanisms; cosmic abundance calculations, in conjunction with an assumption of the Pluto/Charon system's direct formation from solar nebula condensates, strongly suggest that most of the carbon in the outer solar nebula was in CO form, in keeping with both the inheritance from the dense molecular clouds in the interstellar medium, and/or the Lewis and Prinn (1980) kinetic-inhibition model of solar nebula chemistry. Laboratory studies of carbonaceous chondrites and Comet Halley flyby studies suggest that condensed organic material, rather than elemental carbon, is the most likely candidate for the small percentage of the carbon-bearing solid in the outer solar nebula. 71 refs.

  16. Cloudy intergalactic accretion flows in the outer discs of galaxies

    NASA Astrophysics Data System (ADS)

    Sánchez-Salcedo, F. J.; Santillán, A.; Franco, J.

    2007-02-01

    High-resolution two-dimensional magnetohydrodynamical simulations have been carried out to investigate the role of continuing infall of clumpy gas as a driver of turbulence in extended H I galactic discs. We have compared the responses of isothermal gas discs with sound speeds 4 and 8 km/s to infalling, condensed clouds. For mass accretion rates of ˜0.6 M⊙ yr -1, the turbulent motions in the outer disc become slightly faster than transonic. We suggest that the rain of compact high velocity clouds on the disc not only can fuel the Milky Way with fresh material but is a potential source of random motions in outer regions of H I discs.

  17. Progressive outer retinal necrosis-like retinitis in immunocompetent hosts.

    PubMed

    Chawla, Rohan; Tripathy, Koushik; Gogia, Varun; Venkatesh, Pradeep

    2016-01-01

    We describe two young immunocompetent women presenting with bilateral retinitis with outer retinal necrosis involving posterior pole with centrifugal spread and multifocal lesions simulating progressive outer retinal necrosis (PORN) like retinitis. Serology was negative for HIV and CD4 counts were normal; however, both women were on oral steroids at presentation for suspected autoimmune chorioretinitis. The retinitis in both eyes responded well to oral valaciclovir therapy. However, the eye with the more fulminant involvement developed retinal detachment with a loss of vision. Retinal atrophy was seen in the less involved eye with preservation of vision. Through these cases, we aim to describe a unique evolution of PORN-like retinitis in immunocompetent women, which was probably aggravated by a short-term immunosuppression secondary to oral steroids. PMID:27511757

  18. Ultraviolet Spectrograph Concepts for the Outer Planet Flagship Mission

    NASA Astrophysics Data System (ADS)

    Retherford, Kurt D.; Stern, A.; Slater, D. C.; Gladstone, R.; Davis, M. W.; Parker, J. W.; Steffl, A. J.; Greathouse, T. K.; Cunningham, N. J.; Spencer, J. R.

    2008-09-01

    SwRI's Alice line of ultraviolet spectrographs (UVS) is founded on a lightweight, low power, and highly capable and versatile instrument design. With generally small changes in detector photocathode, detector pixel size, slit size and shape, optical coatings, pinhole aperture implementations, and other minor tweaks we've found a wide variety of applications for the Alice design, to date, at comets (Rosetta/Alice), Pluto (New Horizons/Alice), Luna (LRO/LAMP), and Jupiter (Juno/UVS). The SwRI UVS heritage includes very broad experience and strong performance to date on the Rosetta (Phase E; successful Mars flyby), New Horizons (Phase E; successful Jupiter flyby), LRO (Phase D; mated to the spacecraft), and Juno (Phase C) missions. Alice's high capability, low resource requirements, and our experience with Juno-based radiation environment and NH-based outer solar system environment requirements make this UVS a good choice for the Outer Planet Flagship mission concepts.

  19. Strategy for exploration of the outer planets: 1986-1996

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Over the past decade COMPLEX has published three strategy reports which, taken together, encompass the entire planetary system and recommend a coherent program of planetary exploration. The highest priority for outer planet exploration during the next decade is intensive study of Saturn (the planet, satellites, rings, and magnetosphere) as a system. The Committee additionally recommends that NASA engage in the following supporting activities: increased support of laboratory and theoretical studies; pursuit of earth-based and earth-orbital observations; commitment to continued operation of productive spacecraft; implementation of the instrument development plan as appropriate for the outer solar system; studies of deep atmospheric probes; development of penetrators or other hard landers; development of radiation-hardened spacecraft; and development of low-thrust propulsion systems. Longer-term objectives include exploration and intensive study of: the Uranus and Neptune systems; planetology of the Galilean satellites and Titan; and the inner Jovian system.

  20. High Power Electric Propulsion for Outer Planet Missions

    NASA Technical Reports Server (NTRS)

    Donahue, Benjamin B.

    2003-01-01

    Focused technology trade studies for Nuclear Electric Propulsion vehicle concepts for outer planet missions are presented; representative mission, vehicle and technology characterizations illustrate samples of work done under the NASA Marshall Space Flight Center-Boeing-SAIC In-Space Technology Assessment (ISTA) contract. An objective of ISTA is to identify and present sound technical and programtic options for the formulation and implementation of advanced electric and chemical propulsion solar system exploration missions. Investigations to date include a variety of outer planet destinations, trip times, science payload allotments, orbital capture techniques, all conducted to illustrate how advanced technology would maximize mission benefits. Architecture wide optimizations that facilitate good propulsion technology investments for advanced electric and chemical propulsion systems were conducted, including those relevant to the nuclear system initiative. Representative analyses of vehicles utilizing fission reactors with advanced power generation, Conversion, processing and electric propulsion systems, which would enable scientifically rich robotic exploration missions, are presented.

  1. Leaf seal for inner and outer casings of a turbine

    DOEpatents

    Schroder, Mark Stewart; Leach, David

    2002-01-01

    A plurality of arcuate, circumferentially extending leaf seal segments form an annular seal spanning between annular sealing surfaces of inner and outer casings of a turbine. The ends of the adjoining seal segments have circumferential gaps to enable circumferential expansion and contraction of the segments. The end of a first segment includes a tab projecting into a recess of a second end of a second segment. Edges of the tab seal against the sealing surfaces of the inner and outer casings have a narrow clearance with opposed edges of the recess. An overlying cover plate spans the joint. Leakage flow is maintained at a minimum because of the reduced gap between the radially spaced edges of the tab and recess, while the seal segments retain the capacity to expand and contract circumferentially.

  2. Heavy ions in the outer Kronian magnetosphere. [Saturn

    NASA Technical Reports Server (NTRS)

    Eviatar, A.; Mcnutt, R. L., Jr.; Sullivan, J. D.; Siscoe, G. L.

    1983-01-01

    The possible sources of the cold plasma observed in the outer magnetosphere of Saturn are analyzed. On the basis of the O(+)-H charge exchange species-specific loss mechanism, as well as abundance and rate considerations, it is concluded that the dominant heavy ion populating the equatorial outer magnetosphere is that of atomic nitrogen. Possible sources of hot plasma are also discussed, as are the inhibition of corotation by mass loading and the radial variation of composition. It is found that the observed deviations from corotation and current mass loading estimates indicate either a somewhat higher ionospheric conductance than is implied by the UVS and RSS measurements, or an overestimate of mass loading. It is suggested that the plasma gap observed by Voyager 1 outbound may be associated with a composition change.

  3. Theoretical studies of volatile processes in the outer solar system

    NASA Technical Reports Server (NTRS)

    Lunine, Jonathan I.

    1991-01-01

    Four studies of volatile processes in the outer solar system are discussed. Researchers suggest that the convective and conductive regions of Triton's atmosphere join at the tropopause near 10 km. A model of volatile transport on Triton's surface was constructed that predicts that Triton's surface north of 15 degrees north latitude is experiencing deposition of nitrogen frosts, as are the bright portions of the south polar cap near the equator. Also discussed are numerical models of the evolution of Titan's surface and atmosphere. Results of a study of the rheology of ammonia-water liquids were applied to the icy satellites of the outer solar system. Finally, the researchers examined the frictional heating, sublimation, and re-condensation of grains free-falling into the solar nebula from a surrounding interstellar cloud. The sublimation model includes the effect of various volatile species and accounts for the poor radiating properties of small grains using Mie theory.

  4. Dust Hazard Management in the Outer Solar System

    NASA Technical Reports Server (NTRS)

    Seal, David A.

    2012-01-01

    Most robotic missions to the outer solar system must grapple with the hazards posed by the dusty rings of the gas giants. Early assessments of these hazards led simply to ring avoidance due to insufficient data and high uncertainties on the dust population present in such rings. Recent approaches, principal among them the Cassini dust hazard management strategy, provide useful results from detailed modeling of spacecraft vulnerabilities and dust hazard regions, which along with the range of mission trajectories are used to to assess the risks posed by each passage through a zone of potential hazard. This paper shows the general approach used to implement the analysis for Cassini, with recommendations for future outer planet missions.

  5. Rotational instability in the outer region of protoplanetary disks

    SciTech Connect

    Ono, Tomohiro; Nomura, Hideko; Takeuchi, Taku

    2014-05-20

    We analytically calculate the marginally stable surface density profile for the rotational instability of protoplanetary disks. The derived profile can be utilized for considering the region in a rotating disk where radial pressure gradient force is comparable to the gravitational force, such as an inner edge, steep gaps or bumps, and an outer region of the disk. In this paper, we particularly focus on the rotational instability in the outer region of disks. We find that a protoplanetary disk with a surface density profile of similarity solution becomes rotationally unstable at a certain radius, depending on its temperature profile and a mass of the central star. If the temperature is relatively low and the mass of the central star is high, disks have rotationally stable similarity profiles. Otherwise, deviation from the similarity profiles of surface density could be observable, using facilities with high sensitivity, such as ALMA.

  6. Transients in the outer heliosphere and interstellar medium.

    NASA Astrophysics Data System (ADS)

    Richardson, J. D.; Liu, Y.

    2015-12-01

    Transients such as ICMEs and CIRs have sources at the Sun and propagate and evolve through the heliosphere and beyond. ICMEs interact to form large structures called merged interction regions (MIRs) which dominate plasma dynamics in the outer heliosphere near and after solar maximum. The structures produce factor of 10 changes in the solar wind dynmic pressure which can propagate through the heliosheath and drive shocks in the local interstellar medium. We discuss the evolution of these MIRs in the outer heliosphere and heliosheath and show the effects they have in the LISM. These effects include the production of weak shocks which affect the pitch angle distributions of galactic cosmic rays and generate plasma wave emissions. CIRs can also merge and form large structures which have similar effects in the LISM and we show the evolution of these features.

  7. Outer Space Medicine and Relevant Ongoing Biomedical Research

    PubMed Central

    Douglas, William R.

    1979-01-01

    An update of outer space medicine is given emphasizing main areas such as cardiopulmonary responses, vestibular functions, physiology, weightlessness, ecosystems, and radiation. A prospective view is also presented on the medical problems resulting from various hazards of outer space and planetary missions. Although an outgrowth of aviation and environmental medicine, this relatively new, special branch of medicine is currently undergoing an unprecedented rise as a vital modern specialty. The aims of the United States, Russia, and the nations of Europe in space research are shown to be in accord in learning how to live and work in space when confronted with the unique factors of zero gravity, cosmic radiation, and magnetic variations. PMID:439154

  8. Mission building blocks for outer solar system exploration.

    NASA Technical Reports Server (NTRS)

    Herman, D.; Tarver, P.; Moore, J.

    1973-01-01

    Description of the technological building blocks required for exploring the outer planets with maximum scientific yields under stringent resource constraints. Two generic spacecraft types are considered: the Mariner and the Pioneer. Following a discussion of the outer planet mission constraints, the evolutionary development of spacecraft, probes, and propulsion building blocks is presented. Then, program genealogies are shown for Pioneer and Mariner missions and advanced propulsion systems to illustrate the soundness of a program based on spacecraft modification rather than on the development of new spacecraft for each mission. It is argued that, for minimum costs, technological advancement should occur in an evolutionary manner from mission to mission. While this strategy is likely to result in compromises on specific missions, the realization of the overall objectives calls for an advance commitment to the entire mission series.

  9. Homesteading and the creation of property rights in outer space

    NASA Astrophysics Data System (ADS)

    Scheraga, Joel D.

    1986-08-01

    The rapid proliferation of space travel has made the colonization of space and the exploitation of its scarce resources imminent. The development of scarce resources in space has raised serious legal, political and economic questions that must soon be resolved if countries are to coexist peacefully in outer space. This paper examines the problem of defining property rights in outer space. Private property does not yet exist in space. This failure to establish property rights is critical because the scarcity of resources in the absence of ownership will inevitably lead to problems of congestion, inefficiency, and socially undesirable outcomes. A program of homesteading, combined with a competitive bidding system, is presented as an efficient and equitable means of distributing resources in space. The international debate over alternative schemes for allocating resources in space provides an opportunity for students to see the interaction of diverse but related disciplines in the liberal arts.

  10. Mitochondrial outer-membrane permeabilization and remodelling in apoptosis.

    PubMed

    Jourdain, Alexis; Martinou, Jean-Claude

    2009-10-01

    Many human pathologies are associated with defects in mitochondria such as diabetes, neurodegenerative diseases or cancer. This tiny organelle is involved in a plethora of processes in mammalian cells, including energy production, lipid metabolism and cell death. In the so-called intrinsic apoptotic pathway, the outer mitochondrial membrane (MOM) is premeabilized by the pro-apoptotic Bcl-2 members Bax and Bak, allowing the release of apoptogenic factors such as cytochrome c from the inter-membrane space into the cytosol. At the same time, mitochondria fragment in response to Drp-1 activation suggesting that mitochondrial fission could play a role in mitochondrial outer-membrane permeabilization (MOMP). In this review, we will discuss the link that could exist between mitochondrial fission and fusion machinery, Bcl-2 family members and MOMP. PMID:19439192

  11. Towards Simulations of Outer Membrane Proteins in Lipopolysaccharide Membranes

    SciTech Connect

    Soares, Thereza A.; Straatsma, TP

    2007-12-26

    Biomolecular simulation derived properties of LPS membranes that impact the structural and internal dynamics of transmembrane proteins are shown to exhibit good agreement with available experimental data within the time scale simulated, chosen force field and simulation conditions. The molecular model used offers an accurate representation of the LPS layer, including the high asymmetry and low fluidity characteristics of outer membranes. This contribution describes the data intensive analysis of the large molecular time trajectories generated for these systems using massively parallel computing resources.

  12. Progressive Outer Retinal Necrosis and Immunosuppressive Therapy in Myasthenia Gravis

    PubMed Central

    Coisy, Solène; Ebran, Jean-Marc; Milea, Dan

    2014-01-01

    Introduction Progressive outer retinal necrosis (PORN) is a rare but devastating infectious retinitis associated with varicella zoster virus (VZV) and responsible for severe visual loss. Case Report A 59-year-old man treated for generalized myasthenia with oral azathioprine and prednisone presented with severe unilateral necrotizing retinitis. Polymerase chain reaction of the aqueous and vitreous humors was diagnostic for VZV PORN. Conclusion VZV PORN is a severe potential ocular complication of immunosuppression, prompting urgent diagnosis and appropriate treatment. PMID:24926266

  13. CORNER OF SUBPILE ROOM: NORTH AND EAST SIDES. STEEL OUTER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CORNER OF SUBPILE ROOM: NORTH AND EAST SIDES. STEEL OUTER SHELL HAS BEEN AFFIXED. SIGN SAYS "HERRICK IRON WORKS STEEL, OAKLAND, CALIFORNIA." NOTE CONDUIT FOR FUTURE INSTRUMENTATION. TOP OF STEEL CASE WILL BE LEVEL WITH BASEMENT CEILING. CAMERA FACES SOUTHEAST. INL NEGATIVE NO. 734. Unknown Photographer, 10/6/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  14. Immunogenicity of Pasteurella multocida and Mannheimia haemolytica outer membrane vesicles

    PubMed Central

    Roier, Sandro; Fenninger, Judith C.; Leitner, Deborah R.; Rechberger, Gerald N.; Reidl, Joachim; Schild, Stefan

    2013-01-01

    Pasteurella multocida is able to cause disease in humans and in a wide range of animal hosts, including fowl cholera in birds, atrophic rhinitis in pigs, and snuffles in rabbits. Together with Mannheimia haemolytica, P. multocida also represents a major bacterial causative agent of bovine respiratory disease (BRD), which is one of the most important causes for economic losses for the cattle backgrounding and feedlot industry. Commercially available vaccines only partially prevent infections caused by P. multocida and M. haemolytica. Thus, this study characterized the immunogenicity of P. multocida and M. haemolytica outer membrane vesicles (OMVs) upon intranasal immunization of BALB/c mice. Enzyme-linked immunosorbent assays (ELISA) revealed that OMVs derived from P. multocida or M. haemolytica are able to induce robust humoral and mucosal immune responses against the respective donor strain. In addition, also significant cross-immunogenic potential was observed for both OMV types. Colonization studies showed that a potential protective immune response against P. multocida is not only achieved by immunization with P. multocida OMVs, but also by immunization with OMVs derived from M. haemolytica. Immunoblot and immunoprecipitation analyses demonstrated that M. haemolytica OMVs induce a more complex immune response compared to P. multocida OMVs. The outer membrane proteins OmpA, OmpH, and P6 were identified as the three major immunogenic proteins of P. multocida OMVs. Amongst others, the serotype 1-specific antigen, an uncharacterized outer membrane protein, as well as the outer membrane proteins P2 and OmpA were found to be the most important antigens of M. haemolytica OMVs. These findings are useful for the future development of broad-spectrum OMV based vaccines against BRD and other infections caused by P. multocida or M. haemolytica. PMID:23731905

  15. Atmospheres and ionospheres of the outer planets and their satellites

    NASA Technical Reports Server (NTRS)

    Atreya, Sushil K.

    1986-01-01

    Essential aspects of physical and chemical processes in the atmospheres and ionospheres of the outer planets are examined in an introductory overview of current knowledge, intended both for graduate students of planetary science and for practicing scientists. Chapters are devoted to bulk atmospheric compositions, thermal structures, cloud structures, vertical mixing, photochemistry, the ionospheres, and the satellites. Measurement data are compiled in tables, and extensive graphs and diagrams are provided.

  16. WHICH RADIAL VELOCITY EXOPLANETS HAVE UNDETECTED OUTER COMPANIONS?

    SciTech Connect

    Rodigas, Timothy J.; Hinz, Philip M.

    2009-09-01

    The observed radial velocity (RV) eccentricity distribution for extrasolar planets in single-planet systems shows that a significant fraction of planets are eccentric (e > 0.1). However, an RV planet's eccentricity, which comes from the Keplerian fitting, can be biased by low signal-to-noise ratio and poor sampling. Here, we investigate the effects on eccentricity produced by undetected outer companions. We have carried out Monte Carlo simulations of mock RV data to understand this effect and predict its impact on the observed distribution. We first quantify the statistical bias of known RV planets' eccentricities produced by undetected zero-eccentricity wide-separation companions and show that this effect alone cannot explain the observed distribution. We then modify the simulations to consist of two populations, one of zero-eccentricity planets in double-planet systems and the other of single planets drawn from an eccentric distribution. Our simulations show that a good fit to the observed distribution is obtained with 45% zero-eccentricity double planets and 55% single eccentric planets. Assuming that our two simulated populations of planets are a good approximation for the true RV population, matching the observed distribution allows us to determine the probability that a known RV planet's orbital eccentricity has been biased by an undetected wide-separation companion. Averaged over eccentricity we calculate this probability to be {approx}4%, suggesting that a small fraction of systems may have a yet to be discovered outer companion. Our simulations show that moderately eccentric planets, with 0.1 < e < 0.3 and 0.1 < e < 0.2, have a {approx}13% and {approx}19% probability, respectively, of having an undetected outer companion. We encourage both high-contrast direct imaging and RV follow-up surveys of known RV planets with moderate eccentricities to test our predictions and look for previously undetected outer companions.

  17. Law and politics in outer space: A bibliography.

    NASA Technical Reports Server (NTRS)

    White, I. L.; Wilson, C. E.; Vosburgh, J. A.

    1972-01-01

    The materials are categorized by specific topics and by types of materials. The sources are books, articles, reports, United Nations materials, U.S. Government documents, etc. Books are listed by geographical areas, and articles are divided into what are considered to be the major space topics. Book and article sections are also divided into English and foreign language entries. A bibliographical essay introduces the literature to those unacquainted with law and politics of outer space.

  18. Planning Assembly Of Large Truss Structures In Outer Space

    NASA Technical Reports Server (NTRS)

    De Mello, Luiz S. Homem; Desai, Rajiv S.

    1992-01-01

    Report dicusses developmental algorithm used in systematic planning of sequences of operations in which large truss structures assembled in outer space. Assembly sequence represented by directed graph called "assembly graph", in which each arc represents joining of two parts or subassemblies. Algorithm generates assembly graph, working backward from state of complete assembly to initial state, in which all parts disassembled. Working backward more efficient than working forward because it avoids intermediate dead ends.

  19. Outer Retinal Structure in Best Vitelliform Macular Dystrophy

    PubMed Central

    Kay, David B.; Land, Megan E.; Cooper, Robert F.; Dubis, Adam M.; Godara, Pooja; Dubra, Alfredo; Carroll, Joseph; Stepien, Kimberly E.

    2014-01-01

    Objective To characterize outer retinal structure in Best Vitelliform Macular Dystrophy (BVMD), using spectral domain optical coherence tomography (SD-OCT) and adaptive optics scanning light ophthalmoscopy (AOSLO). Methods Four symptomatic members of a family with BVMD with known BEST1 gene mutation were recruited. Thickness of two outer retinal layers corresponding to photoreceptor inner and outer segments were measured using SD-OCT. Photoreceptor mosaic AOSLO images within and around visible lesions were obtained, and cone density was assessed in two subjects. Results Each subject was at a different stage of BVMD, with photoreceptor disruption evident by AOSLO at all stages. When comparing SD-OCT and AOSLO images from the same location, AOSLO images allowed for direct assessment of photoreceptor structure. A variable degree of retained photoreceptors was seen within all lesions. The photoreceptor mosaic immediately adjacent to visible lesions appeared contiguous and was of normal density. Fine hyperreflective structures were visualized by AOSLO, and their anatomical orientation and size are consistent with Henle fibers. Conclusions AOSLO findings indicate substantial photoreceptor structure persists within active lesions, accounting for good visual acuity in these patients. Despite previous reports of diffuse photoreceptor outer segment abnormalities in BVMD, our data reveal normal photoreceptor structure in areas adjacent to clinical lesions. Clinical Relevance This study demonstrates the utility of AOSLO for understanding the spectrum of cellular changes that occur in inherited degenerations such as BVMD. Photoreceptors are often significantly affected at various stages of inherited degenerations, and these changes may not be readily apparent with current clinical imaging instrumentation. PMID:23765342

  20. ULF waves in the outer magnetosphere of Uranus

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Lepping, R. P.

    1992-01-01

    ULF waves are ubiquitous in the terrestrial magnetosphere, and play a critical role in the physics of the magnetosphere. A search for similar waves in the Uranian magnetosphere using Voyager 2 magnetometer data reveals ULF waves in the outer magnetosphere near the magnetopause. These waves decrease in amplitude with distance from the magnetopause. In the interior of the magnetosphere the wave level is at or below the noise level of the instrument.