Science.gov

Sample records for af zone boundary

  1. 78 FR 15883 - Standard Time Zone Boundaries

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-13

    ... Office of the Secretary 49 CFR Part 71 RIN 2105-AE20 Standard Time Zone Boundaries AGENCY: Office of the... and amends the Department's standard time zone boundaries regulations to reflect changes that Congress made to the Uniform Time Act. The purpose of this update is to ensure that the Department's...

  2. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  3. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  4. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Boundary pillars and buffer zones. 3931... AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones. (a... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  5. 43 CFR 3931.100 - Boundary pillars and buffer zones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Boundary pillars and buffer zones. 3931... EXPLORATION AND LEASES Plans of Development and Exploration Plans § 3931.100 Boundary pillars and buffer zones... prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from...

  6. Gradient zone boundary control in salt gradient solar ponds

    DOEpatents

    Hull, John R.

    1984-01-01

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  7. Denuded Zones, Diffusional Creep, and Grain Boundary Sliding

    SciTech Connect

    Wadsworth, J; Ruano, O A; Sherby, O D

    2001-06-27

    The appearance of denuded zones following low stress creep in particle-containing crystalline materials is both a microstructural prediction and observation often cited as irrefutable evidence for the Nabarro-Herring mechanism of diffusional creep. The denuded zones are predicted to be at grain boundaries that are orthogonal to the direction of the applied stress. Furthermore, their dimensions should account for the accumulated plastic flow. In the present paper, the evidence for such denuded zones is critically examined. These zones have been observed during creep of magnesium, aluminum, and nickel-base alloys. The investigation casts serious doubts on the apparently compelling evidence for the link between denuded zones and diffusional creep. Specifically, denuded zones are clearly observed under conditions that are explicitly not diffusional creep. Additionally, the denuded zones are often found in directions that are not orthogonal to the applied stress. Other mechanisms that can account for the observations of denuded zones are discussed. It is proposed that grain boundary sliding accommodated by slip is the rate-controlling process in the stress range where denuded zones have been observed. It is likely that the denuded zones are created by dissolution of precipitates at grain boundaries that are simultaneously sliding and migrating during creep.

  8. Defining the Entrainment Zone in Stratocumulus-topped Boundary Layers

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Zhou, M.; Kalogiros, J. A.; Lenschow, D. H.; Dai, C.; Wang, S.

    2010-12-01

    The presence of an entrainment zone near the top of the stratocumulus-topped boundary layers has been identified by many early studies. However, the definition of the entrainment zone was rather vague. We have examined the fine vertical variations of cloud liquid water content, wind, temperature and humidity near the stratocumulus top and developed a new method to identify the entrainment zone objectively. Aircraft measurements from various field projects in stratocumulus-topped boundary layers are used, taking advantage of the fast sampling capability of many of the aircraft sensors. Because of the inhomogeneous mixing of two air masses with distinctively different thermodynamic properties, the magnitude of temperature perturbations within the entrainment zone is significantly larger than those above or below. This characteristics is used to define the upper and lower boundaries of the entrainment zone using a wavelet spectra analyses. The definition of the entrainment zone is further evaluated by the presence of a linear mixing line through mixing line analyses. Various other interfaces at the cloud top are also examined, including the cloud interface, temperature interface (inversion), and moisture interface. The heights of these interfaces are examined relative to the height of the entrainment zone. This study also systematically revealed the presence of turbulence above the local cloud top and/or above the entrainment zone. Wind shear near the cloud top is one possible source that generated local turbulence. Other potential sources of turbulence will also be discussed.

  9. 49 CFR 71.7 - Boundary line between central and mountain zones.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Boundary line between central and mountain zones... BOUNDARIES § 71.7 Boundary line between central and mountain zones. (a) Montana-North Dakota. Beginning at... upon the zone boundary line described in this section are in the mountain standard time zone,...

  10. 49 CFR 71.9 - Boundary line between mountain and Pacific zones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Boundary line between mountain and Pacific zones... BOUNDARIES § 71.9 Boundary line between mountain and Pacific zones. (a) Montana-Idaho-Oregon. From the... zone boundary line described in this section are in the mountain standard time zone....

  11. 49 CFR 71.7 - Boundary line between central and mountain zones.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Boundary line between central and mountain zones... BOUNDARIES § 71.7 Boundary line between central and mountain zones. (a) Montana-North Dakota. Beginning at... upon the zone boundary line described in this section are in the mountain standard time zone,...

  12. 49 CFR 71.7 - Boundary line between central and mountain zones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Boundary line between central and mountain zones... BOUNDARIES § 71.7 Boundary line between central and mountain zones. (a) Montana-North Dakota. Beginning at... located upon the zone boundary line described in this section are in the mountain standard time...

  13. 49 CFR 71.7 - Boundary line between central and mountain zones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Boundary line between central and mountain zones... BOUNDARIES § 71.7 Boundary line between central and mountain zones. (a) Montana-North Dakota. Beginning at... located upon the zone boundary line described in this section are in the mountain standard time...

  14. 49 CFR 71.9 - Boundary line between mountain and Pacific zones.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Boundary line between mountain and Pacific zones... BOUNDARIES § 71.9 Boundary line between mountain and Pacific zones. (a) Montana-Idaho-Oregon. From the... boundary line described in this section are in the mountain standard time zone....

  15. 49 CFR 71.7 - Boundary line between central and mountain zones.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Boundary line between central and mountain zones... BOUNDARIES § 71.7 Boundary line between central and mountain zones. (a) Montana-North Dakota. Beginning at... mountain standard time zone, except Murdo, S. Dak., which is in the central standard time zone....

  16. Measuring Transient Signals in Plate Boundary Faults Zones with Strainmeters

    NASA Astrophysics Data System (ADS)

    Hodgkinson, Kathleen; Mencin, Dave; Phillips, David; Henderson, Brent; Gottlieb, Mike; Gallaher, Warren; Johnson, Wade; Pyatt, Chad; Van Boskirk, Elizabeth; Fox, Otina; Mattioli, Glen; Meertens, Chuck

    2014-05-01

    One of the fundamental goals the U.S. National Science Foundation (NSF) funded Earthscope program was to provide a high-quality, continuous geodetic data set that would allow the scientific community to study the evolution of plate boundary zones. Of particular importance was enabling investigation of the role aseismic transient deformation plays in the release of accumulated stress. For example, to allow the comparison of the amount of strain released through Episodic Tremor and Slip (ETS) events to that released in subduction zone earthquakes or, provide the ability to geodetically illuminate the kinematics of fault creep in strike-slip fault zones. The ability to easily integrate these measurements with compatible geophysical data sets was also an essential objective. With goals such as these in mind NSF funded the Plate Boundary Observatory (PBO) to record the continuous deformation field across the western US Plate Boundary. PBO, built and operated by UNAVCO, now consists of over 1100 GPS stations, 76 co-located borehole strain and seismic sites, 6 long baseline strainmeters, Depending on the scientific questions being addressed sites may also have tiltmeter, meteorological, pore pressure and meteorological instrumentation. This presentation will focus on the transient deformation signals recorded by the PBO strainmeter network. PBO strainmeters, which excel in recording signals on the order of nanostrain over hours, have provided unprecedented temporal resolution of aseismic transients such as ETS events in the Cascadia subduction zone, creep signals along the central section of the San Andreas fault system and tsunami generated strain waves. UNAVCO is responsible not only for the ongoing operation of PBO but also the generation of data products associated with each instrument type. In this presentation we will highlight some of the transient signals these instruments have captured, outline the processing steps required to extract these signals data and

  17. 49 CFR 71.9 - Boundary line between mountain and Pacific zones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Boundary line between mountain and Pacific zones. 71.9 Section 71.9 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.9 Boundary line between mountain and Pacific zones. (a) Montana-Idaho-Oregon. From...

  18. 49 CFR 71.9 - Boundary line between mountain and Pacific zones.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Boundary line between mountain and Pacific zones. 71.9 Section 71.9 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.9 Boundary line between mountain and Pacific zones. (a) Montana-Idaho-Oregon. From...

  19. 49 CFR 71.9 - Boundary line between mountain and Pacific zones.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Boundary line between mountain and Pacific zones. 71.9 Section 71.9 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.9 Boundary line between mountain and Pacific zones. (a) Montana-Idaho-Oregon. From...

  20. MOLA Topography of the Crustal Dichotomy Boundary Zone, Mars

    NASA Technical Reports Server (NTRS)

    Frey, Herbert V.; E. H., Susan; H., James

    1998-01-01

    Mars Orbiter Laser Altimeter (MOLA) profiles frequently cross the crustal dichotomy boundary where the transition zone (TZ) between cratered highland terrain (CT) and lowland smooth plains (SP) is marked by mesas and knobby terrain. The detailed topographic character of the boundary zone is longitudinally variable, as is the geomorphology of the TZ. Some portions of the boundary are associated with an outer ring of the Utopia impact basin; MOLA topography is consistent with this. The regional character of the boundary topography is a 2-4 km step function from nearly flat SP to almost as flat CT. This rise has a regional slope of 1-2 degrees, 50-100 times that of the Cr and SP away from TZ, which suggests a significant change in crustal properties (thickness, composition or both) across the TZ. The overall topography is very similar to that at some passive continent-oceanic crustal margins on the Earth, with the seafloor allowed to adjust upward after removal of the overlying water. A possible temporal constraint on the CT/SP elevation difference comes from two MOLA profiles which pass through two large (150 km diameter) craters located at the boundary in Aeolis. The N and S rims of the more degraded crater are at the same elevation; north of the N rim the topography drops by greater than 2 km to the floor of the TZ. This crater predates the elevation offset between CT and TZ floor. The better preserved crater (Gale) has a N rim 2 km lower than its S rim, and appears to have been emplaced on a pre-existing regional slope of about I degree. Gale probably post- dates the elevation difference between CT and TZ floor. Based on the stratigraphy of the units in which these craters are found, the elevation difference appears to have been in place in the Mid to Late Noachian.

  1. Owen Fracture Zone: The Arabia-India plate boundary unveiled

    NASA Astrophysics Data System (ADS)

    Fournier, M.; Chamot-Rooke, N.; Rodriguez, M.; Huchon, P.; Petit, C.; Beslier, M. O.; Zaragosi, S.

    2011-02-01

    We surveyed the Owen Fracture Zone at the boundary between the Arabia and India plates in the NW Indian Ocean using a high-resolution multibeam echo-sounder (Owen cruise, 2009) for search of active faults. Bathymetric data reveal a previously unrecognized submarine fault scarp system running for over 800 km between the Sheba Ridge in the Gulf of Aden and the Makran subduction zone. The primary plate boundary structure is not the bathymetrically high Owen Ridge, but is instead a series of clearly delineated strike-slip fault segments separated by several releasing and restraining bends. Despite an abundant sedimentary supply by the Indus River flowing from the Himalaya, fault scarps are not obscured by recent deposits and can be followed over hundreds of kilometres, pointing to very active tectonics. The total strike-slip displacement of the fault system is 10-12 km, indicating that it has been active for the past ~ 3 to 6 Ma if its current rate of motion of 3 ± 1 mm yr- 1 has remained stable. We describe the geometry of this recent fault system, including a major pull-apart basin at the latitude 20°N, and we show that it closely follows an arc of small circle centred on the Arabia-India pole of rotation, as expected for a transform plate boundary.

  2. Grey zone simulations of the morning convective boundary layer development

    NASA Astrophysics Data System (ADS)

    Efstathiou, G. A.; Beare, R. J.; Osborne, S.; Lock, A. P.

    2016-05-01

    Numerical simulations of two cases of morning boundary layer development are conducted to investigate the impact of grid resolution on mean profiles and turbulent kinetic energy (TKE) partitioning from the large eddy simulation (LES) to the mesoscale limit. Idealized LES, using the 3-D Smagorinsky scheme, is shown to be capable of reproducing the boundary layer evolution when compared against measurements. However, increasing grid spacing results in the damping of resolved TKE and the production of superadiabatic temperature profiles in the boundary layer. Turbulence initiation is significantly delayed, exhibiting an abrupt onset at intermediate resolutions. Two approaches, the bounding of vertical diffusion coefficient and the blending of the 3-D Smagorinsky with a nonlocal 1D scheme, are used to model subgrid diffusion at grey zone resolutions. Simulations are compared against the coarse-grained fields from the validated LES results for each case. Both methods exhibit particular strengths and weaknesses, indicating the compromise that needs to be made currently in high-resolution numerical weather prediction. The blending scheme is able to reproduce the adiabatic profiles although turbulence is underestimated in favor of the parametrized heat flux, and the spin-up of TKE remains delayed. In contrast, the bounding approach gives an evolution of TKE that follows the coarse-grained LES very well, relying on the resolved motions for the nonlocal heat flux. However, bounding gives unrealistic static instability in the early morning temperature profiles (similar to the 3-D Smagorinsky scheme) because model dynamics are unable to resolve TKE when the boundary layer is too shallow compared to the grid spacing.

  3. Grain Boundary Plane Orientation Fundamental Zones and Structure-Property Relationships

    PubMed Central

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-01-01

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries. PMID:26498715

  4. Grain boundary plane orientation fundamental zones and structure-property relationships

    DOE PAGESBeta

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to themore » strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.« less

  5. Grain boundary plane orientation fundamental zones and structure-property relationships

    SciTech Connect

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.

  6. Joining the Great Plains in Space, Place, and Time: Questioning a Time Zone Boundary

    ERIC Educational Resources Information Center

    Kuper, Rob

    2011-01-01

    Standard time zone boundaries are invisible in the landscape, yet they abruptly delineate a temporal difference of one hour between two large areas located relative to one another on Earth. In most cases, standard time zone boundaries follow political ones and define areas within which daylight saving time (DST)--the seasonal advancement of…

  7. Kinematics and shear heat pattern of ductile simple shear zones with `slip boundary condition'

    NASA Astrophysics Data System (ADS)

    Mulchrone, Kieran F.; Mukherjee, Soumyajit

    2016-04-01

    Extrusion by Poiseuille flow and simple shear of hot lower crust has been deciphered from large hot orogens, and partial-slip boundary condition has been encountered in analogue models. Shear heat and velocity profiles are deduced from a simplified form of Navier-Stokes equation for simple shear together with extrusive Poiseuille flow and slip boundary condition for Newtonian viscous rheology. A higher velocity at the upper boundary of the shear zone promotes higher slip velocity at the lower boundary. The other parameters that affect the slip are viscosity and thickness of the shear zone and the resultant pressure gradient that drives extrusion. In the partial-slip case, depending on flow parameters (resultant pressure gradient, density and viscosity) and thickness of the shear zone, the velocity profiles can curve and indicate opposite shear senses. The corresponding shear heat profiles can indicate temperature maximum inside shear zones near either boundaries of the shear zone, or equidistant from them.

  8. MOLA Topographic Variations Along the Crustal Dichotomy Boundary Zone in Eastern and Western Mars

    NASA Technical Reports Server (NTRS)

    Frey, H; Sakimoto, S.; Roark, J.

    1999-01-01

    The topographic character of the martian crustal dichotomy boundary zone changes along the boundary, as does the morphological character of the boundary itself. Overall the elevation change from lowland plains to cratered uplands has the character of a step function, but the magnitude of the step and the slope of the ramp in the transition zone between the two relatively flat surfaces is different in different areas. Especially prominent is the difference between the boundaries in Deuteronilus-Ismenius Lacus and in Tempe Terra: Total relief in the transition zone in central Tempe is significantly greater than that in most of the eastern boundary zone. The correlation of topography with changing morphological character and mapped geologic units suggests that different parts of the boundary had different modification histories, and, perhaps, different origins as well.

  9. Habitable Zone Boundaries: Implications for our Solar System and Beyond

    NASA Astrophysics Data System (ADS)

    Kasting, J. F.; Kopparapu, R.; Harman, C.; Batalha, N. E.; Haqq-Misra, J. D.

    2015-12-01

    The successful completion of NASA's Kepler Mission has led to renewed interest in the definition and boundaries of the circumstellar habitable zone (HZ), where liquid water can be stable on a planet's surface. Goldblatt et al. [1] showed that the runaway greenhouse effect, which defines the inner edge of the HZ, depends critically on absorption coefficients of H2O obtained from the new HITEMP database. Kopparapu et al. [2,3] followed up on this observation by recalculating HZ boundaries using HITEMP coefficients. This caused the inner edge to move out to 0.99 AU in their (fully saturated, cloud-free) 1-D climate model. Leconte et al. [4] then used a 3-D climate model to show that the inner edge moves back in to 0.95 AU when relative humidity and clouds are taken into account. In their model, however, the upper stratosphere remained cold and dry, making it difficult to explain how Venus lost its water. But Leconte et al. only looked at surface temperatures up to ~330 K. At somewhat higher surface temperatures (350 K), our own 1-D model predicts that the stratosphere should indeed become wet [5]. Towards the outer edge of the HZ, it now appears that planets should undergo limit cycles involving global glaciation, CO2 buildup from volcanism, and CO2 drawdown from weathering [6,7]. If supplemented with volcanic H2 [8], such cycles could explain how early Mars could have been cold much of the time and yet have experienced enough warm periods to carve the observed fluvial features. Results from a new model of this process will be discussed. Refs: 1. Goldblatt, C., Robinson, T. D., Zahnle, K. J., & Crisp, D. 2013, Nature Geoscience, 6, 661 2. Kopparapu, R. K., et al. 2013, Astrophysical Journal, 765 3. ---. 2013, Astrophysical Journal, 770 4. Leconte, J., Forget, F., Charnay, B., Wordsworth, R., & Pottier, A. 2013, Nature, 504, 268 5. Kasting, J. F., Chen, H., & Kopparapu, R. K. in prep., Ap J Lett 6. Kadoya, S., & Tajika, E. 2014, Astrophysical Journal, 790 7. Menou, K

  10. Multiscale Modeling of Grain-Boundary Fracture: Cohesive Zone Models Parameterized From Atomistic Simulations

    NASA Technical Reports Server (NTRS)

    Glaessgen, Edward H.; Saether, Erik; Phillips, Dawn R.; Yamakov, Vesselin

    2006-01-01

    A multiscale modeling strategy is developed to study grain boundary fracture in polycrystalline aluminum. Atomistic simulation is used to model fundamental nanoscale deformation and fracture mechanisms and to develop a constitutive relationship for separation along a grain boundary interface. The nanoscale constitutive relationship is then parameterized within a cohesive zone model to represent variations in grain boundary properties. These variations arise from the presence of vacancies, intersticies, and other defects in addition to deviations in grain boundary angle from the baseline configuration considered in the molecular dynamics simulation. The parameterized cohesive zone models are then used to model grain boundaries within finite element analyses of aluminum polycrystals.

  11. 'True' Color Mosaic of Jupiter's Belt-Zone Boundary

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Pseudo-true color mosaic of a belt-zone boundary near Jupiter's equator. The images that make up the four quadrants of this mosaic were taken within a few minutes of each other. Galileo observes Jupiter's atmosphere in violet and near-infrared light because these wavelengths give information about composition and altitude. While these wavelengths do not allow a true-color image to be constructed (one would need red, green and blue), a pseudo-true color image can be made. Violet light (415 nanometers) is displayed in blue and near-infrared light (757 nanometers) is displayed in red. A combination of violet and near-infrared light is displayed in green. There is unique information in color images because they simultaneously show how regions of the atmosphere interact with several different wavelengths of light. Clouds that appear white reflect light equally at the different wavelengths. Concentrations of certain chemicals or types of cloud particles give a reddish tint to other areas.

    North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo.

  12. False Color Mosaic of Jupiter's Belt-Zone Boundary

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This false color mosaic shows a belt-zone boundary near Jupiter's equator. The images that make up the four quadrants of this mosaic were taken within a few minutes of each other. Light at each of Galileo's three near-infrared wavelengths is displayed here in the visible colors red, green and blue. Light at 886 nanometers, strongly absorbed by atmospheric methane and scattered from clouds high in the atmosphere, is shown in red. Light at 732 nanometers, moderately absorbed by atmospheric methane, is shown in green. Light at 757 nanometers, scattered mostly from Jupiter's lower visible cloud deck, is shown in blue. The lower cloud deck appears bluish white, while the higher layer appears pinkish. The holes in the upper layer and their relationships to features in the lower cloud deck can be studied in the lower half of the mosaic. Galileo is the first spacecraft to image different layers in Jupiter's atmosphere.

    The edge of the planet runs along the right side of the mosaic. North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 280 degrees west. The smallest resolved features are tens of kilometers in size. These images were taken on Nov. 5, 1996, at a range of 1.2 million kilometers by the solid state imaging (CCD) system aboard NASA's Galileo spacecraft.

    Launched in October 1989, Galileo entered orbit around Jupiter on Dec. 7, 1995. The spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo.

  13. False Color Mosaic of Jupiter's Belt-Zone Boundary

    NASA Technical Reports Server (NTRS)

    1997-01-01

    False-color mosaic of a belt-zone boundary near Jupiter's equator. The images that make up the four quadrants of this mosaic were taken within a few minutes of each other. Light at each of Galileo's three near-infrared wavelengths is displayed here mapped to the visible colors red, green, and blue. Light at 886 nanometers, strongly absorbed by atmospheric methane and scattered from clouds high in the atmosphere, is shown in red. Light at 732 nanometers, moderately absorbed by atmospheric methane, is shown in green. Light at 757 nanometers, scattered mostly from Jupiter's lower visible cloud deck, is shown in blue. The lower cloud deck appears bluish white, while the higher layer appears pinkish. The holes in the upper layer and their relationships to features in the lower cloud deck can be studied in the lower half of the mosaic. Galileo is the first spacecraft to image different layers in Jupiter's atmosphere.

    North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  14. The North America - South America plate boundary zone: new elements for a geodynamic model

    NASA Astrophysics Data System (ADS)

    Roest, W. R.; Pichot, T.; Patriat, M.; Westbrook, G. K.; Gutscher, M.

    2011-12-01

    The location and functioning of the North America - South America plate boundary zone remain unknown, despite significant past efforts to decipher its precise position and the associated deformation. The Barracuda Ridge and the Tiburon Rise, two major oceanic basement ridges, are situated at the western end of this diffuse plate-boundary zone, where they enter the subduction zone beneath the Lesser Antilles island arc. The deformation of these features, and the intervening sedimentary basins and their stratigraphy record the history of NoAM-SoAM motion in this area. Kinematic studies based on reconstruction of past plate motions and GPS measurements predict small convergence during the Tertiary in the western part of this boundary zone, between the Marathon and Fifteen Twenty fracture zones. However, the differences between the different models remains too large to predict the NoAM-SoAM relative motions in this area confidently, as small changes in the postions of their rotation poles have major consequences for the expected distribution of deformation, because of their proximity to the area. Recent geophysical data acquired in this region has enabled us to locate the major structural features, and to propose an improved timing of the deformation. Seismic lines confirm the transpressional tectonic regime over a zone that is about 250 km wide, between the Barracuda Trough and the Tiburon Rise. The geodynamic situation is complicated by the fact that the deformation in the area of the Tiburon Rise and the Barracuda Ridge is clearly influenced by the flexural bulge of the active subduction zone, which uplifts the western ends of both ridges and provides a distinct western boundary to the Tiburon sedimentary basin, a trough situated between them. We have attempted to distinguish the influence of both the NoAM-SoAM convergence and the subduction process. In the North Atlantic west of Iberia, an apparently similar diffuse plate boundary zone between Europe and Africa

  15. Gradient zone-boundary control in salt-gradient solar ponds

    DOEpatents

    Hull, J.R.

    1982-09-29

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  16. Finite Element Modeling of Crustal Deformation in the North American Caribbean Plate Boundary Zone

    NASA Technical Reports Server (NTRS)

    Lundgren, P.; Russo, R.

    1995-01-01

    We have developed 2-dimensional spherical shell finite element models of elastic displacement in the North American-Caribbean (NA-Ca) plate boundary zone (PBZ) in order to quantify crust and fault motions in the PBZ.

  17. Surface plasmons at the Brillouin zone boundary of an oblique lattice

    SciTech Connect

    Constant, Thomas J. Vukusic, Pete; Hibbins, Alastair P.; Sambles, J. Roy

    2015-03-02

    In periodic systems of low-symmetry, the Bragg condition for the complete interference of waves along the contour of the Brillouin zone (BZ) boundary is not generally satisfied. As a result, band-gaps do not necessarily occur at this boundary. This letter demonstrates this experimentally by recording the iso-frequency contours for surface plasmon polaritons (SPPs) supported on a diffraction grating with an underlying 2D oblique Bravias lattice. It is shown that these contours do not intersect the BZ boundary perpendicularly, as the symmetry operations of the lattice place no conditions on the surface wave interference at this boundary.

  18. The control of float zone interfaces by the use of selected boundary conditions

    NASA Technical Reports Server (NTRS)

    Foster, L. M.; Mcintosh, J.

    1983-01-01

    The main goal of the float zone crystal growth project of NASA's Materials Processing in Space Program is to thoroughly understand the molten zone/freezing crystal system and all the mechanisms that govern this system. The surface boundary conditions required to give flat float zone solid melt interfaces were studied and computed. The results provide float zone furnace designers with better methods for controlling solid melt interface shapes and for computing thermal profiles and gradients. Documentation and a user's guide were provided for the computer software.

  19. Ductile shear zones related to crustal shortening and domain boundary evolution in the central Fennoscandian Shield

    NASA Astrophysics Data System (ADS)

    HöGdahl, Karin; SjöStröM, HâKan; Bergman, Stefan

    2009-02-01

    The Paleoproterozoic part of the Fennoscandian Shield is composed of crustal components formed in different tectonic settings and generally separated by well-defined shear zone systems. An anomalous transitional boundary has been investigated by integrating structural analysis and geochronology with published geophysical data. The nature of this boundary is interpreted to be a consequence of an apparent stacking in the lower and middle crust initiating 1.87-1.86 Ga dextral shear along the Gävle-Rättvik Zone (GRZ) and adjacent shear zones, resulting in an arcuate northern boundary of the Bergslagen province. This boundary coincides with geophysical anomalies and temporal and metamorphic breaks. Owing to continuous convergence the pure-shear overprint component increased on the GRZ and caused a shift of dextral shear to the Hagsta Gneiss Zone with recorded shear at 1809 ± 2 Ma. Most likely, both these structures are related to coeval shear zones farther to the east as a part of an ˜1500 km long crustal, or possibly terrane, boundary.

  20. Dislocation-free zone model of fracture: The effect of transgranular microcrack nucleated from a grain-boundary ledge

    NASA Astrophysics Data System (ADS)

    Shiue, Sham-Tsong

    1994-08-01

    The effects of transgranular microcrack nucleated form a grain-boundary ledge on a dislocation-free zone model of fracture are investigated by a continuous dislocation modeling method. The dislocation distribution functions to simulate the crack and plastic zone, the number of dislocations in the crack and plastic zone, the stress field, and stress intensity factor at the crack tip are obtained. If the Burgers vector of dislocations composing the grain-boundary ledge has the same sign as that of the plastic zone dislocations, all the dislocation distributions that simulate the crack and plastic zone, the number of dislocations in the crack and plastic zone, the stress field in the dislocation-free zone, the tress intensity factor at the crack tip, the dislocation-free zone size, and the plastic zone size increase with an increasing number of grain-boundary ledge dislocation, but the applied stress sigma to accumulate the plastic zone dislocations decreases with an increasing number of grain-boundary ledge dislocations. The effects of transgranular microcrack nucleated from a grain-boundary ledge on a fracture without a dislocation-free zone are also considered. When there is no dislocation-free zone in front of the crack tip, the stress intensity factor is zero, regardless of whether the grain- boundary ledge dislocation exist.

  1. Heat Transfer at the Reattachment Zone of Separated Laminar Boundary Layers

    NASA Technical Reports Server (NTRS)

    Chung, Paul M.; Viegas, John R.

    1961-01-01

    The flow and heat transfer are analyzed at the reattachment zone of two-dimensional separated laminar boundary layers. The fluid is considered to be flowing normal to the wall at reattachment. An approximate expression is derived for the heat transfer in the reattachment region and a calculated value is compared with an experimental measurement.

  2. Sensitivities to source-term parameters of emergency planning zone boundaries for waste management facilities

    SciTech Connect

    Mueller, C.J.

    1995-07-01

    This paper reviews the key parameters comprising airborne radiological and chemical release source terms, discusses the ranges over which values of these parameters occur for plausible but severe waste management facility accidents, and relates the concomitant sensitivities of emergency planning zone boundaries predicted on calculated distances to early severe health effects.

  3. Sub-layers inside the entrainment zone of a dry, shear-free convective boundary layer

    NASA Astrophysics Data System (ADS)

    Garcia, Jade Rachele; Mellado, Juan Pedro

    2013-11-01

    The entrainment zone of a dry, shear-free convective boundary layer growing into a homogeneously stably-stratified fluid is studied using direct numerical simulation. Based on the self-similar analysis of the mean and variance buoyancy profiles, we identify two sub-layers within the entrainment zone, defined as the region of negative buoyancy flux: i) an upper sub-layer with a thickness comparable to the penetrative length scale based on the convective velocity and the buoyancy frequency of the free troposphere and ii) a lower sub-layer acting as a transition towards the mixed layer, with a thickness equal to a constant fraction of the boundary layer height. The capping region of the penetrative thermals belongs to the upper sub-layer of the entrainment zone, and the troughs between the penetrating thermals belong to the lower sub-layer of the entrainment zone. Correspondingly, different buoyancy scales are identified in the different regions; parametrizations thereof are provided and explained. This multiplicity of characteristic scales inside the entrainment zone helps to explain the uncertainty associated with previous analysis of entrainment zone properties and the difficulty to parametrize them based on a single length scale and a single buoyancy scale. Juelich Research Centre for the computing time.

  4. Kinematics to dynamics in the New Zealand plate-boundary zone

    NASA Astrophysics Data System (ADS)

    Lamb, S. H.

    2013-12-01

    New Zealand straddles the boundary between the Australian and Pacific plate, with a transition from subduction of Pacific oceanic lithosphere beneath North Island, to oblique continental collision in South Island. Cenozoic relative plate motion has resulted in a complex pattern of faulting and block rotation in a zone up to 250 km wide, with displacements on individual faults up to 100s of kilometres. Active deformation must be driven by a combination of plate-boundary forces and internal buoyancy forces. I use a compilation of seismic reflection/refraction studies and high quality receiver function analyses, together with simple Airy isostasy, to determine regional crustal and mantle structure. Integration of the vertical normal stress to the base of the deforming layer yields the buoyancy stress. Horizontal gradients of this can be compared with horizontal gradients of strain rate, using the method of England & Molnar (1997), in the context of a simple thin sheet model of deformation. Thus, if deformation is that of a Newtonian fluid, then appropriate combinations of the horizontal gradients of vorticity and dilatation are related to gradients of buoyancy stress by the fluid viscosity. However, the short term geodetic deformation is strongly biased by elastic strain accumulation related to locking on the plate interface, and cannot be used to determine the plate-boundary velocity field averaged over many seismic cycles (see Lamb & Smith 2013). Therefore, I derive here a velocity field for the plate-boundary zone, which is representative of deformation over tens of thousands of years. This is based on an inversion of fault slip, strain rate azimuth and paleomagnetic data, in the context of the short term relative plate motions, solved in a network of triangles spanning the plate-boundary, using the method of Lamb (2000). A comparison of gradients of buoyancy stress with the appropriate combinations of gradients of vorticity and dilatation shows that deformation in

  5. 77 FR 52680 - Foreign-Trade Zone 242-Boundary County, ID, Notification of Proposed Production Activity, AREVA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-30

    ... Foreign-Trade Zones Board Foreign-Trade Zone 242--Boundary County, ID, Notification of Proposed Production Activity, AREVA Enrichment Services, LLC, (Gas Centrifuge Production Equipment), Bonneville County, ID Boundary County, grantee of FTZ 242, submitted a notification of proposed production activity on behalf...

  6. Representation of the grey zone of turbulence in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Honnert, Rachel

    2016-04-01

    Numerical weather prediction model forecasts at horizontal grid lengths in the range of 100 to 1 km are now possible. This range of scales is the "grey zone of turbulence". Previous studies, based on large-eddy simulation (LES) analysis from the MésoNH model, showed that some assumptions of some turbulence schemes on boundary-layer structures are not valid. Indeed, boundary-layer thermals are now partly resolved, and the subgrid remaining part of the thermals is possibly largely or completely absent from the model columns. First, some modifications of the equations of the shallow convection scheme have been tested in the MésoNH model and in an idealized version of the operational AROME model at resolutions coarser than 500 m. Secondly, although the turbulence is mainly vertical at mesoscale (> 2 km resolution), it is isotropic in LES (< 100 m resolution). It has been proved by LES analysis that, in convective boundary layers, the horizontal production of turbulence cannot be neglected at resolutions finer than half of the boundary-layer height. Thus, in the grey zone, fully unidirectional turbulence scheme should become tridirectional around 500 m resolution. At Météo-France, the dynamical turbulence is modelled by a K-gradient in LES as well as at mesoscale in both MésoNH and AROME, which needs mixing lengths in the formulation. Vertical and horizontal mixing lengths have been calculated from LES of neutral and convective cases at resolutions in the grey zone.

  7. The memory of the accreting plate boundary and the continuity of fracture zones

    USGS Publications Warehouse

    Schouten, Hans; Klitgord, Kim D.

    1982-01-01

    A detailed aeromagnetic anomaly map of the Mesozoic seafloor-spreading lineations southwest of Bermuda reveals the dominant magnetic grain of the oceanic crust and the character of the accreting boundary at the time of crustal formation. The magnetic anomaly pattern is that of a series of elongate lobes perpendicular to the fracture zone (flowline) trends. The linear sets of magnetic anomaly peaks and troughs have narrow regions of reduced amplitude anomalies associated with the fracture zones. During the period of Mesozoic geomagnetic polarity reversals (when 1200 km of central North Atlantic seafloor formed), the Atlantic accreting boundary consisted of stationary, elongate, spreading center cells that maintained their independence even though sometimes only minor spatial offsets existed between cells. Normal oceanic crustal structure was formed in the spreading center cells, but structural anomalies and discontinuities characteristic of fracture zones were formed at their boundaries, which parallel flowlines of Mesozoic relative plate motion in the central North Atlantic. We suggest that the memory for a stationary pattern of independent spreading center cells resides in the young brittle lithosphere at the accreting boundary where the lithosphere is weakest; here, each spreading center cell independently goes through its cylce of stress buildup, stress release, and crustal accretion, after which its memory is refreshed. The temporal offset between the peaks of the accretionary activity that takes place within each cell may provide the mechanism for maintaining the independence of adjacent spreading center cells through times when no spatial offset between the cells exists.

  8. Boundaries of the Peruvian oxygen minimum zone shaped by coherent mesoscale dynamics

    NASA Astrophysics Data System (ADS)

    Bettencourt, João H.; López, Cristóbal; Hernández-García, Emilio; Montes, Ivonne; Sudre, Joël; Dewitte, Boris; Paulmier, Aurélien; Garçon, Véronique

    2015-12-01

    Dissolved oxygen in sea water affects marine habitats and biogeochemical cycles. Oceanic zones with oxygen deficits represent 7% of the volume and 8% of the area of the oceans, and are thought to be expanding. One of the most pronounced lies in the region off Peru, where mesoscale activity in the form of fronts and eddies is strong. Here, we study the dynamics of the Peruvian oxygen minimum zone in a Lagrangian framework, using a coupled physical-biogeochemical numerical model and finite-size Lyapunov exponent fields, to evaluate the role of mesoscale activity. We find that, at depths between 380 and 600 m, mesoscale structures have two distinct roles. First, their mean positions and paths delimit and maintain the oxygen minimum zone boundaries. Second, their high-frequency fluctuations inject oxygen across the oxygen minimum zone boundaries and eddy fluxes are one order of magnitude higher than mean oxygen fluxes. We conclude that these eddy fluxes contribute to the ventilation of the Peruvian oxygen minimum zone.

  9. Boundaries of intergrowths between mineral individuals: A zone of secondary mineral formation in aggregates

    NASA Astrophysics Data System (ADS)

    Brodskaya, R. L.; Bil'Skaya, I. V.; Lyakhnitskaya, V. D.; Markovsky, B. A.; Sidorov, E. G.

    2007-12-01

    Intergrowth boundaries between mineral individuals in dunite of the Gal’moenan massif in Koryakia was studied in terms of crystal morphology, crystal optics, and ontogenesis. The results obtained allowed us to trace the staged formation of olivine and chromite and four generations of these minerals. Micro-and nanotopography of boundary surfaces between intergrown mineral individuals of different generations was examined with optic, electron, and atomic force microscopes. The boundaries between mineral individuals of different generations are distinguished by their microsculpture for both olivine and chromite grains. Both minerals demonstrate a compositional trend toward refinement from older to younger generations. The decrease in the iron mole fraction in olivine and chromite is accompanied by the crystallization of magnetite along weakened zones in olivine of the first generation and as outer rims around the chromite grains of the second generation observable under optic and electronic microscopes. The subsequent refinement of chromite results in the release of PGE from its lattice, as established by atomic power microscopy. The newly formed PGM are localized at the boundaries between mineral individuals and, thus, mark a special stage in the ontogenetic evolution of mineral aggregates. Further recrystallization is expressed in the spatial redistribution of grain boundaries and the formation of monomineralic intergrowth boundaries, i.e., the glomerogranular structure of rock and substructures of PGM, chromite, and olivine grains as intermediate types of organization of the granular assemblies in the form of reticulate, chain, and cellular structures and substructures of aggregates.

  10. The MOLA Topographic signature at the crustal dichotomy boundary zone on Mars

    NASA Astrophysics Data System (ADS)

    Frey, Herbert; Sakimoto, Susan E.; Roark, James

    1998-12-01

    MOLA data collected during the aerobraking hiatus provide good longitudinal sampling of the crustal dichotomy boundary zone in eastern Mars and reveal a significant topographic signature associated with the transition from cratered highlands to lowland plains. Total relief between the two major units is always >2.5 km and sometimes >6 km; median elevation differences are about 4 km. Regional slopes are very low (<0.02°) in both cratered terrain south and in lowland plains north of the boundary. Within the transition zone where cratered terrain changes to detached plateaus, mesas and knobby terrain, slopes are 50-100 times steeper and over a few hundred kilometers average about 1°. The topographic signature of the boundary zone is best described as a 2-4 km step function between two nearly flat surfaces, similar in slope and amplitude to some terrestrial passive margins. This supports previous conclusions of a significant difference in crustal properties (thickness, composition, or both) between the lowland plains and cratered terrain, and suggests this difference occurs over a relatively short distance of a few to several hundred kilometers.

  11. Extension and transtension in the plate boundary zone of the northeastern Caribbean

    SciTech Connect

    Speed, R.C. ); Larue, D.K. )

    1991-03-01

    The authors propose that the Caribbean (Ca)-North American (NA) plate boundary zone (pbz) from the Puerto Rico Trench to the Venezuelan Basin from Mona Canyon east has been in left-transtension over the last 15-20 ma. A boundary-normal component of extension occurs throughout the pbz and is a principal cause of the Puerto Rico Trench. Such extension is due to WNW velocity of NA-Ca and the northward pullaway of NA from its S-dipping slab, which is below Puerto Rico. Strike slip motion may be taken up among terranes in the pbz by rigid CCW rotation and by oblique slip at their boundaries. Rotation of the largest terrane, Puerto Rico-Virgin Islands (PRVI), has caused such major structures as the Muertos thrust and Anegada Passage. The model implies NA-Ca velocity estimated from Cayman transforms is more accurate than that from slip vectors from seisms in the NA slab.

  12. Kinematics to dynamics in the New Zealand plate-boundary zone

    NASA Astrophysics Data System (ADS)

    Lamb, Simon

    2014-05-01

    New Zealand straddles the boundary between the Australian and Pacific plate, with a transition from subduction of Pacific plate oceanic lithosphere in the North, beneath North Island to oblique continental collision in South Island. Cenozoic relative plate motion has resulted in a complex pattern of faulting and block rotation in a zone up to 250 km wide, with displacements on individual faults up to 100s of kilometres. Here, I use a compilation of seismic reflection/refraction studies and high quality receiver function analyses, together with simple Airy isostasy, to determine the regional crustal and mantle structure. The buoyancy stress in the deforming layer is calculated by integrating the vertical normal stress with depth. This, in combination with plate-boundary stresses, must drive deformation. Horizontal gradients of buoyancy stress can be compared with horizontal gradients of strain rate, using the method of England & Molnar (1997), in the context of a simple thin sheet model of lithospheric deformation. I derive a velocity field for the New Zealand plate-boundary zone, using the method of Lamb (2000). This is representative of deformation over tens of thousands of years, based on fault slip, strain rate azimuth and paleomagnetic data, in the context of the short term relative plate motions. Comparison of appropriate combinations of horizontal gradients of vorticity and dilatation with horizontal gradients of buoyancy stress shows that deformation has some of the features of a Newtonian fluid. In detail, the minima in buoyancy stress, calculated from the vertical density structure, are offset horizontally from that calculated from gradients of strain rate, suggesting strong lateral contrasts in viscosity if deformation is strongly coupled at all levels in the lithosphere, with viscosities in the range 1 - 10 x 10**21 Pa s. However, subduction of Pacific plate lithosphere along the Hikurangi margin, and evidence for underthrusting beneath the Southern Alps

  13. Lost in Iceland? Fracture Zone Complications Along the Mid-Atlantic Plate Boundary

    NASA Astrophysics Data System (ADS)

    Brandsdóttir, B.; Einarsson, P.; Detrick, R. S.; Mayer, L.; Calder, B.; Driscoll, N.; Richter, B.

    2003-12-01

    The mid-Atlantic plate boundary breaks up into a series of segments across Iceland. Two transform zones, the South Iceland Seismic Zone (SISZ) and the Tjörnes Fracture Zone (TFZ) separate the on land rift zones from the Reykjanes Ridge (RR), and the Kolbeinsey Ridge (KR), offshore N-Iceland. Both are markedly different from fracture zones elsewhere along the plate boundary. The 80 km E-W and 10--15 km N-S SISZ is made up of more than 20 N-S aligned, right-lateral, strike-slip faults whereas the TFZ consists of a broad zone of deformation, roughly 150 km E-W and 75 km N-S. The over-all left-lateral transform motion within the SISZ is accommodated by bookshelf faulting whereas the right-lateral transform motion within the TFZ is incorporated within two WNW-trending seismic zones, spaced ˜40 km apart, the Grímsey Seismic Zone (GSZ) and the Húsavík-Flatey fault (HFF). Recently collected EM300 and RESON8101 multibeam bathymetric data along with CHIRP subbottom data has unveiled some tectonic details within the TFZ. The GSZ runs along the offshore extension of the Northern Volcanic Rift Zone (NVRZ) and is made up of four left-stepping, en-echelon, NS-striking rift segments akin to those on land. Large GSZ earthquakes seem to be associated with lateral strike-slip faulting along ESE-striking fault planes. Fissure swarms transecting the offshore volcanic systems have also been subjected to right-lateral transformation along the spreading direction. As the Reykjanes Peninsula, the on land extension of the RR, the GSZ bears the characteristics of an oblique rift zone. The plate boundary segments connecting to the RR and KR are thus symmetrical with respect to the plate separation vector (105° ) and orientation of individual volcanic systems. The HFF has an overall strike of N65° W and can be traced continuously along its 75--80 km length, between the Theistareykir volcanic system within the NVRZ, across the central TFZ-graben, the Skjálfandi bay, and into the largest

  14. Identification of a major segment boundary between two megathrust subduction zone earthquakes from aftershock seismicity

    NASA Astrophysics Data System (ADS)

    Sobiesiak, M.; Victor, P.; Eggert, S.

    2009-04-01

    Aftershock seismicity is commonly used to characterize the extent of rupture planes of megathrust earthquakes. From unique datasets, covering the two adjacent fault planes of the Mw 8.0, 1995, Antofagasta and the Mw 7.7, 2007, Tocopilla earthquakes, we were able to identify a segment boundary (SB), located beneath Mejillones Peninsula. This segment boundary hosted the onset of the Antofagasta rupture and constituted the end of the Tocopilla rupture plane. The data recorded during the mission of the German Task Force for Earthquakes after the 2007 Tocopilla earthquake is supporting our observations regarding the northern part of the SB. 34 seismological stations registered the aftershocks from November 2007 until May 2008. First hypocenter determinations show that the aftershock sequences of both events meet along this E-W oriented segment boundary. The segment boundary is furthermore conformed by the historic record of megathrust events. Evidence for long term persistency of this SB comes from geological observations as differential uplift rates across the boundary and different fault patterns. Geomorpholocical analysis defines a topographic anomaly ~ 20 km wide and oriented along strike the SB..The main shock hypocenter determinations (NEIC, local network, ISC) which are related to the start of the rupture are all located in this zone. The SB is further characterized by intermediate b-values derived from a spatial b-value study of the Antofagasta fault plane and hosts several elongated clusters of aftershock seismicity. A detailed study of the focal mechanism solutions in one of these clusters showed a number of aligned strike slip events with one E-W striking nodal plane having a strike angle which is similar to the angle of subduction obliquity of the oceanic Nazca plate in this area. In further investigations we will search for detailed information on the nature and dynamics of processes along such a segment boundary, their meaning for the initiation of large

  15. Rheological structure of the lithosphere in plate boundary strike-slip fault zones

    NASA Astrophysics Data System (ADS)

    Chatzaras, Vasileios; Tikoff, Basil; Kruckenberg, Seth C.; Newman, Julie; Titus, Sarah J.; Withers, Anthony C.; Drury, Martyn R.

    2016-04-01

    How well constrained is the rheological structure of the lithosphere in plate boundary strike-slip fault systems? Further, how do lithospheric layers, with rheologically distinct behaviors, interact within the strike-slip fault zones? To address these questions, we present rheological observations from the mantle sections of two lithospheric-scale, strike-slip fault zones. Xenoliths from ˜40 km depth (970-1100 ° C) beneath the San Andreas fault system (SAF) provide critical constraints on the mechanical stratification of the lithosphere in this continental transform fault. Samples from the Bogota Peninsula shear zone (BPSZ, New Caledonia), which is an exhumed oceanic transform fault, provide insights on lateral variations in mantle strength and viscosity across the fault zone at a depth corresponding to deformation temperatures of ˜900 ° C. Olivine recrystallized grain size piezometry suggests that the shear stress in the SAF upper mantle is 5-9 MPa and in the BPSZ is 4-10 MPa. Thus, the mantle strength in both fault zones is comparable to the crustal strength (˜10 MPa) of seismogenic strike-slip faults in the SAF system. Across the BPSZ, shear stress increases from 4 MPa in the surrounding rocks to 10 MPa in the mylonites, which comprise the core of the shear zone. Further, the BPSZ is characterized by at least one order of magnitude difference in the viscosity between the mylonites (1018 Paṡs) and the surrounding rocks (1019 Paṡs). Mantle viscosity in both the BPSZ mylonites and the SAF (7.0ṡ1018-3.1ṡ1020 Paṡs) is relatively low. To explain our observations from these two strike-slip fault zones, we propose the "lithospheric feedback" model in which the upper crust and lithospheric mantle act together as an integrated system. Mantle flow controls displacement and the upper crust controls the stress magnitude in the system. Our stress data combined with data that are now available for the middle and lower crustal sections of other transcurrent fault

  16. Modeling the Philippine Mobile Belt: Tectonic blocks in a deforming plate boundary zone

    NASA Astrophysics Data System (ADS)

    Galgana, G. A.; Hamburger, M. W.; McCaffrey, R.; Bacolcol, T. C.; Aurelio, M. A.

    2007-12-01

    The Philippine Mobile Belt, a seismically active, rapidly deforming plate boundary zone situated along the convergent Philippine Sea/Eurasian plate boundary, is examined using geodetic and seismological data. Oblique convergence between the Philippine Sea Plate and the Eurasian plate is accommodated by nearly orthogonal subduction along the Philippine Trench and the Manila Trench, as well as by strike-slip faulting along the Philippine Fault system. We develop a model of active plate boundary deformation in this region, using elastic block models constrained by known fault geometries, published GPS observations and focal mechanism solutions. We then present an estimate of block rotations, fault coupling, and intra-block deformation, based on the best-fit model that minimizes the misfit between observed and predicted geodetic vectors and earthquake slip vectors. Slip rates along the Philippine fault vary from ~22 - 36 mm/yr in the Central Visayas and about 10 to 40 mm/yr in Luzon, trending almost parallel to the fault trace. In northern Luzon, Philippine Fault splays accommodate transpressional strain. The Central Visayas block experiences convergence with the Sundaland block along the Negros Trench and the Mindoro-Palawan collision zone. On the eastern side of Central Visayas, sinistral strike-slip faulting occurs along the NNW-SSE-trending Philippine Fault. Mindanao Island in southern Philippines is dominated by east-verging subduction along the Cotabato Trench, and strain partitioning (strike- slip faulting with west-verging subduction) in eastern Mindanao along the southern Philippine Fault and Philippine Trench, respectively. Oblique active sinistral strike slip faults in Central and Eastern Mindanao that were hypothesized to be responsible for basin formation are obvious boundaries for tectonic blocks. Located south of Mindanao Island we define an adjoining oceanic block defined by the N-S trending complex dual subduction zone of Sangihe and Halmahera

  17. 77 FR 55800 - Foreign-Trade Zone 242-Boundary County, ID; Application for Subzone AREVA Enrichment Services...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Foreign-Trade Zone 242--Boundary County, ID; Application for Subzone AREVA Enrichment Services, LLC; Bonneville County, ID An application has been submitted to the Foreign-Trade...

  18. First epoch geodetic measurements with the Global Positioning System across the northern Caribbean plate boundary zone

    NASA Technical Reports Server (NTRS)

    Dixon, T. H.; Gonzalez, G.; Lichten, S. M.; Katsigris, E.

    1991-01-01

    The first geodetic survey across the northern Caribbean plate boundary zone with GPS was conducted in June 1986. Baseline vectors defined by the six-station regional GPS network ranged from 170 to 1260 km in length. Repeatability of independent daily baseline estimates was better than 8 mm plus 1.3 parts in 10 to the 8th of baseline length for horizontal components. The wet tropospheric path delay during the experiment was both high, sometimes exceeding 30 cm at zenith, and variable, sometimes exceeding 5 cm variation over several hours. Successful carrier phase cycle ambiguity resolution (bias fixing) could not be achieved prior to construction of a regional troposphere model. With optimum troposphere treatment and single-day orbital arcs, most biases on baselines were resolved up to about 550 km in length. With multiday orbital arcs most biases in the network were resolved regardless of baseline length. The results suggest that constraints on plate-boundary zone deformation in the Greater Antilles, and on the North America-Caribbean relative plate motion vector, can be obtained with a series of GPS experiments spanning less than 10 and 15 years, respectively.

  19. Plate Tectonics: From Plate Boundary Zone Tectonics To Extensive Intraplate Tectonics

    NASA Astrophysics Data System (ADS)

    Ishikawa, M.

    2004-12-01

    Plates makes up earth's surface, and tectonic activity is generally concentrated on plate boundary zones. In restrict meaning, plate tectonics of the earth is regarded as mixture of plate boundary zone tectonics and extensive intraplate tectonics. For example, the Asian continent never behaves as rigid plate that was deformed extensively when the Indian continent collided with it. I infer that extensive intraplate tectonics reflects rheological weakening of wet mantle. To demonstrate effect of H2O component on plate strength, one-dimensional rheological profiles of 100 km depth were constructed by assuming 20km thick upper crust and 20km thick lower crust. Temperature-depth profiles were calculated based on one-dimensional steady-state static heat transfer at given surface heat flows. Power law creep and Byerlee_fs law were used to estimate strength in ductile regime and brittle regime respectively. Creep strength for upper crust, lower crust, dry mantle and wet mantle were calculated using creep parameters of granite, granulite, dry dunite and wet dunite. The minimum value between power law creep strength and Byerlee_fs law strength gives the strength of the lithosphere. Strength profile at surface heat flow of 55mW/m2 (continental average is 56.5mW/m2) and strain rate of 10-15/s (intraplate deformation is about 10-15/s - 10-16/s in Asia) shows a significant difference in strength for using dry mantle and wet mantle. In case of dry mantle, the uppermost mantle is quite strong. However, if wet peridotite represent the upper mantle, there is very little strength in the uppermost mantle. The cumulative lithospheric strength, i.e. integral strength from surface to 100km depth, and the cumulative mantle strength, i.e. integral strength from 40km to 100km depth were calculated with changing strain rate. For example, to deform continental lithosphere at strain rate of 10-15/s, wet mantle has a cumulative strength of about 2x1012N/m whereas the cumulative strength of dry

  20. Tectonic lineaments in the cenozoic volcanics of southern Guatemala: Evidence for a broad continental plate boundary zone

    NASA Technical Reports Server (NTRS)

    Baltuck, M.; Dixon, T. H.

    1984-01-01

    The northern Caribbean plate boundary has been undergoing left lateral strike slip motion since middle Tertiary time. The western part of the boundary occurs in a complex tectonic zone in the continental crust of Guatemala and southernmost Mexico, along the Chixoy-Polochic, Motogua and possibly Jocotan-Chamelecon faults. Prominent lineaments visible in radar imagery in the Neogene volcanic belt of southern Guatemala and western El Salvador were mapped and interpreted to suggest southwest extensions of this already broad plate boundary zone. Because these extensions can be traced beneath Quaternary volcanic cover, it is thought that this newly mapped fault zone is active and is accommodating some of the strain related to motion between the North American and Caribbean plates. Onshore exposures of the Motoqua-Polochic fault systems are characterized by abundant, tectonically emplaced ultramafic rocks. A similar mode of emplacement for these off shore ultramafics, is suggested.

  1. Theory of a zone-boundary collective state in A1: A model calculation

    NASA Astrophysics Data System (ADS)

    Sturm, K.; Oliveira, L. E.

    1984-10-01

    A two-band model, which previously was used successfully to evaluate the optical absorption in A1, is applied to derive the k-->- and ω-dependent dielectric function ɛM(k-->,ω) for k--> parallel to the [100] direction with use of degenerate perturbation theory. Within the nearly-free-electron approximation, it is shown that a pair of (200) Bragg planes gives rise to another pole in the energy-loss function Im[-1ɛ] and hence to a collective mode. Both the dispersion of the mode throughout the first Brillouin zone and the strength of the mode are evaluated and are found to agree very well with electron-energy-loss spectroscopy data. A detailed discussion of the nature of this mode is given. The mode is of the same origin as the so-called zone-boundary collective state (ZBCS) first proposed by Foo and Hopfield in Na. Comparison is made with a numerical calculation of ɛM(k-->,ω) by Singhal for some discrete k--> values. The general importance of the ZBCS for the understanding of the energy-loss spectrum and for more complicated systems is pointed out.

  2. Life on the boundary: Environmental factors as drivers of habitat distribution in the littoral zone

    NASA Astrophysics Data System (ADS)

    Cefalì, Maria Elena; Cebrian, Emma; Chappuis, Eglantine; Pinedo, Susana; Terradas, Marc; Mariani, Simone; Ballesteros, Enric

    2016-04-01

    The boundary between land and sea, i.e. the littoral zone, is home to a large number of habitats whose distribution is primarily driven by the distance to the sea level but also by other environmental factors such as littoral's geomorphological features, wave exposure, water temperature or orientation. Here we explore the relative importance of those major environmental factors that drive the presence of littoral rocky habitats along 1100 Km of Catalonia's shoreline (Spain, NW Mediterranean) by using Geographic Information Systems and Generalized Linear Models. The distribution of mediolittoral and upper infralittoral habitats responded to different environmental factors. Mediolittoral habitats showed regional differences drawn by sea-water temperature and substrate type. Wave exposure (hydrodynamism), slope and geological features were only relevant to those mediolittoral habitats with specific environmental needs. We did not find any regional pattern of distribution in upper infralittoral habitats, and selected factors only played a moderate role in habitat distribution at the local scale. This study shows for the first time that environmental factors determining habitat distribution differ within the mediolittoral and the upper infralittoral zones and provides the basis for further development of models oriented at predicting the distribution of littoral marine habitats.

  3. Longriba fault zone in eastern Tibet: An important tectonic boundary marking the westernmost edge of the Yangtze block

    NASA Astrophysics Data System (ADS)

    Guo, Xiaoyu; Gao, Rui; Xu, Xiao; Keller, G. Randy; Yin, An; Xiong, Xiaosong

    2015-05-01

    Global Positioning System (GPS) measurements across eastern Tibet reveal a sharp velocity gradient zone located about 150 km west of the Longmen Shan frontal thrust zone, where eastward block motion of Tibet decreases from ~12 mm/yr to ~3 mm/yr over a distance of less than 10 km. In order to investigate the tectonic cause for this rapid change in GPS velocity, together with systematic review on the available geological and geophysical data in easternmost Tibet, we provide new constraints on the tectonic feature of the Longriba fault zone from Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar data. We propose that the NE striking Longriba fault zone is the key structure responsible for the observed sharp gradient in GPS velocities. In addition, the evidence indicates that the Longriba fault zone, instead of the Longmen Shan fault zone, marks the westernmost edge of the Yangtze crustal block. Given the irregular western margin of the Yangtze block, the Longriba fault zone represents part of the actual tectonic boundary between the Songpan-Ganzi terrane and the Yangtze block. The newly identified western edge of the Yangtze block implies a paleocontinent-ocean boundary at depth. This boundary was a potential weak zone and may have been exploited during the formation of the Longriba fault zone. The results of this paper should advance our understanding of the tectonic relationship between the Songpan-Ganzi terrane and Yangtze block and provide additional constraints for studies of the geodynamic response of eastern Tibet to the ongoing India-Eurasia collision.

  4. Thinking and meddling with boundaries: Critical reflections on Matthew Weinstein's narrative of street medics, red-zones and glop

    NASA Astrophysics Data System (ADS)

    Alsop, Steve

    2015-03-01

    In pursuit of more mindful notions of hybridity, this review essay provides a series of reflections on Mathew Weinstein's representations of Street Medics and `sciences for the red zones of neoliberalism'. My analysis draws on three popular ways of thinking with boundaries to offer a critical reading of the boundary-work that the essay performs with respect to three dialectics: (1) technical and political; (2) disciplinarily and multidisciplinarities; and (3) structures and agencies. I conclude with reflections on my boundary labour as a researcher, writer and pedagogue and how such cultural work might learn to live better with difference, ambiguities, hybrids and cross-hybrid learning.

  5. Consolidation patterns during initiation and evolution of a plate-boundary decollement zone: northern Barbados accretionary prism

    USGS Publications Warehouse

    Moore, J.C.; Klaus, A.; Bangs, N.L.; Bekins, B.; Bucker, C.J.; Bruckmann, W.; Erickson, S.N.; Hansen, O.; Horton, T.; Ireland, P.; Major, C.O.; Moore, G.F.; Peacock, S.; Saito, S.; Screaton, E.J.; Shimeld, J.W.; Stauffer, P.H.; Taymaz, T.; Teas, P.A.; Tokunaga, T.

    1998-01-01

    Borehole logs from the northern Barbados accretionary prism show that the plate-boundary decollement initiates in a low-density radiolarian claystone. With continued thrusting, the decollement zone consolidates, but in a patchy manner. The logs calibrate a three-dimensional seismic reflection image of the decollement zone and indicate which portions are of low density and enriched in fluid, and which portions have consolidated. The seismic image demonstrates that an underconsolidated patch of the decollement zone connects to a fluid-rich conduit extending down the decollement surface. Fluid migration up this conduit probably supports the open pore structure in the underconsolidated patch.

  6. Recharge and Lateral Groundwater Flow Boundary Conditions for the Saturated Zone Site-Scale Flow and Transport Model

    SciTech Connect

    B. Arnold; T. Corbet

    2001-12-18

    The purpose of the flow boundary conditions analysis is to provide specified-flux boundary conditions for the saturated zone (SZ) site-scale flow and transport model. This analysis is designed to use existing modeling and analysis results as the basis for estimated groundwater flow rates into the SZ site-scale model domain, both as recharge at the upper (water table) boundary and as underflow at the lateral boundaries. The objective is to provide consistency at the boundaries between the SZ site-scale flow model and other groundwater flow models. The scope of this analysis includes extraction of the volumetric groundwater flow rates simulated by the SZ regional-scale flow model to occur at the lateral boundaries of the SZ site-scale flow model and the internal qualification of the regional-scale model for use in this analysis model report (AMR). In addition, the scope includes compilation of information on the recharge boundary condition taken from three sources: (1) distributed recharge as taken from the SZ regional-scale flow model, (2) recharge below the area of the unsaturated zone (UZ) site-scale flow model, and (3) focused recharge along the Fortymile Wash channel.

  7. The Ailao Shan-Red River shear zone (Yunnan, China), Tertiary transform boundary of Indochina

    NASA Astrophysics Data System (ADS)

    Leloup, Philippe Hervé; Lacassin, Robin; Tapponnier, Paul; Schärer, Urs; Zhong, Dalai; Liu, Xiaohan; Zhang, Liangshang; Ji, Shaocheng; Trinh, Phan Trong

    1995-12-01

    The Red River Fault zone (RRF) is the major geological discontinuity that separates South China from Indochina. Today it corresponds to a great right-lateral fault, following for over 900 km the edges of four narrow (< 20 km wide) high-grade gneiss ranges that together form the Ailao Shan-Red River (ASRR) metamorphic belt: the Day Nui Con Voi in Vietnam, and the Ailao, Diancang and Xuelong Shan in Yunnan. The Ailao Shan, the longest of those ranges, is fringed to the south by a strip of low-grade schists that contain ultramafic bodies. The ASRR belt has thus commonly been viewed as a suture. A detailed study of the Ailao and Diancang Shan shows that the gneiss cores of the ranges are composed of strongly foliated and lineated mylonitic gneisses. The foliation is usually steep and the lineation nearly horizontal, both being almost parallel to the local trend of the gneissic cores. Numerous shear criteria, including asymmetric tails on porphyroclasts, C-S or C'-S structures, rolling structures, asymmetric foliation boudinage and asymmetric quartz axis fabrics, indicate that the gneisses have undergone intense, progressive left-lateral shear. P-T studies show that left-lateral strain occurred under amphibolite-facies conditions (3-7 kb and 550-780°C). In both ranges high-temperature shear was coeval with emplacement of leucocratic melts. Such deformed melts yield {U}/{Pb} ages between 22.4 and 26.3 Ma in the Ailao Shan and between 22.4 and 24.2 Ma in the Diancang Shan, implying shear in the Lower Miocene. The mylonites in either range rapidly cooled to ≈ 300°C between 22 and 17 Ma, before the end of left-lateral motion. The similarity of deformation kinematics, P-T conditions, and crystallization ages in the aligned Ailao and Diancang Shan metamorphic cores, indicate that they represent two segments of the same Tertiary shear zone, the Ailao Shan-Red River (ASRR) shear zone. Our results thus confirm the idea that the ASRR belt was the site of major left

  8. HRM investigation of the structure of the sigma 5(310)/zone axes (001) symmetric tilt grain boundary in Nb

    NASA Astrophysics Data System (ADS)

    King, W. E.; Coombs, A.; Campbell, G. H.; Mills, M. J.

    1990-11-01

    Recent atomistic simulations using interatomic potentials for Nb developed employing the embedded atom method (EAM) and the model generalized pseudopotential theory (MGPT) have indicated a possible cusp at the Sigma 5(310) orientation in the energy vs. tilt angle curves for zone axes group 001 symmetric tilt grain boundaries. In addition, the most stable structure predicted using EAM exhibits shifts of one crystal relative to the other along the tilt axis and along the direction perpendicular to the tilt axis lying in the boundary plane. The structure predicted using the MGPT was mirror symmetric across the plane of the grain boundary. This boundary was n prepared for experimental study using the ultra high vacuum diffusion bonding methods. A segment of this boundary was studied using high resolution electron microscopy.

  9. Subcrustal earthquakes in the plate boundary zone of New Zealand's South Island

    NASA Astrophysics Data System (ADS)

    Boese, C. M.; Stern, T. A.; Townend, J.; Sheehan, A. F.; Molnar, P. H.; Collins, J. A.; Karalliyadda, S.; Bourguignon, S.; Bannister, S. C.

    2012-12-01

    Sporadic, intermediate-depth earthquakes have been observed for ~40 years in the vicinity of the Alpine Fault, a 460 km-long transpressive fault forming the western boundary of the Southern Alps. The Alpine Fault represents the plate boundary between the Australian and Pacific Plates in New Zealand and links two subduction zones of opposite polarity in the North and South. Several earthquakes at depths of 59-85 km have been recorded by the Southern Alps Microearthquake Borehole Array (SAMBA) since its deployment in November 2008. Due to large numbers of impulsive phase arrivals, focal mechanisms were obtained for these events during routine processing. In 2009 and early 2010, several additional temporary seismometer networks were operating in the central Southern Alps (Alpine Fault Array ALFA, Deep Fault Drilling Project 2010 DFDP10) and the offshore region west of the South Island (Marine Observations of Anisotropy Near Aotearoa MOANA). To gain more insight about the cause and mechanism of these deep events, a comprehensive analysis has been performed incorporating data from all available instruments. Accurate hypocentres of 22 earthquakes (ML<4) and focal mechanisms of at least 14 events have been obtained. The focal mechanisms reveal that reverse faulting predominates at depth in the continental collision zone between the Pacific and Australian Plates. The intermediate-depth events occur below the Moho discontinuity, which has been mapped in detail using wide-angle reflection/refraction data obtained during the South Island Geophysical Transect (SIGHT) project in 1995/96. Although the cause for these subcrustal earthquakes is not yet clear, they have previously been interpreted to result from intra-continental subduction (Reyners 1987), high shear-strain gradients due to depressed geotherms and viscous deformation of mantle lithosphere (Kohler and Eberhart-Phillips 2003). On the basis of the locations and mechanisms obtained using SAMBA, we have argued that

  10. Young tectonics of a complex plate boundary zone: Indentation, rotation, and escape in Alaska

    NASA Astrophysics Data System (ADS)

    Wallace, W. K.; Ruppert, N. A.

    2012-12-01

    Convergence of thick crust of the Yakutat block with the southern margin of Alaska is widely recognized as a dominant influence on the tectonics of Alaska since at least late Miocene time. It is less clear how this convergence relates to the distribution, type, and orientation of geologic structures, and to the boundaries between the tectonic provinces that they define. We propose that convergence of Yakutat block includes two distinct components that influence deformation and topography in different ways: 1) The crust of the exposed, southern Yakutat block is too thick to subduct, which has caused the collisional St. Elias orogen. Detachment of the upper part of the mafic basement allows delamination and sinking of the remaining mafic crust and lithospheric mantle. The collisional orogen drives rigid counterclockwise rotation of the southern Alaska block south of the arcuate, right-lateral Denali fault. The western boundary of this block is a zone of distributed contraction in the western Alaska Range and Cook Inlet. 2) The northern part of the Yakutat block is thin enough to subduct but thick and buoyant enough to cause localized flat-slab subduction orthogonal to rotation of the southern Alaska block. Consequences include the gently antiformal Talkeetna Mountains that span the forearc basin, a gap in the magmatic arc, and a basement-involved fold-and-thrust belt in the northern Alaska Range. An arcuate oroclinal hinge from southern Alaska to the northeastern Brooks Range reflects indentation since at least Paleocene time. Traction above the subducted Yakutat block along the southern part of this hinge drives current indentation. North of the subducted Yakutat block, indentation is reflected by left-lateral block rotation that accommodates shortening between the Denali and Tintina faults and by contraction farther north along the northern edge of the arcuate northeastern Brooks Range. Western Alaska accommodates both northward indentation and westward convergence

  11. Analysis of subgrid-scale vertical transport in convective boundary layers at gray-zone resolutions

    NASA Astrophysics Data System (ADS)

    Shin, Hyeyum Hailey; Hong, Song-You

    2013-04-01

    The gray zone of a physics process in numerical models is defined as the range of model resolution in which the process is partly resolved by model dynamics and partly parameterized. In this study, we examine the effects of grid size on resolved and parameterized vertical transport for horizontal grid scales including the gray zone. To assess how stability alters the dependency on grid size, four convective boundary layer (CBL)s with different surface heating and geostrophic winds are considered. For this purpose, reference data for grid-scale (GS) and subgrid-scale (SGS) fields are constructed for 50-4000 mesh sizes by filtering 25-m large-eddy simulations (LES) data. As wind shear becomes stronger, turbulent kinetic energy and the vertical transport of potential temperature and momentum are more resolved for a given grid spacing. A passive scalar with bottom-up diffusion behaves in a similar fashion. For a top-down diffusion scalar, the cospectral peak scale of the scalar flux is larger than the horizontal size of the thermals and increases in time. For the scalar, the entrainment ratio, in conjunction with the shear, influences the mesh-size dependency of GS and SGS transport. The total vertical transport of heat and the bottom-up scalar is decomposed into a non-local mixing owing to the coherent structures and remaining local mixing. The contribution of the resolved parts is larger when roll-like structures are present than when only thermals exist, for both non-local and local fluxes. The grid-size dependency of the non-local flux and its sensitivity to stability predominantly determines the dependency of total (non-local plus local) transport.

  12. Sharp acoustic boundaries across an altitudinal avian hybrid zone despite asymmetric introgression.

    PubMed

    Halfwerk, W; Dingle, C; Brinkhuizen, D M; Poelstra, J W; Komdeur, J; Slabbekoorn, H

    2016-07-01

    Birdsong is a sexually selected trait that could play an important evolutionary role when related taxa come into secondary contact. Many songbird species, however, learn their songs through copying one or more tutors, which complicates the evolutionary outcome of such contact. Two subspecies of a presumed vocal learner, the grey-breasted wood-wren (Henicorhina leucophrys), replace each other altitudinally across the western slope of the Ecuadorian Andes. These subspecies are morphologically very similar, but show striking differences in their song. We examined variation in acoustic traits and genetic composition across the altitudinal range covered by both subspecies and between two allopatric populations. The acoustic boundary between the subspecies was found to be highly abrupt across a narrow elevational range with virtually no evidence of song convergence. Mixed singing and use of hetero-subspecific song occurred in the contact zone and was biased towards the use of leucophrys song types. Hetero-subspecific song copying by hilaris and not by leucophrys reflected a previously found asymmetric pattern of response to song playback. Using amplified fragment length polymorphisms (AFLP) markers, we detected hybridization in the contact zone and asymmetric introgression in parapatric populations, with more leucophrys alleles present in hilaris populations than vice versa. This pattern may be a trail of introgression due to upslope displacement of leucophrys by hilaris. Our data suggest that song learning may impact speciation and hybridization in contrasting ways at different spatial scales: although learning may speed up population divergence in songs, thereby enhancing assortative mating and reducing gene flow, it may at a local level also lead to the copying of heterospecific songs, therefore allowing some level of hybridization and introgression. PMID:27037611

  13. The physical modeling of grain boundary liquation mechanisms within the heat-affected zone of an aluminum-copper alloy

    NASA Astrophysics Data System (ADS)

    Wilson, Andre Lamont

    This dissertation describes the results of a research program which was conducted to physically model, weld heat-affected zone (HAZ) liquation processes observed in Aluminum alloys during welding in the absence of an external strain. Three liquation processes were analyzed using a binary Al-3Cu alloy: (1) intergranular liquid infiltration from the fusion zone; (2) sub-solidus (below the equilibrium solidus temperature) grain boundary liquation due to non-equilibrium segregation during welding; and, (3) sub-solidus liquation (constitutional liquation) of undissolved precipitates in the matrix and along the grain boundary. Silicon, from an Al-Si filler metal, was observed at the base metal, HAZ grain boundaries, of a solution treated Al-3Cu alloy after gas-tungsten arc welding. With no evidence for crack-backfilling, the mechanism of transport of fusion zone material into the matrix was tentatively identified as liquid metal penetration of grain boundaries governed by liquid diffusion kinetics. Grain boundary regions in the heat-affected zone (HAZ) of arc welds, in a solution treated Al-3Cu alloy, were examined for liquation susceptibility. The welding experiments showed that certain grain boundaries, adjacent to the fusion line, were depleted in solute (copper), but were not liquated. Investigation of the third mechanism, involved a comprehensive study of the solid-state, dissolution and liquation-dissolution of matrix and grain boundary precipitates. This represents the first complete study of its type, for any alloy system. The isothermal kinetics of solid-state and liquation-dissolution of theta (Al2Cu) precipitates, were fully quantified during salt bath annealing. The stability of the grain boundary precipitate dispersion was examined in order to determine the susceptibility of the grain boundary microstructure to liquation. These latter experiments were facilitated by a large, "static" grain structure, and this study may mark the first time that any grain

  14. Propagation of acoustic shock waves between parallel rigid boundaries and into shadow zones

    NASA Astrophysics Data System (ADS)

    Desjouy, C.; Ollivier, S.; Marsden, O.; Dragna, D.; Blanc-Benon, P.

    2015-10-01

    The study of acoustic shock propagation in complex environments is of great interest for urban acoustics, but also for source localization, an underlying problematic in military applications. To give a better understanding of the phenomenon taking place during the propagation of acoustic shocks, laboratory-scale experiments and numerical simulations were performed to study the propagation of weak shock waves between parallel rigid boundaries, and into shadow zones created by corners. In particular, this work focuses on the study of the local interactions taking place between incident, reflected, and diffracted waves according to the geometry in both regular or irregular - also called Von Neumann - regimes of reflection. In this latter case, an irregular reflection can lead to the formation of a Mach stem that can modify the spatial distribution of the acoustic pressure. Short duration acoustic shock waves were produced by a 20 kilovolts electric spark source and a schlieren optical method was used to visualize the incident shockfront and the reflection/diffraction patterns. Experimental results are compared to numerical simulations based on the high-order finite difference solution of the two dimensional Navier-Stokes equations.

  15. Propagation of acoustic shock waves between parallel rigid boundaries and into shadow zones

    SciTech Connect

    Desjouy, C. Ollivier, S.; Dragna, D.; Blanc-Benon, P.; Marsden, O.

    2015-10-28

    The study of acoustic shock propagation in complex environments is of great interest for urban acoustics, but also for source localization, an underlying problematic in military applications. To give a better understanding of the phenomenon taking place during the propagation of acoustic shocks, laboratory-scale experiments and numerical simulations were performed to study the propagation of weak shock waves between parallel rigid boundaries, and into shadow zones created by corners. In particular, this work focuses on the study of the local interactions taking place between incident, reflected, and diffracted waves according to the geometry in both regular or irregular – also called Von Neumann – regimes of reflection. In this latter case, an irregular reflection can lead to the formation of a Mach stem that can modify the spatial distribution of the acoustic pressure. Short duration acoustic shock waves were produced by a 20 kilovolts electric spark source and a schlieren optical method was used to visualize the incident shockfront and the reflection/diffraction patterns. Experimental results are compared to numerical simulations based on the high-order finite difference solution of the two dimensional Navier-Stokes equations.

  16. Is the Teisseyre-Tornquist Zone an ancient plate boundary of Baltica?

    NASA Astrophysics Data System (ADS)

    Mazur, Stanislaw; Mikolajczak, Mateusz; Krzywiec, Piotr; Malinowski, Michal; Buffenmyer, Vinton; Lewandowski, Marek

    2015-12-01

    The Teisseyre-Tornquist Zone (TTZ) is generally regarded as a fossil plate boundary in Europe that extends 2000 km from the Baltic Sea to the Black Sea. We used an integrated approach merging potential fields and seismic data to explore crustal architecture across the TTZ in central Poland. The aim of the study was to test whether the TTZ coincides with an early Paleozoic (Caledonian) suture formed through the closure of the Tornquist Ocean along the SW Baltica margin. The suture is presumed to separate the East European Craton (EEC) from the Paleozoic terranes of Western Europe. Two seismic reflection lines from the PolandSPAN™ experiment were used to image the deep structure at the SW margin of the EEC. Lines PL-5300 and PL-5400 run NE-SW in central and northern Poland, respectively. The seismic interpretation down to top of basement was integrated with 2-D gravity and magnetic modeling to highlight the structure of the deep crust. Both the gravity and magnetic models show a suture that welds together two blocks at the base of crust. However, top of basement above the suture dips uniformly to the SW and is overlain by undisturbed lower Paleozoic and younger sediments. By implication, the suture must have developed in the Precambrian and both crustal blocks amalgamated belong to the EEC. Consequently, the Caledonian suture, formed by the closure of the Tornquist Ocean between Avalonia and Baltica, must be located farther southwest beneath thick upper Paleozoic and Mesozoic sediments.

  17. Virology Experts in the Boundary Zone Between Science, Policy and the Public: A Biographical Analysis

    PubMed Central

    2010-01-01

    This article aims to open up the biographical black box of three experts working in the boundary zone between science, policy and public debate. A biographical-narrative approach is used to analyse the roles played by the virologists Albert Osterhaus, Roel Coutinho and Jaap Goudsmit in policy and public debate. These figures were among the few leading virologists visibly active in the Netherlands during the revival of infectious diseases in the 1980s. Osterhaus and Coutinho in particular are still the key figures today, as demonstrated during the outbreak of novel influenza A (H1N1). This article studies the various political and communicative challenges and dilemmas encountered by these three virologists, and discusses the way in which, strategically or not, they handled those challenges and dilemmas during the various stages of the field’s recent history. Important in this respect is their pursuit of a public role that is both effective and credible. We will conclude with a reflection on the H1N1 pandemic, and the historical and biographical ties between emerging governance arrangements and the experts involved in the development of such arrangements. PMID:20676213

  18. A continuous transect through the lower seismogenic zone of a transform boundary: The Pofadder Shear Zone, Namibia and South Africa

    NASA Astrophysics Data System (ADS)

    Melosh, B. L.; Rowe, C. D.; Smit, L.

    2012-12-01

    The Pofadder Shear Zone (PSZ) is a ~400 km long, northwest to southeast oriented, dextral transform shear zone in southern Namibia and northwest South Africa. We present new geologic and structural data from mapped transects across the PSZ. These data demonstrate that, from the northwest toward the southeast, the PSZ narrows by 90%, retains a near vertical dip but changes in strike by 30 degrees, splays into a series of smaller shear zones, and displays a greater abundance of syn-kinematic greenschist facies minerals. Mineral stretching and aggregate lineations, measured on C surfaces, are defined by plastically deformed quartz and aligned hornblende porphyroblasts; these lineations display a polarity reversal in the northwest, no reversal in the southeast, and are folded by isoclinal folds. Within the mylonitic fault rock quartz, alkali feldspar and plagioclase feldspar record plastic, semi-plastic, and brittle deformation textures, respectively. Lastly, we observe monolithologic mylonite clast breccia and calc-schist cataclasites in foliation-parallel, tabular zones 1 - 50 cm thick. We interpret these data to suggest that: 1) the PSZ is tilted toward the southeast about a horizontal axis and this rotation caused differential exhumation from upper greenschist facies conditions, in the southeast, to amphibolite facies conditions, in the northwest, exposing the quartz brittle-plastic transition and the base of the seismogenic zone. Using approximate temperature estimates of these metamorphic conditions and assuming a geothermal gradient ranging between 25 - 30 °C/km we estimate the PSZ has been tilted by 17 - 11 degrees, respectively; 2) a series of discrete splay faults (possible horsetail faults) occurs on the southern side of the PSZ toward the southeast terminus where the fault approaches its tip; 3) horizontal mineral stretching lineations dominate the narrower shear zones in the southeast; and 4) fault breccias and cataclasites record either high strain rate

  19. Jupiter's Belt-Zone Boundary in Near-Infrared and Violet Light

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Mosaics of a belt-zone boundary near Jupiter's equator in violet (top panel) and near-infrared (bottom panel) light. The four images that make up each of these mosaics were taken within a few minutes of each other. Sunlight at 757 nanometers (near-infrared) penetrates deep into Jupiter's troposphere before being absorbed or scattered by clouds to the Galileo spacecraft. This wavelength reveals the features of the lower visible cloud deck. Sunlight at 415 nanometers (violet) is a scattered or absorbed to varying degrees in different parts of Jupiter's atmosphere depending on the types and concentrations of cloud particles and chemicals that color Jupiter's atmosphere. The near-infrared mosaic primarily shows cloud features. The violet mosaic has three distinct regions: it is brightest at the latitude of the jet (horizontally across the center of the mosaic), moderately bright north of the jet, and dark and patchy south of the jet.

    North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  20. Thermochronology and tectonics of the Leeward Antilles: Evolution of the southern Caribbean Plate boundary zone

    USGS Publications Warehouse

    van der Lelij, Roelant; Spikings, Richard A.; Kerr, Andrew C.; Kounov, Alexandre; Cosca, Michael; Chew, David; Villagomez, Diego

    2010-01-01

    Tectonic reconstructions of the Caribbean Plate are severely hampered by a paucity of geochronologic and exhumation constraints from anastomosed basement blocks along its southern margin. New U/Pb, 40Ar/39Ar, apatite fission track, and apatite (U-Th)/He data constrain quantitative thermal and exhumation histories, which have been used to propose a model for the tectonic evolution of the emergent parts of the Bonaire Block and the southern Caribbean Plate boundary zone. An east facing arc system intruded through an oceanic plateau during ~90 to ~87 Ma and crops out on Aruba. Subsequent structural displacements resulted in >80°C of cooling on Aruba during 70–60 Ma. In contrast, exhumation of the island arc sequence exposed on Bonaire occurred at 85–80 Ma and 55–45 Ma. Santonian exhumation on Bonaire occurred immediately subsequent to burial metamorphism and may have been driven by the collision of a west facing island arc with the Caribbean Plate. Island arc rocks intruded oceanic plateau rocks on Gran Roque at ~65 Ma and exhumed rapidly at 55–45 Ma. We attribute Maastrichtian-Danian exhumation on Aruba and early Eocene exhumation on Bonaire and Gran Roque to sequential diachronous accretion of their basement units to the South American Plate. Widespread unconformities indicate late Eocene subaerial exposure. Late Oligocene–early Miocene dextral transtension within the Bonaire Block drove subsidence and burial of crystalline basement rocks of the Leeward Antilles to ≤1 km. Late Miocene–recent transpression caused inversion and ≤1 km of exhumation, possibly as a result of the northward escape of the Maracaibo Block.

  1. On the (200)-zone boundary collective mode in Al within nearly-free-electron degenerate perturbation theory

    NASA Astrophysics Data System (ADS)

    Oliveira, Luiz E.; Sturm, K.

    1984-08-01

    The Aschroft and Sturm two-band-model on the optical properties of Al is extended for finite k values and the dielectric function ɛ( k,ω) is evaluated for k parallel to the <100 > direction within nearly-free-electron degenerate perturbation theory. It is shown that a pair of (200) Bragg planes gives rise to another pole in the energy loss function Im[-1/ɛ( k,ω)] and hence to a collective mode which is of the same origin as the so-called zone boundary collective mode first proposed by Foo and Hopfield in Na. The dispersion and the strength of this (200)-zone boundary collective mode in Al are evaluated along the <100 > direction and the theoretical results agree very well with electron energy loss spectroscopy data. Comparison is also made with a numerical calculation by Singhal for some discrete k-values.

  2. Influences of solid/liquid boundary layer thickness and tilting angle on zone-refinement of germanium crystals

    NASA Astrophysics Data System (ADS)

    Yang, Gang; Guan, Yutong; Mei, Hao; Wang, Guojian; Mei, Dongming

    In zone-refining of metals, solid/liquid (S/L) boundary layer thickness has an influence on segregation coefficient of impurity atoms. Additionally, the segregation of impurity elements during zone refining can be maximized by adjusting the zone refinement tube with a proper angle. In this paper, we report the influences of S/L boundary layer thickness on the segregation coefficients of boron, phosphor, aluminum and gallium, which have been identified as four main impurities in germanium crystal by Photothermal Ionization Spectroscopy (PTIS). The thickness of S/L boundary layer was found by using a well-known model to fit the experimental data. The optimized segregation coefficients have been used to calculate the impurity distribution along the purified ingot. In addition, we have also optimized the tilting angle of the germanium ingot to investigate the impact on the segregation. This work is supported by DOE grant DE-FG02-10ER46709 and the state of South Dakota.

  3. Recharge and Lateral Groundwater Flow Boundary Conditions for the Saturated Zone Site-Scale Flow and Transport Model

    SciTech Connect

    S. James

    2004-10-06

    This analysis is designed to use existing modeling and analysis results as the basis for estimated groundwater flow rates into the saturated zone (SZ) site-scale model domains, both as recharge (infiltration) at the upper boundary (water table), and as underflow at the lateral boundaries. Specifically, this work compiles information on the recharge boundary conditions supplied to the base-case and alternate SZ site-scale flow models taken from (1) distributed recharge from the 1997 (D'Agnese et al. 1997 [DIRS 100131]) or 2001 (D'Agnese et al. 2002 [DIRS 158876]) SZ regional-scale (Death Valley Regional Flow System [DVRFS]) model; (2) recharge below the area of the 1997 (Wu et al. 1997 [DIRS 156453]) or 2003 (BSC 2004 [DIRS 169861]) unsaturated zone (UZ) site-scale flow model; and (3) focused recharge along Fortymile Wash. In addition, this analysis includes extraction of the groundwater flow rates simulated by the 1997 and 2001 DVRFS models coincident with the lateral boundaries of the SZ site-scale flow models. The fluxes from the 1997 DVRFS were used to calibrate the base-case SZ site-scale flow model. The 2001 DVRFS fluxes are used in the alternate SZ site-scale flow model.

  4. Grain Boundary Character Distribution in the Heat-Affected Zone of Friction Stir-Processed AL 7075 T7

    NASA Astrophysics Data System (ADS)

    Basinger, J. A.; Adams, B. L.

    2007-06-01

    Current transmission electron microscopy (TEM) research (Cai et al., 2006) in the heat-affected zone (HAZ) of friction stir-welded Al 7075 T7 finds a correlation between precipitate-free zone (PFZ) width and grain boundary (GB) geometry. Based on these correlations, this article makes a comparison of grain boundary character distributions (GBCDs) in the HAZ and the parent metal via multisection plane five-parameter stereology. The stereology is conducted in a convenient macroscopic coordinate frame, associated with the HAZ. Further comparisons between the two microstructures are conducted relative to two-dimensional (2-D) GB network connectivity, recovered from electron backscatter diffraction (EBSD) data in each section plane. It is shown that the relative fraction of GBs of misorientation character associated with smaller PFZ size is larger in the HAZ as compared to the parent material. A commensurate decrease in the connectivity (radius of gyration) of GBs of character conducive to larger PFZ size is also found in the HAZ, relative to the parent material. Distribution of inclinations changes as a function of GB geometry. Surface area per unit volume of low-angle random (LAR) misorientations increases in the HAZ, while high-angle random (HAR) and coincident site lattice (CSL) boundaries decrease. In the case of LAR and some CSL boundaries, a reorientation occurs in which macroscopic normals of these interfaces rotate.

  5. Zongo-San Gaban zone: Eocene foreland boundary of the Central Andean orogen, northwest Bolivia and southeast Peru

    SciTech Connect

    Farrar, E.; Clark, A.H.; Kontak, D.J.; Archibald, D.A.

    1988-01-01

    Discordant muscovite and biotite K-Ar dates of samples taken in six transects through the Cordillera Oriental of southeast Peru and northwest Bolivia, combined with /sup 40/Ar//sup 39/Ar age spectra, reveal a northwest-trending, structurally cryptic, tectonothermal zone of late Eocene age (ca. 38 Ma) that overprints Triassic and older igneous and metamorphic rocks. The zone is at least 450 km long but is less than 25 km wide; temperatures along its northeast boundary are estimated to have reached 350/sup 0/C. No Paleogene magmatism has been recognized that could account for the thermal resetting of the K-Ar isotopic system. Uplift, erosion, and southwest-verging thrusting accompanied the development of this domain, which defined the foreland boundary of the orogen prior to inception of northeast-verging Andean thrusting in Miocene time. It is proposed that this tectonothermal zone, the Zongo-San Gaban zone (ZSGZ), which involves thrusting and basement shortening, is the southerly manifestation of the Incaic compressional deformation, which produced the thin-skinned Maranon thrust and fold belt (MTFB) north of the Abancay deflection of central Peru.

  6. Predicting Earthquake Occurrence at Subduction-Zone Plate Boundaries Through Advanced Computer Simulation

    NASA Astrophysics Data System (ADS)

    Matsu'Ura, M.; Hashimoto, C.; Fukuyama, E.

    2004-12-01

    In general, predicting the occurrence of earthquakes is very difficult, because of the complexity of actual faults and nonlinear interaction between them. From the standpoint of earthquake prediction, however, our target is limited to the large events that completely break down a seismogenic zone. To such large events we may apply the concept of the earthquake cycle. The entire process of earthquake generation cycles generally consists of tectonic loading due to relative plate motion, quasi-static rupture nucleation, dynamic rupture propagation and stop, and restoration of fault strength. This process can be completely described by a coupled nonlinear system, which consists of an elastic/viscoelastic slip-response function that relates fault slip to shear stress change and a fault constitutive law that prescribes change in shear strength with fault slip and contact time. The shear stress and the shear strength are related with each other through boundary conditions on the fault. The driving force of this system is observed relative plate motion. The system to describe the earthquake generation cycle is conceptually quite simple. The complexity in practical modeling mainly comes from complexity in structure of the real earth. Recently, we have developed a physics-based, predictive simulation system for earthquake generation at plate boundaries in and around Japan, where the four plates of Pacific, North American, Philippine Sea and Eurasian are interacting with each other. The simulation system consists of a crust-mantle structure model, a quasi-static tectonic loading model, and a dynamic rupture propagation model. First, we constructed a realistic 3D model of plate interfaces in and around Japan by applying an inversion technique to ISC hypocenter data, and computed viscoelastic slip-response functions for this structure model. Second, we introduced the slip- and time-dependent fault constitutive law with an inherent strength-restoration mechanism as a basic

  7. Strain modeling of attachment zones developed between brittle and ductile crust at wrenching plate boundaries

    NASA Astrophysics Data System (ADS)

    Teyssier, C.; Tikoff, B.; Weber, J.

    2001-12-01

    Using strain modeling we analyze the ductile deformation beneath rigid upper crustal blocks that rotate and translate in wrench zones. We define the zone of deformation as an "attachment zone" and assume strain continuity between the wrench shearing in the ductile crust and the horizontal shearing induced by the rotation/translation of rigid blocks. For reasonable amounts of rotation/translation of rigid blocks and reasonable thicknesses of attachment zones, the orientation and shape of the finite strain ellipsoids within attachment zones are calculated, and the orientation of planar and linear fabrics are predicted. Attachment zones beneath rotating blocks should display radiating foliation and concentric lineations; if rotation of rigid blocks is driven from below, deformation in the attachment zone is dominated by the wrench component, altering significantly the radiating and concentric patterns of foliation and lineation. Attachment zones beneath translating blocks display a wide range of foliation orientations, with steep foliations below the central part of rigid blocks, and gently dipping foliations toward the margins. Below the upper crustal strike-slip faults, foliation is shallowly dipping, strain intensity is maximum, and there is an abrupt reversal of sense of shear across a presumed discontinuity. The linear belt of greenschist-grade metamorphic rocks in Trinidad's Northern Ranges and eastern Venezuela's Paria Peninsula is a candidate for an exhumed attachment zone developed beneath translating upper crustal blocks during Neogene highly oblique convergence between the Caribbean and South America plates.

  8. Neotectonic map of Syria and some aspects of Late Cenozoic evolution of the northwestern boundary zone of the Arabian plate

    NASA Astrophysics Data System (ADS)

    Rukieh, M.; Trifonov, V. G.; Dodonov, A. E.; Minini, H.; Ammar, O.; Ivanova, T. P.; Zaza, T.; Yusef, A.; Al-Shara, M.; Jobaili, Y.

    2005-09-01

    The neotectonic map of Syria, 1:500,000, was compiled by the authors in 2003-2004. The map shows tectonic features formed or continued to develop during the Neogene and Quaternary in Syria and adjacent territories, including the Mediterranean realm. The neotectonic structure of the region was formed as a result of three phases of deformation. During the Early Miocene first phase, the Arabian plate moved along the Dead Sea-Jordan segments of the Levant (Dead Sea) transform fault zone, Roum fault and its continuation in the continental slope of the Mediterranean. The chain of the coastal anticlines in the "Arabian" side of the transform zone and the Lattaqie oblique (sinistral-thrust) boundary fault zone in the north were formed under the NNW-trending compression. The Lattaqie zone continued by the Cyprus arc in the west and by the Taurus (Bitlis) thrust in the east and further by the Main Thrust of the Zagros. After "quiet" (for Syria) epoch of the Middle Miocene when the Arabian plate moved to the NE, during the Late Miocene second phase of deformation, the Arabian plate moved again to the NNW along the same transform boundary. But a part of the Late Miocene plate motion (up to 20 km) resulted by shortening in the Anti-Leban-Palmyride fold-thrust belt that separated the Aleppo block from the main part of the Arabian plate. During the Pliocene-Quaternary third phase of deformation, the recent structural pattern of the Levant zone was formed in Lebanon and the northwestern Syria. At the same time, the Serghaya and smaller sinistral faults branched out the Levant zone and the system of the W-E-trending convex to the south dextral faults ruptured the Palmyrides and the stable part of the Arabian plate. The total Pliocene-Quaternary sinistral offset on the young Levant zone segments and the associated faults has reached 35-40 km, like on the Dead Sea-Jordan segments of the Levant fault zone. The faults, demonstrating the Pliocene-Quaternary activity are still active now

  9. Non-local sub-characteristic zones of influence in unsteady interactive boundary-layers

    NASA Technical Reports Server (NTRS)

    Rothmayer, A. P.

    1992-01-01

    The properties of incompressible, unsteady, interactive, boundary layers are examined for a model hypersonic boundary layer and internal flow past humps or, equivalently, external flow past short-scaled humps. Using a linear high frequency analysis, it is shown that the domains of dependence within the viscous sublayer may be a strong function of position within the sublayer and may be strongly influenced by the pressure displacement interaction, or the prescribed displacement condition. Detailed calculations are presented for the hypersonic boundary layer. This effect is found to carry over directly to the fully viscous problem as well as the nonlinear problem. In the fully viscous problem, the non-local character of the domains of dependence manifests itself in the sub-characteristics. Potential implications of the domain of dependence structure on finite difference computations of unsteady boundary layers are briefly discussed.

  10. A new mechanism for fluid migration in midcrustal shear zones based on viscous grain boundary sliding and creep cavitation

    NASA Astrophysics Data System (ADS)

    Fusseis, F.; Regenauer-Lieb, K.; Liu, J.

    2009-04-01

    The common perception of fluid migration pathways in midcrustal shear zones relies mostly on hydraulic fractures forming by tensile failure where pore fluid pressure equalizes the combined lithostatic pressure and the tensile strength of the rock. Where the associated pervasive fracturing on multiple scales does not occur but the presence of a fluid phase is indicated, different models are needed to explain fluid transfer. Here we present the ‘granular fluid pump', a model that is capable of explaining fluid migration in fine-grained ultramylonites typical for midcrustal shear zones. We investigated the porosity evolution across the margin of a shear zone in central Australia that formed in granitic gneiss at upper-greenschist facies conditions (Fliervoet et al., 1997). The strain gradient in the sample, which is macroscopically expressed by the reorientation of a preexisting foliation and a substantial grain size reduction, is interpreted as a proxy for time. Our investigation showed that the microstructural evolution of the sample is characterized by two major processes: a) The progressive reduction in abundance and size of potassium feldspar and plagioclase clasts, which decay, with increasing strain, in hydration reactions to form a fine-grained (<25 microns) ultramylonitic matrix composed of secondary potassium-feldspar, quartz, muscovite, biotite and epidote. b) The nucleation of secondary phases (mostly potassium-feldspar) at triple junctions in monomineralic quartz ribbon bands, which characterize the low-strain fabric in the rock. Both processes involve an aqueous fluid phase. Fliervoet et al. (1997) identified the feldspar reaction as the dominant strain softening process. Where the multiphase matrix forms an interconnected framework a transition in the dominant deformation mechanism occurs, from dislocation creep to a combination of viscous grain boundary sliding and pressure solution/precipitation. Our Synchrotron radiation microtomographic study

  11. Stress triggering of the great Indian Ocean strike-slip earthquakes in a diffuse plate boundary zone

    NASA Astrophysics Data System (ADS)

    Wiseman, Kelly; Bürgmann, Roland

    2012-11-01

    On April 11, 2012, two great magnitude 8+ earthquakes occurred within a two-hour period off the west coast of northern Sumatra, Indonesia, in the broadly distributed India-Australia plate boundary zone. The magnitude 8.6 mainshock holds the distinction of being both the largest instrumentally recorded strike-slip earthquake and the largest earthquake away from a recognized plate boundary fault. The mainshock involved sequential ruptures of multiple fault planes oriented nearly perpendicular to each other. The adjacent 2004 megathrust earthquake statically loaded the northern Wharton Basin oceanic lithosphere on both of the 2012 mainshock fault plane orientations, and greatly enhanced the rate of earthquake activity in the region for a year. Viscoelastic relaxation of the asthenosphere following the 2004 and 2005 megathrust earthquakes continued to positively stress the offshore region, correlating with the locations of later strike-slip earthquakes, including two magnitude 7+ and the 2012 magnitude 8+ earthquakes.

  12. Effect of boron segregation at grain boundaries on heat-affected zone cracking in wrought INCONEL 718

    NASA Astrophysics Data System (ADS)

    Chen, W.; Chaturvedi, M. C.; Richards, N. L.

    2001-04-01

    Susceptibility to heat-affected zone (HAZ) cracking during electron-beam welding was studied in two INCONEL 718-based alloys doped with different levels of boron. By lowering the carbon, sulfur, and phosphorous concentrations to be “as low as possible,” the occurrence of HAZ cracking was related directly to the level of segregation of boron at grain boundaries, which occurred by nonequilibrium segregation during a preweld heat treatment. The study has demonstrated a direct correlation between the amount of boron segregated at grain boundaries and their susceptibility to HAZ cracking, in terms of the total crack length and number of cracks observed in the HAZ. The analysis of results suggests that both the melting and resolidification temperatures of the boron-segregated grain boundaries can be about 100 °C to 200 °C lower than those of the grain boundaries that were susceptible to constitutional liquation of Nb carbides on them, making boron more deleterious in causing HAZ cracking.

  13. STRIKE SLIP ON REACTIVATED TRIASSIC(? ) BASIN BOUNDARY FAULT ZONES AS SOURCES OF EARTHQUAKES NEAR CHARLESTON, S. C.

    USGS Publications Warehouse

    Behrendt, John C.; Yuan, Annette

    1986-01-01

    Interpretation of several thousand kilometers of multifold seismic reflection data supports the old theory that earthquakes in the Charleston, S. C. area are associated with reactivated Triassic(? ) basin boundary extensional fault zones. The Gants-Cooke fault zone associated with the Jedburg basin in the 1886 meizoseismal area, an unnamed fault along the margin of the Branchville basin in the Bowman earthquake area and the offshore Helena Banks fault zone (no observed seismicity) along the margin of the Kiawah basin show evidence of reactivation of Triassic(? ) normal faults zones in a compressional, probably strike slip sense. The previously reported reverse separation of these faults observed on the seismic profiles in the late Cretaceous-Cenozoic Coastal Plain sediments is possibly produced by oblique slip with the horizontal component possibly 10 to 100 times the vertical. Earthquake recurrence intervals of several thousand years reported in the Charleston area appear consistent with ranges of magnitude of strike slip displacement inferred from the seismic reflection data, and are constrained by aeromagnetic data.

  14. Thinking and Meddling with Boundaries: Critical Reflections on Matthew Weinstein's Narrative of Street Medics, Red-Zones and Glop

    ERIC Educational Resources Information Center

    Alsop, Steve

    2015-01-01

    In pursuit of more mindful notions of hybridity, this review essay provides a series of reflections on Mathew Weinstein's representations of Street Medics and "sciences for the red zones of neoliberalism". My analysis draws on three popular ways of thinking with boundaries to offer a critical reading of the boundary-work that the…

  15. Interdependence of character of grain boundaries, intergranular segregation of boron and grain boundary liquation in simulated weld heat-affected zone in Inconel 718

    SciTech Connect

    Guo, H.; Chaturvedi, M.C.; Richards, N.L.; McMahon, G.S.

    1999-01-08

    Intergranular microfissuring is frequently observed in the weld heat-affected zones (HAZ) in Inconel 718. Extensive studies of this phenomenon have established that the HAZ microfissuring in Inconel 718 is associated with the constitutional liquation of grain boundary (GB) precipitates of carbides, Laves and {delta} phases. In addition, HAZ microfissuring has been also attributed to the GB segregation of B and S. To differentiate between the influence of B from other factors, studies were initiated on Inconel 718 that was almost free of C, P, and S, and contained different concentrations of B. These studies have shown that B in Inconel 718 can segregate to the grain boundaries by a non-equilibrium mechanism during cooling from the pre-weld solution heat treatment temperature, which would lower the melting temperature of the GB material. If the segregation of B is sufficiently high, the GBs are likely to liquate in the HAZ during the heating component of the welding thermal cycle. The inability of the liquated GBs to support tensile stresses that develop during cooling of the welds would result in microfissuring in the HAZs. It was also observed that the GB liquation in the HAZs was heterogeneously distributed. That is, while a GB liquated others connected to it did not. Therefore, an investigation was initiated to determine the interdependence of segregation of B on GBs, their crystallographic character and liquation. The results are presented in this communication.

  16. 49 CFR 71.5 - Boundary line between eastern and central zones.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... County; thence west along the north line of Pulaski County to the east line of Jasper County; thence south along the east line of Jasper County to the south line of Jasper County; thence west along the south lines of Jasper and Newton Counties to the western boundary of the State of Indiana; thence...

  17. 49 CFR 71.5 - Boundary line between eastern and central zones.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... County; thence west along the north line of Pulaski County to the east line of Jasper County; thence south along the east line of Jasper County to the south line of Jasper County; thence west along the south lines of Jasper and Newton Counties to the western boundary of the State of Indiana; thence...

  18. 49 CFR 71.5 - Boundary line between eastern and central zones.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... County; thence west along the north line of Pulaski County to the east line of Jasper County; thence south along the east line of Jasper County to the south line of Jasper County; thence west along the south lines of Jasper and Newton Counties to the western boundary of the State of Indiana; thence...

  19. 49 CFR 71.5 - Boundary line between eastern and central zones.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... County; thence west along the north line of Pulaski County to the east line of Jasper County; thence south along the east line of Jasper County to the south line of Jasper County; thence west along the south lines of Jasper and Newton Counties to the western boundary of the State of Indiana; thence...

  20. 49 CFR 71.5 - Boundary line between eastern and central zones.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... County; thence west along the north line of Pulaski County to the east line of Jasper County; thence south along the east line of Jasper County to the south line of Jasper County; thence west along the south lines of Jasper and Newton Counties to the western boundary of the State of Indiana; thence...

  1. What's so critical about the critical zone?: New insights at the boundaries between hydrology, pedology, geomorphology, rocks and life (Invited)

    NASA Astrophysics Data System (ADS)

    Grant, G.

    2013-12-01

    The great promise of critical zone science and observatories (CZOs) emerging over the past decade was that real progress towards understanding the earth's near-surface environment could be made through coordinated studies of processes and interactions that occur within that thin layer between the bottom of the atmosphere and the top of competent bedrock - the critical zone. How well has this promise been realized, and where is the science now headed? Drawing on recent findings from CZOs and elsewhere, I identify a number of exciting and potentially transformative new ideas and threads at the boundaries of hydrology, geomorphology, pedology, and ecology. These include: 1). New understanding of interactions and feedbacks among soil weathering, pathways for water, tree roots, and bedrock fractures. A fundamental insight emerging from critical zone studies is that soils are far more interestingly structured than simple textbook models of homogeneous substrates with exponentially decreasing permeability with depth. Instead, the near-surface is now seen as a complex network of voids, paths, conduits, and storage zones that are both formed and exploited by the movement of water, geochemical reactions, and organisms. This evolving perspective on the critical zone has implications for a wide range of issues, including the residence time and chemistry of water, rates of weathering, slope stability, and long-term soil fertility. 2. Growing appreciation for the role of biology in conditioning and transforming its own physical environment within the critical zone. This includes the role of trees in hydraulically redistributing water, fracturing bedrock, and contributing to long-term soil erosion and landscape evolution through tree fall and throw and vegetation effects on moisture regimes. 3. Similarly, the importance of understanding linkages among soils, water, and vegetation has never been greater as a warming climate dramatically changes the 'rules of the game'. New

  2. Angular selection of incident waves by photonic crystals with position-varying Dirac points at the Brillouin zone boundary

    NASA Astrophysics Data System (ADS)

    Xu, Changqing; Fang, Anan; Chu, Hongchen; Luo, Jie; Chan, C. T.; Hang, Zhi Hong; Lai, Yun

    2016-06-01

    We demonstrate the angular selection of incident electromagnetic waves using photonic crystals (PCs) composed of a square lattice of dielectric rods which exhibit position-varying Dirac conical dispersion at the Brillouin zone boundary. At the frequency of the Dirac point, the transmittance can reach unity at a particular incident angle associated with the Dirac dispersion, while for all other incident angles the waves are reflected due to the existence of a directional photonic band gap. By changing the size of the dielectric rods, the position of the Dirac point at the Brillouin zone boundary is variable, which makes the unity transmission angle customizable. Interestingly, we show that such a scheme of angular selection is almost independent of the refractive index of the background medium, as long as it is not too large so that a diffraction effect emerges. By investigating the PC being sandwiched by two different types of media, we find it actually acts as an optical 0 or π phase modulator at that particular incident angle. By attaching a metasurface to the PC, angular selection in the reflection geometry can also be achieved. Our work establishes a systematic and efficient method to achieve angular selection of arbitrary incident waves based on Dirac dispersions.

  3. Radiocarbon evidence for extensive plate-boundary rupture about 300 years ago at the Cascadia subduction zone

    USGS Publications Warehouse

    Nelson, A.R.; Atwater, B.F.; Bobrowsky, P.T.; Bradley, L.-A.; Clague, J.J.; Carver, G.A.; Darienzo, M.E.; Grant, W.C.; Krueger, H.W.; Sparks, R.; Stafford, Thomas W., Jr.; Stuiver, M.

    1995-01-01

    THE Cascadia subduction zone, a region of converging tectonic plates along the Pacific coast of North America, has a geological history of very large plate-boundary earthquakes1,2, but no such earthquakes have struck this region since Euro-American settlement about 150 years ago. Geophysical estimates of the moment magnitudes (Mw) of the largest such earthquakes range from 8 (ref. 3).to 91/2 (ref. 4). Radiocarbon dating of earthquake-killed vegetation can set upper bounds on earthquake size by constraining the length of plate boundary that ruptured in individual earthquakes. Such dating has shown that the most recent rupture, or series of ruptures, extended at least 55 km along the Washington coast within a period of a few decades about 300 years ago5. Here we report 85 new 14C ages, which suggest that this most recent rupture (or series) extended at least 900 km between southern British Columbia and northern California. By comparing the 14C ages with written records of the past 150 years, we conclude that a single magnitude 9 earthquake, or a series of lesser earthquakes, ruptured most of the length of the Cascadia subduction zone between the late 1600s and early 1800s, and probably in the early 1700s.

  4. ROSSBY WAVE INSTABILITY AT DEAD ZONE BOUNDARIES IN THREE-DIMENSIONAL RESISTIVE MAGNETOHYDRODYNAMICAL GLOBAL MODELS OF PROTOPLANETARY DISKS

    SciTech Connect

    Lyra, Wladimir; Mac Low, Mordecai-Mark E-mail: mordecai@amnh.org

    2012-09-01

    It has been suggested that the transition between magnetorotationally active and dead zones in protoplanetary disks should be prone to the excitation of vortices via Rossby wave instability (RWI). However, the only numerical evidence for this has come from alpha disk models, where the magnetic field evolution is not followed, and the effect of turbulence is parameterized by Laplacian viscosity. We aim to establish the phenomenology of the flow in the transition in three-dimensional resistive-magnetohydrodynamical models. We model the transition by a sharp jump in resistivity, as expected in the inner dead zone boundary, using the PENCIL CODE to simulate the flow. We find that vortices are readily excited in the dead side of the transition. We measure the mass accretion rate finding similar levels of Reynolds stress at the dead and active zones, at the {alpha} Almost-Equal-To 10{sup -2} level. The vortex sits in a pressure maximum and does not migrate, surviving until the end of the simulation. A pressure maximum in the active zone also triggers the RWI. The magnetized vortex that results should be disrupted by parasitical magneto-elliptic instabilities, yet it subsists in high resolution. This suggests that either the parasitic modes are still numerically damped or that the RWI supplies vorticity faster than they can destroy it. We conclude that the resistive transition between the active and dead zones in the inner regions of protoplanetary disks, if sharp enough, can indeed excite vortices via RWI. Our results lend credence to previous works that relied on the alpha-disk approximation, and caution against the use of overly reduced azimuthal coverage on modeling this transition.

  5. Computation of the transient flow in zoned anisotropic porous media by the boundary element method

    NASA Astrophysics Data System (ADS)

    Bruch, E.; Grilli, S.

    Results on the application of the BEM to transient two-dimensional flows in zoned anisotropic porous media are presented, including the iterative calculation of the free surface seepage position. The classical BEM equations are discretized by linear, quadratic, or cubic elements, employing special singular numerical quadrature rules. The method is improved by the incorporation of a subregion division. The present technique is shown to be very accurate and to avoid previously encountered oscillation problems.

  6. Visualizing Life Zone Boundary Sensitivities Across Climate Models and Temporal Spans

    SciTech Connect

    Sisneros, Roberto R; Huang, Jian; Ostrouchov, George; Hoffman, Forrest M

    2011-01-01

    Life zones are a convenient and quantifiable method for delineating areas with similar plant and animal communities based on bioclimatic conditions. Such ecoregionalization techniques have proved useful for defining habitats and for studying how these habitats may shift due to environmental change. The ecological impacts of climate change are of particular interest. Here we show that visualizations of the geographic projection of life zones may be applied to the investigation of potential ecological impacts of climate change using the results of global climate model simulations. Using a multi-factor classification scheme, we show how life zones change over time based on quantitative model results into the next century. Using two straightforward metrics, we identify regions of high sensitivity to climate changes from two global climate simulations under two different greenhouse gas emissions scenarios. Finally, we identify how preferred human habitats may shift under these scenarios. We apply visualization methods developed for the purpose of displaying multivariate relationships within data, especially for situations that involve a large number of concurrent relationships. Our method is based on the concept of multivariate classification, and is implemented directly in VisIt, a production quality visualization package.

  7. In-Situ Observations of Earthquake-Driven Fluid Pulses within the Japan Trench Plate Boundary Fault Zone

    NASA Astrophysics Data System (ADS)

    Fulton, P. M.; Brodsky, E. E.

    2014-12-01

    Fault valving and transient fluid flow has long been suspected to be an important process in the earthquake cycle, but has not previously been captured by direct measurements during an episode. In particular, earthquakes are thought to drive fluids in fault zones, but again, evidence has been limited to the geologic record. Here we report on the signature of fluid pumping events inside the Tohoku Fault associated with individual earthquakes. As part of the Japan Trench Fast Drilling Project (JFAST), a sub-seafloor temperature observatory was installed across the plate boundary fault zone that ruptured during the 2011 Mw 9.0 Tohoku-oki earthquake. The observatory consisted of 55 autonomous temperature sensing dataloggers extending up to 820 m below sea floor at a water depth of ~7 km. The temporary deployment recorded data from July 2012 through April 2013. In addition to measuring the frictional heat signal from the megathrust earthquake, the high-resolution temperature time series data reveal spatially coherent temperature transients following regional earthquakes. Temperature increases vertically upwards from a fracture zone and decreases downwards, which is consistent with the expected signature of a pulse entering the annulus from the fracture zone. The anomalies are a few hundredths of degree Celsius and occur repeatedly at depths that are independently interpreted to have higher fracture permeability. High-pass filtered data are spatially correlated in areas disturbed by transient fluid advection. Fluid pulses occur in response to over a dozen local earthquakes, including a Mw 5.4 on 14 October 2012, a Mw 5.5 on 11 November 2012, and a doublet of two very local Mw 7.2 intraplate earthquakes on 7 December 2012, along with its associated aftershocks. There does not appear to be a response to large far-field earthquakes such as the 28 October 2012 Mw 7.8 Haida Gwaii or 6 February 2013 Mw 8.0 Santa Cruz Islands earthquakes. These measurements provide the first in

  8. Lithosphere - asthenosphere boundary (LAB) around the Trans-European Suture Zone (TESZ)

    NASA Astrophysics Data System (ADS)

    Plomerova, J.; Babuska, V.; Vecsey, L.; Passeq Working Group

    2012-04-01

    Exploiting the long memory of the deep continental lithosphere fabric, we present the LAB as a transition between a fossil anisotropy in the lithospheric mantle and an underlying seismic anisotropy related to the present-day flow in the asthenosphere. A uniform updated model of the European LAB, recalculated from data collected during several regional studies of seismic anisotropy and other tomographic experiments (Plomerova and Babuska, 2010) is complemented by LAB depth estimates from the PASSEQ (2006-2008) field measurements, involving about 17 countries (Wilde-Piorko et al., SGG 2008). Analysis of static terms of teleseismic P-wave travel time deviations shows that the LAB topography is more distinct beneath the Phanerozoic part of Europe than beneath its Precambrian part and deepens down to ~220 km beneath the two Alpine roots, the South Carpathians and eastward of the Trans-European Suture Zone (TESZ), being shallowest beneath basins. The TESZ represents a distinct tectonic feature, which can be traced from north-western to south-eastern Europe in various seismic velocity tomography as well as in seismic anisotropy (Babuska et al., PAGEOPH 1998). Modelling seismic anisotropy around the western part of TESZ (Plomerova et al., Tectonophysics 2002; Babuska and Plomerova, Terra Nova 2004) delimited there three lithospheric domains of different thickness and fabrics: (1) thick Fennoscandian lithosphere north of the TESZ, (2) the sharply bounded fragment of a thinner lithosphere between the northern (Sorgenfrei-Tornquist Zone) and southern branch (Thor Suture) of the TESZ; (3) south of the TESZ, a domain belonging to a very thin lithosphere of Avalonia. Structure of the mantle around the Teisseyere-Tornquist Zone (TT), i.e., in the central part of the TESZ, is one of the main targets of the PASSEQ seismic experiment. The suture appears there as a broad transition zone on the surface and in the mantle it separates the thick lithosphere domains of the Paleozoic

  9. Plate boundary forces in the vicinity of Trinidad-the-transition from transpression to transtension in the Southern Caribbean plate boundary zones

    SciTech Connect

    Algar, S.T.; Pindell, J.L. )

    1993-02-01

    Deformation in the southern Caribbean plate boundary zones as recorded in the Northern Range of Trinidad initiated in the Oligocene with northward vergent gravity sliding of Northern Range sediments due to uplift and oversteepening of the previously passive margin by the eastward migration of the Caribbean flexural forebulge. Progressive east-southeast transvergence of the Caribbean Plate with respect to South America overthrust incorporated the Northern Range sediments into the Caribbean accretionary prism, thrusting them south-southeast to produce a Middle Miocene transpressive foreland fold and thrust belt in southern Trinidad. Late Miocene deformation within Trinidad was increasingly dominated by right-lateral strike-slop (RLSS) faulting, at the expense of transpressive compressional features. Right-stepping of RLSS motion initiated the Gulf of Paria and Caroni pull-apart basins, Since Early Pliocene these basins and other areas to the north of Trinidad have undergone north-south extension in addition to east-west trending RLSS. Such extension caused the northward withdrawal of Caribbean terranes from atop of the Northern Range, Resulting in rapid isostatically induced uplift (approximately 0.5 mmyr[sup -1]). This change in deformation style may relate to a hitherto unrecognized shift in the relative motion of the eastern Caribbean Plate with respect to South America: from east-southeast-directed transpression to east-northeast-directed transtension.

  10. Effect of Close-Packed Plane Boundaries in a Bain Zone on the Crack Path in Simulated Coarse-Grained HAZ of Bainitic Steel

    NASA Astrophysics Data System (ADS)

    Terasaki, Hidenori; Shintome, Yutaro; Komizo, Yu-ichi; Ohata, Mitsuru; Moriguchi, Koji; Tomio, Yusaku

    2015-05-01

    Global effect of Bain-zone boundaries and the local effect of close-packed plane (CP) boundaries on the path of secondary cleavage cracks (observed on a fractured V-notch Charpy specimen) were visualized and discussed in simulated coarse-grained HAZ of bainitic steel. Microstructural unit map (Bain-zone map and CP map) was obtained by electron backscatter diffraction method for a prior austenite grain of a few hundred micrometers. Furthermore, a correlation between CP boundaries and sites that favored formation of the blocky martensite-austenite (M-A) constituent was confirmed. It was clarified that two crack deviation/local changing factors (CP boundaries and blocky M-A) are paired.

  11. Correlated observations of the boundary between polar cap and nightside auroral zone by HF radars and the DMSP satellite

    SciTech Connect

    Senior, C.; Cerisier, J.C. ); Hanuise, C. ); Villain, J.P. ); Greenwald, R.G.; Newell, P.T. ); Rich, F.J. )

    1994-02-01

    Simultaneous observations from HF radars and the DMSP satellite have been used to relate the ionospheric convection pattern and the nightside precipitation at the polar cap-auroral zone boundary. The convection is eastward in the poleward part of the radars field of view and predominantly westward at lower latitudes. The DMSP-F9 particle spectrograms exhibit energetic precipitating protons at the poleward edge of an inverted V'. The downward H[sup +] flow displays spatial filtering effects with a clear energy-latitude dispersion. Single-particle trajectory simulations in appropriate field models demonstrate that these ions were ejected from the neutral sheet near 120 R[sub E] geocentric distance. Most notably, the simulations reveal significant azimuthal dispersion during transport, and the source region in the magnetotail is found to extend over several Earth radii in the dawn-dusk direction, less energetic particles originating duskward of the high-energy ones. The longitudinal spread of the tail source suggests particle precipitation in the ionosphere over at least one hour magnetic local time. Also, as the downflowing protons travel near the lobeward edge of the plasma sheet, the observations suggest that the convection reversal lies inside the boundary layer plasma sheet (PSBL). 11 refs., 3 figs.

  12. Geothermal Frontier: Penetrate a boundary between hydrothermal convection and heat conduction zones to create 'Beyond Brittle Geothermal Reservoir'

    NASA Astrophysics Data System (ADS)

    Tsuchiya, N.; Asanuma, H.; Sakaguchi, K.; Okamoto, A.; Hirano, N.; Watanabe, N.; Kizaki, A.

    2013-12-01

    EGS has been highlightened as a most promising method of geothermal development recently because of applicability to sites which have been considered to be unsuitable for geothermal development. Meanwhile, some critical problems have been experimentally identified, such as low recovery of injected water, difficulties to establish universal design/development methodology, and occurrence of large induced seismicity. Future geothermal target is supercritical and superheated geothermal fluids in and around ductile rock bodies under high temperatures. Ductile regime which is estimated beyond brittle zone is target region for future geothermal development due to high enthalpy fluids and relatively weak water-rock interaction. It is very difficult to determine exact depth of Brittle-Ductile boundary due to strong dependence of temperature (geotherm) and strain rate, however, ductile zone is considered to be developed above 400C and below 3 km in geothermal fields in Tohoku District. Hydrothermal experiments associated with additional advanced technology will be conducting to understand ';Beyond brittle World' and to develop deeper and hotter geothermal reservoir. We propose a new concept of the engineered geothermal development where reservoirs are created in ductile basement, expecting the following advantages: (a)simpler design and control the reservoir, (b)nearly full recovery of injected water, (c)sustainable production, (d)cost reduction by development of relatively shallower ductile zone in compression tectonic zones, (e)large quantity of energy extraction from widely distributed ductile zones, (f)establishment of universal and conceptual design/development methodology, and (g) suppression of felt earthquakes from/around the reservoirs. In ductile regime, Mesh-like fracture cloud has great potential for heat extraction between injection and production wells in spite of single and simple mega-fracture. Based on field observation and high performance hydrothermal

  13. YOUNG STELLAR OBJECT SEARCH TOWARD THE BOUNDARY OF THE CENTRAL MOLECULAR ZONE WITH NEAR-INFRARED POLARIMETRY

    SciTech Connect

    Yoshikawa, Tatsuhito; Nagata, Tetsuya; Nishiyama, Shogo; Kwon, Jungmi; Tamura, Motohide E-mail: nagata@kusastro.kyoto-u.ac.jp

    2014-08-01

    We have carried out near-infrared polarimetry toward the boundary of the Central Molecular Zone, in the field of (–1.°4 ≲ l ≲ –0.°3 and 1.°0 ≲ l ≲ 2.°9, |b| ≲ 0.°1), using the near-infrared polarimetric camera SIRPOL on the 1.4 m Infrared Survey Facility telescope. We have selected 112 intrinsically polarized sources on the basis of the estimate of interstellar polarization on Stokes Q/I – U/I planes. The selected sources are brighter than K{sub S} = 14.5 mag and have polarimetric uncertainty δP < 1%. Ten of these distinctive polarized sources are fit well with spectral energy distributions of young stellar objects when using the photometry in the archive of the Spitzer Space Telescope mid-infrared data. However, many sources have spectral energy distributions of normal stars suffering from heavy interstellar extinction; these might be stars behind dark clouds. Due to the small number of distinctive polarized sources and candidates of young stellar objects, we cannot judge if they are declining in number outside the Central Molecular Zone. Many massive candidates for young stellar objects in the literature have only small intrinsic polarization. This might suggest that their masses are 4-15 M {sub ☉}, whose intrinsic polarization has been expected to be small.

  14. Thermochronometrically constrained anatomy and evolution of a Miocene extensional accommodation zone and tilt domain boundary: The southern Wassuk Range, Nevada

    NASA Astrophysics Data System (ADS)

    Gorynski, Kyle E.; Stockli, Daniel F.; Douglas Walker, J.

    2013-06-01

    (AHe) and Zircon (ZHe) (U-Th)/He thermochronometric data from the southern Wassuk Range (WR) coupled with 40Ar/39Ar age data from the overlying tilted Tertiary section are used to constrain the thermal evolution of an extensional accommodation zone and tilt-domain boundary. AHe and ZHe data record two episodes of rapid cooling related to the tectonic exhumation of the WR fault block beginning at ~15 and ~4 Ma. Extension was accommodated through fault-block rotation and variably tilted the southern WR to the west from ~60°-70° in the central WR to ~15°-35° in the southernmost WR and Pine Grove Hills, and minimal tilting in the Anchorite Hills and along the Mina Deflection to the south. Middle Miocene geothermal gradient estimates record heating immediately prior to large-magnitude extension that was likely coeval with the extrusion of the Lincoln Flat andesite at ~14.8 Ma. Geothermal gradients increase from ~19° ± 4°C/km to ≥ 65° ± 20°C/km toward the Mina Deflection, suggesting that it was the focus of Middle Miocene arc magmatism in the upper crust. The decreasing thickness of tilt blocks toward the south resulted from a shallowing brittle/ductile transition zone. Postmagmatic Middle Miocene extension and fault-block advection were focused in the northern and central WR and coincidentally moderated the large lateral thermal gradient within the uppermost crust.

  15. Seismic heating signatures in the Japan Trench subduction plate-boundary fault zone: evidence from a preliminary rock magnetic `geothermometer'

    NASA Astrophysics Data System (ADS)

    Yang, Tao; Dekkers, Mark J.; Zhang, Bo

    2016-04-01

    Frictional heating during earthquake rupture reveals important information on earthquake mechanisms and energy dissipation. The amount of annealing varies widely and is, as yet, poorly constrained. Here we use magnetic susceptibility versus temperature measurements during cycling to increasingly elevated temperatures to constrain the maximum temperature a slip zone has experienced. The case study comprises sheared clay cored from the Japan Trench subduction plate-boundary fault zone (décollement), which accommodated the large slip of the 2011 Mw 9.0 Tohoku-oki earthquake. The décollement was cored during the Integrated Ocean Drilling Program (IODP) Expedition 343, the Japan Trench Fast Drilling Project (JFAST). Heating signatures with estimated maximum temperatures ranging from ˜300 to over 500 °C are determined close to the multiple slip surfaces within the décollement. Since it is impossible to tie a specific slip surface to a certain earthquake, thermal evidence for the cumulative effect of several earthquakes is unveiled. This as yet preliminary rock magnetic `geothermometer' would be a useful tool to detect seismic heating along faults that experienced medium temperature rise, a range which is difficult to assess with other approaches.

  16. Sub-crustal earthquakes within the Australia-Pacific plate boundary zone beneath the Southern Alps, New Zealand

    NASA Astrophysics Data System (ADS)

    Boese, C. M.; Stern, T. A.; Townend, J.; Bourguignon, S.; Sheehan, A.; Smith, E. G. C.

    2013-08-01

    Sub-crustal earthquakes have been observed sporadically for ∼40 years in the central South Island of New Zealand. We report on 20 events recorded between December 2008 and February 2012 near the Alpine Fault in the continental collision zone between the Australian and Pacific plates. A subset of 18 events at depths of 47-74 km occurs south of Mt. Cook and together with recently reported tremor locations indicates along-strike variations in deformation behaviour along the plate boundary. The sub-crustal earthquakes south of Mt. Cook increase in depth, frequency and size southwards towards the Puysegur subduction zone. Focal mechanisms could be determined for 14 earthquakes and exhibit predominantly strike-slip and reverse faulting solutions. Stress inversion analysis of the focal mechanisms yields a stress field favouring oblique-reverse faulting. We interpret the geographic and vertical distributions of these sub-crustal events in relation to a previously proposed tectonic model of a remnant passive margin that formed south of New Zealand in the Eocene and was overridden when dextral strike-slip motion initiated on the Alpine Fault. We infer that sub-crustal earthquakes occur along the leading edge of this structure, which is attached to the continental Australian crust.

  17. Kinematics to dynamics in the New Zealand Plate boundary zone: implications for the strength of the lithosphere

    NASA Astrophysics Data System (ADS)

    Lamb, Simon

    2015-05-01

    New Zealand straddles the boundary between the Australian and Pacific Plate. Cenozoic relative plate motion has resulted in a complex pattern of faulting and block rotation in a zone of continental lithosphere up to 250 km wide. I investigate the implications of the short-term kinematics for the strength of the deforming lithosphere. I use a compilation of seismic reflection/refraction studies and high quality receiver function analyses to determine both the regional structure of the crust, which ranges from 20 to 50 km thick, and fields of buoyancy stress (or GPE per unit volume). Deformation over thousands of years is quantified in terms of velocity and strain rate fields, based on an inversion of neotectonic fault slip and palaeomagnetic data, in the context of the short-term relative plate motions. Forces on the subduction megathrust, as well as deviatoric stresses in the behind subduction region, are calculated from simple 2-D force balances across the Hikurangi Margin, given negligible deviatoric stresses at the along-strike transition between backarc extension and compression. Average megathrust shear stresses are in the range 6-15 MPa, and average lithospheric stresses <20 MPa in the overriding plate. The regional lithospheric strength of the plate boundary zone, assuming a viscous rheology (Newtonian or power law), is determined from an inversion of the field of gradients of buoyancy stress (averaged over either the top 25 km of the crust, or 100-km-thick lithosphere) and strain rate, using the thin sheet stress balance equations, calibrated with the subduction force balance analysis. Effective viscosities for the deforming lithosphere and/or crust are in the range 0.1-5 × 1021 Pa s, with marked weakening in zones of high strain rate, and an abrupt transition to viscosities >1022 Pa s at the margins of the rigid plates. If lateral variations in effective viscosity are only due to non-Newtonian behaviour, these data indicate a bulk power law rheology, with

  18. Rainy Lake wrench zone: An example of an Archaean subprovince boundary in northwestern Ontario

    NASA Technical Reports Server (NTRS)

    Poulsen, K. H.

    1986-01-01

    The Superior Province of the Canadian Shield comprises an alternation of subprovinces with contrasting lithological, structural and metamorphic styles. Rocks of the Rainly Lake area form a fault bounded wedge between two of these subprovinces, the Wabigoon granite-greenstone terrain to the north and the Quetico metasedimentary terrain to the south. The Quetico and Seine River-Rainy Lake Faults bound this wedge within which interpretation of the stratigraphy has been historically contentious. In the eastern part of the wedge, volcanic rocks and coeval tonalitic sills are unconformably overlain by fluviatile conglomerate and arenite of the Seine Group; in the western part of the wedge, metamorphosed wacke and mudstone of the Coutchiching Group are cut by granodioritic plutons. The Coutchiching Group has previously been correlated with the Seine Group and with the turbiditic Quetico metasediments of the Quetico Subprovince and these correlations are the cornerstone of earlier tectonic models which relate the subprovinces. The structural geology of the Rainy Lake area is characterized by attributes which compare favourably with the known characteristics of dextral wrench or 'transpressive zones based both on experimental data and natural examples. Much of this deformation involved the Seine Group, the youngest stratigraphic unit in the area, and predates the emplacement of late-to-post-tectonic granodioritic plutons for which radiometric data indicate a Late Archean age.

  19. Nanoscale Strain Fields Research of Boundaries between B2 Matrix and G.P. Zone in Ni-Ti Alloy Thin Films

    PubMed Central

    Zhao, Shilei; Zhao, Chunwang

    2014-01-01

    Ti-47at.%Ni alloy films were prepared by magnetron sputtering followed by 460°C for 40 minutes heat-treatment. The strain fields between B2 phase matrix and G.P. zone were mapped by a combination of high-resolution transmission electron microscopy and geometric phase analysis method. It was found that there is a compressive strain region parallel to the longitudinal axis of G.P. zone with 2 nm in width, −2.2% in average strain at the boundaries between B2 phase and G.P. zone. PMID:24782660

  20. Structure of the Entrainment Zone Capping the Convective Atmospheric Boundary Layer.

    NASA Astrophysics Data System (ADS)

    Sullivan, Peter P.; Moeng, Chin-Hoh; Stevens, Bjorn; Lenschow, Donald H.; Mayor, Shane D.

    1998-10-01

    The authors use large-eddy simulation (LES) to investigate entrainment and structure of the inversion layer of a clear convectively driven planetary boundary layer (PBL) over a range of bulk Richardson numbers, Ri. The LES code uses a nested grid technique to achieve fine resolution in all three directions in the inversion layer.Extensive flow visualization is used to examine the structure of the inversion layer and to illustrate the temporal and spatial interaction of a thermal plume and the overlying inversion. It is found that coherent structures in the convective PBL, that is, thermal plumes, are primary instigators of entrainment in the Ri range 13.6 Ri 43.8. At Ri = 13.6, strong horizontal and downward velocities are generated near the inversion layer because of the plume-interface interaction. This leads to folding of the interface and hence entrainment of warm inversion air at the plume's edge. At Ri = 34.5, the inversion's strong stability prevents folding of the interface but strong horizontal and downward motions near the plume's edge pull down pockets of warm air below the nominal inversion height. These pockets of warm air are then scoured off by turbulent motions and entrained into the PBL. The structure of the inversion interface from LES is in good visual agreement with lidar measurements in the PBL obtained during the Lidars in Flat Terrain field experiment.A quadrant analysis of the buoyancy flux shows that net entrainment flux (or average minimum buoyancy flux min) is identified with quadrant IV + < 0 motions, that is, warm air moving downward. Plumes generate both large negative quadrant II + < 0 and positive quadrant III > 0 buoyancy fluxes that tend to cancel.The maximum vertical gradient in potential temperature at every (x, y) grid point is used to define a local PBL height, zi(x, y). A statistical analysis of zi shows that skewness of zi depends on the inversion strength. Spectra of zi exhibit a sensitivity to grid resolution. The

  1. 3D Simulation of the Entire Process of Earthquake Generation at Subduction-Zone Plate Boundaries

    NASA Astrophysics Data System (ADS)

    Matsu'Ura, M.; Hashimoto, C.; Fukuyama, E.

    2003-12-01

    In general, the entire process of earthquake generation consists of tectonic loading due to relative plate motion, quasi-static rupture nucleation, dynamic rupture propagation and stop, and restoration of fault strength. This process can be completely described by a coupled nonlinear system, which consists of an elastic/viscoelastic slip-response function that relates fault slip to shear stress change and a fault constitutive law that prescribes change in shear strength with fault slip and contact time. The shear stress and the shear strength are related with each other through boundary conditions on the fault. The driving force of this system is observed relative plate motion. The system to describe the earthquake generation cycle is conceptually quite simple. The complexity in practical modelling mainly comes from complexity in structure of the real earth. As a product of Crustal Activity Modelling Program (CAMP), which is one of the three main programs composing the Solid Earth Simulator project (1998-2003) promoted by MEXT, we have completed a physics-based predictive simulation model for the entire process of earthquake generation cycles in and around Japan, where the four plates of Pacific, North American, Philippine Sea and Eurasian are interacting with each other in a very complicated way. The total simulation system consists of a crust-mantle structure model, a tectonic loading model and a dynamic rupture model. First, we constructed a realistic 3D standard model of plate interfaces in and around Japan by applying an inversion technique to ISC hypocenter distribution data, and computed viscoelastic slip-response functions for this structure model. Second, we introduced the slip- and time-dependent fault constitutive law with an inherent strength-restoration mechanism as a basic equation governing the entire process of earthquake generation. Third, combining all these elements, we developed a simulation model for quasi-static stress accumulation due to

  2. Along-axis variations within the plate boundary zone of the southern segment of the Endeavour Ridge

    NASA Astrophysics Data System (ADS)

    Barone, Angela M.; Ryan, William B. F.

    1988-07-01

    The width of and along-axis variations within the plate boundary zone of the southern segment of the Endeavour Ridge of the Juan de Fuca Ridge System have been quantified using Sea MARC I side-looking sonar imagery. The sonar imagery was calibrated with video and photographic surveying to provide visual corroboration of the activity, spacing, and offset of faults and fissures. This ridge segment contains an axial high bisected along its length by a summit depression whose width, relief of its rims, depth of its floor, and spacing of faults and fissures vary systematically away from the mid-point of the ridge segment toward its tips. The axial high and its summit depression are likened to an elongated shield volcano that is being disrupted by collapse of its crest into a widening linear caldera. The observed distribution of faults and fissures could be produced by mechanisms which stretch young ocean crust which is characterized by rheological properties which vary with distance from the center of the elongated volcano.

  3. Paleomagnetic Data Bearing on the Evolution of the Walker Lane Belt Transfer Zone From mid-Miocene to Present: an Investigation of the Inferred Southern and Eastern Boundaries.

    NASA Astrophysics Data System (ADS)

    Grow, J. S.; Geissman, J. W.; Oldow, J. S.

    2008-12-01

    The Walker Lane Belt (WLB) transfer zone, which initiated in the mid-Miocene, presently links the Eastern California Shear Zone (ECSZ) in the south to the Central Nevada Seismic Belt (CNSB) and WLB to the east and north, respectively. This transfer zone is part of a diffuse intracontinental deformation zone that accommodates some 25 percent of the current motion between the North American and Pacific plates. The boundary of the transfer system is clear on the northern and western margins but the extent of the system to the south and east is only inferred. The extent of deformation and development of the WLB transfer zone since the mid-Miocene is being examined by a paleomagnetic study of 125 sites that includes Miocene to mid-Pliocene volcanic and shallow intrusive rocks near the inferred southern and eastern boundaries. Results from 39 sites inside and along the southern boundary (i.e. Goldfield Hills, Montezuma Range, Clayton Ridge) show about 30° of clockwise rotation (D = 028.3°, I = 57.8°, α95 = 3.9°, discordant from the expected Neogene direction of D = 358°, I = 55°). The area where 13 of these 39 sites are located (i.e. northern Amargosa Range, eastern Slate Ridge) was previously thought to lie outside of the inferred boundary, yet it also shows about 30° of clockwise rotation (D = 031.2°, I = 52.4°, α95 = 6.7°). Areas along the eastern boundary (i.e. southern San Antonio Range) of the transfer zone are still under investigation; data obtained to date are not internally consistent. Overall, the available paleomagnetic data suggest that the southern extent of the WLB transfer zone was larger than previously expected during the mid-Miocene to mid-Pliocene, and based on previous paleomagnetic, structural, and geodetic studies of the area, support a transition from more diffuse to localized deformation (forming the Mina Deflection) at about 3 Ma.

  4. The Teisseyre-Tornquist Zone - early Palaeozoic strike-slip plate boundary or Ediacaran rifted margin of Baltica?

    NASA Astrophysics Data System (ADS)

    Mazur, Stanislaw; Krzywiec, Piotr; Malinowski, Michal; Lewandowski, Marek; Buffenmeyer, Vinton; Green, Christopher

    2016-04-01

    The Teisseyre-Tornquist Zone (TTZ) is the longest European tectonic and geophysical lineament extending from the Baltic Sea in the northwest to the Black Sea in the southeast. This tectonic feature defines a transition between the thick crust of the East European Craton (EEC) and the thinner crust of the Palaeozoic Platform to the southwest. Being a profound zone of crustal and lithospheric thickness perturbation, the TTZ has usually been considered a Caledonian tectonic suture formed due to the closure of the Tornquist Ocean. The suture was hypothesised to originate from the collision between Baltica and Avalonia or large-scale strike-slip displacement along strike of the Caledonian Orogen. However, some minority views postulated the continuation of Baltica crystalline basement farther to the southwest up to the Elbe Lineament and the margin of the Variscan Belt. We studied the ION Geophysical PolandSPAN survey that consists of 10 regional, seismic depth profiles covering the SW margin of the EEC and the TTZ in Poland. Since the PolandSPAN profiles image to ~30 km depth their interpretation was integrated with the potential fields data and earlier results of refraction sounding to better image the deep structure of the TTZ. Our data show that the NW and central sections of the TTZ correspond, at the Moho level, to a relatively narrow crustal keel and a significant Moho step at the transition from the EEC to the Palaeozoic Platform. However, top of basement above the TTZ is smooth and moderately sloping towards the southwest. In the central part of the TTZ, top of Precambrian is covered by undisturbed lower Palaeozoic sediments. In contrast, the lower Palaeozoic sediments are involved in a latest Silurian, thin-skinned fold-and-thrust belt along the NW section of the TTZ, where the sharply defined Caledonian Deformation Front adjoins a rigid basement buttress above the TTZ. Finally, the crustal keel is mostly missing from the SE section of the TTZ. Instead, this

  5. AFS controlling algorithm

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Jiang, Lanfang; Wang, Gengjie; Wang, Li

    2008-12-01

    Adaptive front lighting system (i.e., AFS) is the development trend of lighting system of motor vehicles. AFS means that headlamp can adjust beam direction to get best illumination according to road condition and its bodywork. The paper discusses the AFS key techniques: establishing calculation formulae of vehicle body state concerned road condition and steering state. Because of sensor technology limitations, it only can deal with inclination and turn of vehicle body state by means of sensor's signals. This paper studies the relationship between inclination and turn of the body and lamp lighting on the base of relative standards, and gives out the calculation formulae for the body and lamp lighting adjustment, also discusses its dynamical properties. The study is basic work for lighting adjustment automatically.

  6. The Ionian and Alfeo-Etna fault zones: New segments of an evolving plate boundary in the central Mediterranean Sea?

    NASA Astrophysics Data System (ADS)

    Polonia, A.; Torelli, L.; Artoni, A.; Carlini, M.; Faccenna, C.; Ferranti, L.; Gasperini, L.; Govers, R.; Klaeschen, D.; Monaco, C.; Neri, G.; Nijholt, N.; Orecchio, B.; Wortel, R.

    2016-04-01

    The Calabrian Arc is a narrow subduction-rollback system resulting from Africa/Eurasia plate convergence. While crustal shortening is taken up in the accretionary wedge, transtensive deformation accounts for margin segmentation along transverse lithospheric faults. One of these structures is the NNW-SSE transtensive fault system connecting the Alfeo seamount and the Etna volcano (Alfeo-Etna Fault, AEF). A second, NW-SE crustal discontinuity, the Ionian Fault (IF), separates two lobes of the CA subduction complex (Western and Eastern Lobes) and impinges on the Sicilian coasts south of the Messina Straits. Analysis of multichannel seismic reflection profiles shows that: 1) the IF and the AEF are transfer crustal tectonic features bounding a complex deformation zone, which produces the downthrown of the Western lobe along a set of transtensive fault strands; 2) during Pleistocene times, transtensive faulting reactivated structural boundaries inherited from the Mesozoic Tethyan domain which acted as thrust faults during the Messinian and Pliocene; and 3) the IF and the AEF, and locally the Malta escarpment, accommodate a recent tectonic event coeval and possibly linked to the Mt. Etna formation. Regional geodynamic models show that, whereas AEF and IF are neighboring fault systems, their individual roles are different. Faulting primarily resulting from the ESE retreat of the Ionian slab is expressed in the northwestern part of the IF. The AEF, on the other hand, is part of the overall dextral shear deformation, resulting from differences in Africa-Eurasia motion between the western and eastern sectors of the Tyrrhenian margin of northern Sicily, and accommodating diverging motions in the adjacent compartments, which results in rifting processes within the Western Lobe of the Calabrian Arc accretionary wedge. As such, it is primarily associated with Africa-Eurasia relative motion.

  7. Fault Population Analyses in the Eastern California Shear Zone: Insights into the Development of Young, Actively Evolving Plate Boundary Structures

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Dawers, N. H.; Amer, R. M.

    2014-12-01

    Relationships between cumulative fault displacement, slip rate and length, along with fault population statistics are analyzed for faults located within the Eastern California Shear Zone (ECSZ), focusing on areas north of the Garlock fault. Here many faults are geologically young and in an early stage of evolution, while many older and larger faults are also still active. We analyze scaling relationships for both strike-slip and normal faults in order to determine whether the two fault populations share the same properties or not. Cumulative displacement, slip rate and length data are collected from published maps and literature sources. The dataset spans fault lengths from tens of meters to hundreds of kilometers. Results of fault scaling analyses indicate that displacement has a linear relationship with fault length for normal faults in this area over the entire length span, whereas strike-slip faults do not have a clear displacement-length scaling relation. For a given length, the subset of strike-slip faults typically exhibits a much larger displacement than that for the normal faults. The slip rate versus length trends are similar but are considerably more scattered. In addition, we define a subpopulation of normal faults that are kinematically related to the right-lateral strike-slip faults; these have a maximum length set by the spacing between the right-lateral faults. Fault size-frequency distributions also indicate differences between the normal and strike-slip fault populations. Overall, the normal faults have higher ratios of cumulative number to fault length than the strike-slip population does, which we relate to different patterns of localization of faulting. We interpret these trends as reflecting different tectonic histories, with the majority of normal faults being intraplate faults associated with Basin and Range extension and the strike-slip faults being kinematically connected with plate boundary.

  8. The boundary between the eastern and western domains of the Pyrenean Orogen: a Cenozoic triple junction zone in Iberia?

    NASA Astrophysics Data System (ADS)

    Tavani, S.

    2012-04-01

    occurred due to the penetration of the NW-SE-striking intraplate right-lateral transpressive system of the Iberian Chain into the Cantabrian Domain of the Pyrenean Orogen. Cenozoic right-lateral reactivation of the Ubierna Fault System, in fact, is part of a NW-SE striking intraplate strike-slip transpressive system, which to the south-east includes the Iberian Chain until the Mediterranean Sea and that, in the western termination of the Ubierna Fault System, branches off into three main splay faults, which are the Ventaniella and Leon faults, and the Duero frontal thrust. Taking into account the role of this Cenozoic transpressive system allows to drastically reduce the gap between plate kinematic reconstructions and geological evidences. This implies that, despite the limited amount of displacement, the Iberian Chain and the Ubierna-Ventaniella systems must be elevated to the rank of microplate boundary, which divided two sectors of the Iberian Plate. Accordingly, the intersection between this system and the Pyrenean Orogen, which occurs in the CTA, must be regarded as a triple junction zone.

  9. Fold/cleavage relationships as indicator for late Variscan sinistral transpression at the Rheno-Hercynian-Saxo-Thuringian boundary zone, Central European Variscides

    NASA Astrophysics Data System (ADS)

    Stephan, Tobias; Kroner, Uwe; Hahn, Torsten; Hallas, Peter; Heuse, Thomas

    2016-06-01

    The boundary between the Rheno-Hercynian and the Saxo-Thuringian zones of the European Variscides is characterized by a NE-SW striking late orogenic fold-and-thrust belt affecting the intervening Rheic suture. Classical models used the first-order strike of this zone as an indicator for perpendicular plate convergence, i.e. NW-SE. We present structural data from both sides of the suture, focusing on fold-cleavage relationships. The statistical analysis reveals an orientation maximum of the youngest cleavage that deviates from the strike of the fold-and-thrust belt by c. 22°. The presence of clockwise transection of the folds by the cleavage (up to - 16°) indicates pervasive sinistral transpression. Three types of fold-cleavage relationships are observed: NE trending folds (I) with or (II) without a transecting cleavage, and (III) non-transected ENE trending folds. We explain the occurrence of different fold-cleavage types by strain partitioning due to NNW convergence obliquely to pre-existent NE trending mechanical anisotropies. In terms of plate tectonics we propose that the classical boundary of the Rheno-Hercynian and the Saxo-Thuringian Zone represents an initial transform plate boundary that was finally affected by sinistral transpression.

  10. Low Intensity Characteristic of Plate-Boundary S-S Reflections Within a Region of Strong Plate-Boundary P-P Reflections and low Seismicity Along the Japan Trench Subduction Zone

    NASA Astrophysics Data System (ADS)

    Mochizuki, K.; Kasahara, J.; Hino, R.; Nishino, M.; Yamada, T.; Shinohara, M.; Kanazawa, T.

    2003-12-01

    It has been pointed out that the epicenters of the microearthquakes along the forearc slope of the Japan Trench are not uniformly distributed but clustered in seismically active zones that are oriented perpendicular to the trench axis. One of the clear seismic-aseismic boundaries of such seismic clusters can be identified in latitude 39° N. A seismic survey was conducted in 1996 with one profile running across the boundary and parallel to the trench axis, and a P-wave velocity structure model was obtained by travel-time inversion (Fujie, 1999). A strong anti-correlation between the seismicity and the intensity of the plate-boundary P-P reflected waves was found: strong plate-boundary P-P reflected waves were observed in a region where seismicity is quite low, and vice versa (Fujie et al., 2002). They discussed that a thin layer of low P-wave velocities (3~4 km/s) with its thickness up to a few hundred meters along the plate boundary could explain the intensity of the reflections. Results of finite-difference waveform calculations support this estimation (Moghaddam, 2002). Another seismic survey was carried out in 2001 with 7 trench-parallel profiles in the same region as the 1996 survey in order to map and verify the strong anti-correlation. The strong anti-correlation was observed over the seismic-aseismic boundary region, and it was inferred that a thin layer with low P-wave velocities along the plate boundary exists beneath the aseismic zone in the region. Understanding the characteristics of plate-boundary S-S reflections in addition to those of P-P reflections would greatly help put better constraints on the physical properties along the plate boundary. Substantial P-to-S conversion at the base of the sedimentary layers was observed. S-wave velocities, especially those of the sedimentary layers, should be precisely determined in order to have good estimates of the arrival times of the plate-boundary S-S reflected waves. The S-wave velocities of the

  11. The boundary element method in the determination of the hydrodynamic field from the bladed zones of turbomachines

    NASA Astrophysics Data System (ADS)

    Anton, I.; Carte, I. N.; Ludescher, H.; Iosif, A.

    1990-04-01

    The application of the boundary element method to the analysis of axisymmetric motions is examined with particular reference to turbomachines. A procedure for determining the hydrodynamic field in the meridian plane of turbomachine blading using the boundary element method is presented. The method is applied to a Francis turbine impeller with lateral boundaries of the Bovet type. The results obtained are compared with calculations by the finite element method.

  12. Using Paleoseismic Trenching and LiDAR Analysis to Evaluate Rupture Propagation Through Segment Boundaries of the Central Wasatch Fault Zone, Utah

    NASA Astrophysics Data System (ADS)

    Bennett, S. E. K.; DuRoss, C. B.; Reitman, N. G.; Devore, J. R.; Hiscock, A.; Gold, R. D.; Briggs, R. W.; Personius, S. F.

    2014-12-01

    Paleoseismic data near fault segment boundaries constrain the extent of past surface ruptures and the persistence of rupture termination at segment boundaries. Paleoseismic evidence for large (M≥7.0) earthquakes on the central Holocene-active fault segments of the 350-km-long Wasatch fault zone (WFZ) generally supports single-segment ruptures but also permits multi-segment rupture scenarios. The extent and frequency of ruptures that span segment boundaries remains poorly known, adding uncertainty to seismic hazard models for this populated region of Utah. To address these uncertainties we conducted four paleoseismic investigations near the Salt Lake City-Provo and Provo-Nephi segment boundaries of the WFZ. We examined an exposure of the WFZ at Maple Canyon (Woodland Hills, UT) and excavated the Flat Canyon trench (Salem, UT), 7 and 11 km, respectively, from the southern tip of the Provo segment. We document evidence for at least five earthquakes at Maple Canyon and four to seven earthquakes that post-date mid-Holocene fan deposits at Flat Canyon. These earthquake chronologies will be compared to seven earthquakes observed in previous trenches on the northern Nephi segment to assess rupture correlation across the Provo-Nephi segment boundary. To assess rupture correlation across the Salt Lake City-Provo segment boundary we excavated the Alpine trench (Alpine, UT), 1 km from the northern tip of the Provo segment, and the Corner Canyon trench (Draper, UT) 1 km from the southern tip of the Salt Lake City segment. We document evidence for six earthquakes at both sites. Ongoing geochronologic analysis (14C, optically stimulated luminescence) will constrain earthquake chronologies and help identify through-going ruptures across these segment boundaries. Analysis of new high-resolution (0.5m) airborne LiDAR along the entire WFZ will quantify latest Quaternary displacements and slip rates and document spatial and temporal slip patterns near fault segment boundaries.

  13. Mapping of crustal scale tectonic boundaries in the Ossa-Morena Zone using reprocessed IBERSEIS reflection seismic data

    NASA Astrophysics Data System (ADS)

    Kashubin, A. S.; Juhlin, C.

    2010-06-01

    The IBERSEIS deep seismic reflection profile imaged crustal scale structures in the SW Iberian Variscan belt, crossing the South Portuguese Zone, the Ossa-Morena Zone and the Central Iberian Zone in Spain. Two subsets of the profile, corresponding to the South Portuguese Zone-Ossa-Morena Zone and the Ossa-Morena Zone-Central Iberian Zone tectonic contacts, have been reprocessed with the aim of investigating the influence of cross-dip and to better image steeply dipping features. Alternative strategies for binning midpoints into common depth point (CDP) bins using different azimuths were examined for synthetic data. We show that the choice of the CDP-processing line and the bin azimuth orientation has a significant impact on the normal moveout and dip-moveout velocities and is crucial to optimizing the quality of the stacked seismic image along the crooked profile. Multi-azimuth binning, normal moveout/dip-moveout, and migration velocity analysis on synthetic and real data show the presence of clear sub-vertical upper crustal structures near the South Portuguese Zone-Ossa-Morena Zone suture, the Aroche fault. This sub-vertical reflectivity that was not imaged earlier, projects into a location in the lower crust with low reflectivity.

  14. Oblique collision and accretion of the Netherlands Leeward Antilles island arc: A structural analysis of the Caribbean-South American plate boundary zone

    NASA Astrophysics Data System (ADS)

    Beardsley, Amanda Gail

    2007-12-01

    The Netherlands Leeward Antilles volcanic island arc is an ideal natural laboratory to study the evolution of the Caribbean-South American plate boundary. The Leeward Antilles islands (Aruba, Curacao, and Bonaire) are located offshore western Venezuela, within the obliquely convergent diffuse plate boundary zone. Outcrop analysis, microthermometry, and 2D marine seismic reflection data provide evidence of three generations of regional deformation since the Late Cretaceous. Outcrop analysis of structural features, including faults, joints, and veins, characterizes the kinematic history of the islands. Fluid inclusion analysis of quartz and calcite veins coupled with apatite fission-track dating provides the island exhumation history. Finally, marine reflection seismic data processing and interpretation of newly acquired data elucidates offshore structures to integrate with our onshore results. The oldest regional deformation, resulting in both ductile (D1) and brittle (F 1) structures, is attributed to displacement partitioning along the arcuate Caribbean plate boundary. Associated crustal thinning initiated island exhumation, at a rate of 0.18 km/my, from a maximum burial depth of 6 km in the Late Cretaceous (˜89 Ma). Coeval with D1/F1 deformation and exhumation, stretching of the island arc resulted in extensive basin rifting that separated the island blocks. At ˜55 Ma, a change in the relative motion of the Caribbean plate altered plate boundary dynamics. Displacement along the right-lateral Caribbean transform fault and Oca - San Sebastian - El Pilar strike-slip fault system created a wrench tectonic regime within the diffuse plate boundary zone. A second generation of brittle structures (F2) developed while the islands were at a maximum burial depth of 2 km during the Paleocene/Eocene. Since ˜45 Ma, continued motion along the strike-slip fault systems and oblique plate convergence resulted in the youngest generation of structural features (F3). Regional

  15. The formation of precipitate free zones and the growth of grain boundary carbides in the nickel-base superalloy NIMONIC PE16

    SciTech Connect

    Maldonado, R.; Nembach, E.

    1997-01-01

    The formation of precipitate free zones (PFZ) along large and small angle grain boundaries has been investigated for bi- and polycrystals of the nickel-base superalloy NIMONIC PE16. This material is strengthened by coherent precipitates of the {gamma}{prime}-phase. The most important result is that the PFZs are caused by the growth of titanium-rich carbides in the grain boundaries. Since titanium is a constituent of the {gamma}{prime}-precipitates, its depletion along the grain boundaries leads to the dissolution of the {gamma}{prime}-particles and hence to PFZs. The former belief that they are due to chromium-rich grain boundary carbides is disproved. The growth rate of the width W of the PFZs is controlled by the volume diffusion of titanium. Until W reaches its final value W{sub final}, W is proportional to the square root of the aging time. The growth rate of the PFZs yields the volume diffusion coefficient of titanium. The W{sub final} is probably governed by the grain boundaries` limited capacity to accommodate titanium-rich carbides.

  16. Compositional variations in spinel-hosted pargasite inclusions in the olivine-rich rock from the oceanic crust-mantle boundary zone

    NASA Astrophysics Data System (ADS)

    Tamura, Akihiro; Morishita, Tomoaki; Ishimaru, Satoko; Hara, Kaori; Sanfilippo, Alessio; Arai, Shoji

    2016-05-01

    The crust-mantle boundary zone of the oceanic lithosphere is composed mainly of olivine-rich rocks represented by dunite and troctolite. However, we still do not fully understand the global variations in the boundary zone, and an effective classification of the boundary rocks, in terms of their petrographical features and origin, is an essential step in achieving such an understanding. In this paper, to highlight variations in olivine-rich rocks from the crust-mantle boundary, we describe the compositional variations in spinel-hosted hydrous silicate mineral inclusions in rock samples from the ocean floor near a mid-ocean ridge and trench. Pargasite is the dominant mineral among the inclusions, and all of them are exceptionally rich in incompatible elements. The host spinel grains are considered to be products of melt-peridotite reactions, because their origin cannot be ascribed to simple fractional crystallization of a melt. Trace-element compositions of pargasite inclusions are characteristically different between olivine-rich rock samples, in terms of the degree of Eu and Zr anomalies in the trace-element pattern. When considering the nature of the reaction that produced the inclusion-hosting spinel, the compositional differences between samples were found to reflect a diversity in the origin of the olivine-rich rocks, as for example in whether or not a reaction was accompanied by the fractional crystallization of plagioclase. The differences also reflect the fact that the melt flow system (porous or focused flow) controlled the melt/rock ratios during reaction. The pargasite inclusions provide useful data for constraining the history and origin of the olivine-rich rocks and therefore assist in our understanding of the crust-mantle boundary of the oceanic lithosphere.

  17. Relationship of quartz LPO fabrics in mylonites near the Alpine Fault, New Zealand to the attitude of the shear zone boundary

    NASA Astrophysics Data System (ADS)

    Little, T. A.; Prior, D. J.; Toy, V.

    2015-12-01

    The active Alpine fault self-exhumes its own ductile shear zone roots and has known kinematics. Within ~1 km of the fault, the foliation is subparallel to the shear zone boundary in which it formed at amphibolite-facies conditions. Using EBSD, we analysed quartz Lattice Preferred Orientations (LPOs) of mylonites along a central part of the fault. The samples were mostly taken from naturally outcropping rocks, complemented by a few sections from core from the DFDP-2B hole—rocks that accommodated a range of finite strains and that have diverse quartz contents. All the LPOs feature a single (or strongest) girdle of c-axes hat is inclined ~28 ±4° away from the pole to the shear zone boundary (SZB) in a sense that is synthetic to the bulk shear. A point maximum of a-axes is inclined at the same angle relative to the shearing direction. This girdle is perpendicular to C' extensional shear bands in the rock, not to the bulk shear zone boundary, whereas the maximum is parallel to the slip direction of the shear bands. These relationships prevail across large variations in quartz content and finite shear strain magnitude. We infer that quartz LPOs are not always reliable indicators of SZB attitude, and they do not necessarily undergo an obvious rotation relative to the SZB as a function of increasing finite strain. Both the C' shears and the LPOs formed as late-incremental features at orientations controlled by the instantaneous geometry of a non-simple shear flow. We suggest that that the C' planes were aligned to planes of maximum shear-strain-rate. The data can be explained by flow in a thinning and stretching shear zone that deforms in plane strain at a Wk of ~0.7 to ~0.85. In support of this, inversions of seismic focal mechanism data yield an orientation of σ1 for the brittle crust of the central Southern Alps "natural laboratory" that approximately coincides with the predicted orientation of the contractional instantaneous stretching axis for the above

  18. Distribution and mechanism of Neogene to present-day vertical axis rotations, Pacific-Australian Plate Boundary Zone, South Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Little, Timothy A.; Roberts, Andrew P.

    1997-01-01

    Remarkably little knowledge exists about mechanisms of vertical axis rotation in continental crust. Steeply dipping basement rocks in South Island, New Zealand, provide an opportunity to map the distribution of rotations across the Pacific-Australian plate boundary zone, and to delineate boundaries of rotated blocks in unusual detail. We synthesize new structural data with new and existing paleomagnetic data, with geodetic data, and with patterns of Neogene-Quaternary faulting in the strike-slip Marlborough fault system. For the past 20 m.y., vertical axis rotations have been hinged about two crustal-scale boundaries near the east coast. The NE hinge accommodated ˜50° of early-middle Miocene clockwise rotation, which caused deformation of the eastern ends of the Alpine-Wairau and Clarence strike-slip faults. The SW hinge has accommodated a further 30°-50° of finite clockwise rotation since ˜4 Ma and deflects active fault traces. The locus of rotation has shifted southwestward astride a subduction margin that is lengthening in that direction. Rotating rocks are pinned to the south against a locked collision zone where the continental Chatham Rise impinges against the margin. Slip on inland strike-slip faults is transformed seaward across a zone of fault termination into rigid body rotation of a large continental block that has been thrust eastward over the downgoing subducted slab of the Pacific plate. The rotation mechanism is a "migrating hinge," which resembles a flexed telephone book. Strike-slip faults are translated through a brecciated hinge region that does not coincide with a fixed material line in the rock.

  19. Hurricane Mountain Formation melange: history of Cambro-Ordovician accretion of the Boundary Mountains terrane within the northern Appalachian orthotectonic zone

    SciTech Connect

    Boone, G.M.; Boudette, E.L.

    1985-01-01

    The Hurricane Mountain Formation (HMF) melange and associated ophiolitic and volcanogenic formations of Cambrian and lowermost Ordovician age bound the SE margin of the Precambrian Y (Helikian) Chain Lakes Massif in western Maine. HMF melange matrix, though weakly metamorphosed, contains a wide variety of exotic greenschist to amphibolite facies blocks as components of its polymictic assemblage, but blocks of high-grade cratonal rocks such as those of Chain Lakes or Grenville affinity are lacking. Formations of melange exposed in structural culminations of Cambrian and Ordovician rocks NE of the HMF in Maine and in the Fournier Group in New Brunswick are lithologically similar and probably tectonically correlative with the HMF; taken together, they may delineate a common pre-Middle Ordovician tectonic boundary. The authors infer that the Hurricane Mountain and St. Daniel melange belts define the SE and NW margins of the Boundary Mountains accreted terrane (BMT), which may consist of cratonal basement of Chain Lakes affinity extending from eastern Gaspe (deBroucker and St. Julien, 1985) to north-central New Hampshire. The Laurentian continental margin, underlain by Grenville basement, underplated the NW margin of this terrane, marked by the SDF suture zone, in late Cambrian to early Ordovician time, while terranes marked by Cambrian to Tremadocian (.) lithologies dissimilar to the Boundary Mountains terrane were accreted to its outboard margin penecontemporaneously. The docking of the Boundary Mountains terrane and the initiation of its peripheral melanges are equated to the Penobscottian disturbance.

  20. Zoogeography of the San Andreas Fault system: Great Pacific Fracture Zones correspond with spatially concordant phylogeographic boundaries in western North America.

    PubMed

    Gottscho, Andrew D

    2016-02-01

    The purpose of this article is to provide an ultimate tectonic explanation for several well-studied zoogeographic boundaries along the west coast of North America, specifically, along the boundary of the North American and Pacific plates (the San Andreas Fault system). By reviewing 177 references from the plate tectonics and zoogeography literature, I demonstrate that four Great Pacific Fracture Zones (GPFZs) in the Pacific plate correspond with distributional limits and spatially concordant phylogeographic breaks for a wide variety of marine and terrestrial animals, including invertebrates, fish, amphibians, reptiles, birds, and mammals. These boundaries are: (1) Cape Mendocino and the North Coast Divide, (2) Point Conception and the Transverse Ranges, (3) Punta Eugenia and the Vizcaíno Desert, and (4) Cabo Corrientes and the Sierra Transvolcanica. However, discussion of the GPFZs is mostly absent from the zoogeography and phylogeography literature likely due to a disconnect between biologists and geologists. I argue that the four zoogeographic boundaries reviewed here ultimately originated via the same geological process (triple junction evolution). Finally, I suggest how a comparative phylogeographic approach can be used to test the hypothesis presented here. PMID:25521005

  1. Are quartz LPOs predictably oriented with respect to the shear zone boundary?: A test from the Alpine Fault mylonites, New Zealand

    NASA Astrophysics Data System (ADS)

    Little, Timothy A.; Prior, David J.; Toy, Virginia G.

    2016-03-01

    The Alpine fault self-exhumes its own ductile shear zone roots and has a known slip kinematics. Within ˜1 km of the fault, the mylonitic foliation is subparallel to the boundary of the amphibolite-facies ductile shear zone in which it formed. Using EBSD, we analyzed quartz Lattice Preferred Orientations [LPOs) of mylonites along a central part of the Alpine Fault. All LPOs feature a strongest girdle of [c]-axes that is forward-inclined ˜28 ± 4° away from the pole to the fault. A maximum of axes is inclined at the same angle relative the fault. The [c]-axis girdle is perpendicular to extensional (C') shear bands and the maximum is parallel to their slip direction. [c]-axis girdles do not form perpendicular to the SZB. Schmid factor analysis suggests that σ1 was arranged at 60-80° to the Alpine Fault. These observations indicate ductile transpression in the shear zone. The inclined arrangement of [c]-axis girdles, axes, and C' planes relative to the fault can be explained by their alignment relative to planes of maximum shear-strain-rate in a general shear zone, a significant new insight regarding shear zones and how LPO fabrics may generally develop within them. For the Alpine mylonite zone, our data imply a kinematic vorticity number (Wk) of ˜0.7 to ˜0.85. Inversions of seismic focal mechanisms in the brittle crust of the Southern Alps indicate that σ1 is oriented ˜60° to the Alpine Fault; that shear bands form at ˜30° to this direction, and that σ2 and σ3 flip positions between the brittle and ductile parts of the crust.

  2. Conservation Beyond Park Boundaries: The Impact of Buffer Zones on Deforestation and Mining Concessions in the Peruvian Amazon.

    PubMed

    Weisse, Mikaela J; Naughton-Treves, Lisa C

    2016-08-01

    Many researchers have tested whether protected areas save tropical forest, but generally focus on parks and reserves, management units that have internationally recognized standing and clear objectives. Buffer zones have received considerably less attention because of their ambiguous rules and often informal status. Although buffer zones are frequently dismissed as ineffective, they warrant attention given the need for landscape-level approaches to conservation and their prevalence around the world-in Peru, buffer zones cover >10 % of the country. This study examines the effectiveness of buffer zones in the Peruvian Amazon to (a) prevent deforestation and (b) limit the extent of mining concessions. We employ covariate matching to determine the impact of 13 buffer zones on deforestation and mining concessions from 2007 to 2012. Despite variation between sites, these 13 buffer zones have prevented ~320 km(2) of forest loss within their borders during the study period and ~1739 km(2) of mining concessions, an outcome associated with the special approval process for granting formal concessions in these areas. However, a closer look at the buffer zone around the Tambopata National Reserve reveals the difficulties of controlling illegal and informal activities. According to interviews with NGO employees, government officials, and community leaders, enforcement of conservation is limited by uncertain institutional responsibilities, inadequate budgets, and corruption, although formal and community-based efforts to block illicit mining are on the rise. Landscape-level conservation not only requires clear legal protocol for addressing large-scale, formal extractive activities, but there must also be strategies and coordination to combat illegal activities. PMID:27179802

  3. Conservation Beyond Park Boundaries: The Impact of Buffer Zones on Deforestation and Mining Concessions in the Peruvian Amazon

    NASA Astrophysics Data System (ADS)

    Weisse, Mikaela J.; Naughton-Treves, Lisa C.

    2016-08-01

    Many researchers have tested whether protected areas save tropical forest, but generally focus on parks and reserves, management units that have internationally recognized standing and clear objectives. Buffer zones have received considerably less attention because of their ambiguous rules and often informal status. Although buffer zones are frequently dismissed as ineffective, they warrant attention given the need for landscape-level approaches to conservation and their prevalence around the world—in Peru, buffer zones cover >10 % of the country. This study examines the effectiveness of buffer zones in the Peruvian Amazon to (a) prevent deforestation and (b) limit the extent of mining concessions. We employ covariate matching to determine the impact of 13 buffer zones on deforestation and mining concessions from 2007 to 2012. Despite variation between sites, these 13 buffer zones have prevented ~320 km2 of forest loss within their borders during the study period and ~1739 km2 of mining concessions, an outcome associated with the special approval process for granting formal concessions in these areas. However, a closer look at the buffer zone around the Tambopata National Reserve reveals the difficulties of controlling illegal and informal activities. According to interviews with NGO employees, government officials, and community leaders, enforcement of conservation is limited by uncertain institutional responsibilities, inadequate budgets, and corruption, although formal and community-based efforts to block illicit mining are on the rise. Landscape-level conservation not only requires clear legal protocol for addressing large-scale, formal extractive activities, but there must also be strategies and coordination to combat illegal activities.

  4. Crustal Structure of the Caribbean-South American Diffuse Plate Boundary: Subduction Zone Migration and Polarity Reversal Along BOLIVAR Profile 64W

    NASA Astrophysics Data System (ADS)

    Clark, S. A.; Levander, A.; Magnani, M.; Zelt, C. A.; Sawyer, D. S.; Ave Lallemant, H. G.

    2005-12-01

    The BOLIVAR (Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region) project is an NSF funded, collaborative seismic experiment in the southeast Caribbean region. The purpose of the project is to understand the diffuse plate boundary created by the oblique collision between the Caribbean and South American plates. Profile 64W of the BOLIVAR experiment, a 450 km-long, N-S transect onshore and offshore Venezuela located at ~64°W longitude, images the deep crustal structures formed by this collision. The active source components of profile 64W include 300 km of MCS reflection data, 33 coincident OBSs, and 344 land seismic stations which recorded 7500 offshore airgun shots and 2 explosive land shots. Results from the reflection and refraction seismic data along 64W show complex crustal structure across the entire span of the diffuse plate boundary. The onshore portion of 64W crosses the fold and thrust belt of the Serrania del Interior, which formed at ~16 Ma by collision of the Caribbean forearc with the northern South American passive margin. Underlying the Serrania del Interior is a south-vergent, remnant Lesser Antillean subduction zone. As this Lesser Antilles subduction impinged on continental crust, it caused a polarity reversal and jump offshore to the north. Convergence was initially localized in the closure and inversion of the Grenada Basin. However, subduction could not develop because of the ~20-km-thick crust of the Aves Ridge; instead, north-vergent subduction initiated further to the north, where ~12-km-thick Caribbean oceanic crust of the Venezuela Basin began to subduct beneath the Aves Ridge in the Pliocene (~4 Ma) and appears to continue subducting today. Between the remnant subduction zone and the modern one, the El Pilar and Coche dextral strike-slip faults accommodate most of the transform motion of the plate boundary. From the Serrania del Interior to the Aves Ridge, ~260 km of accreted orogenic float comprises the diffuse

  5. Neotectonics of the Owen Fracture Zone (NW Indian Ocean): Structural evolution of an oceanic strike-slip plate boundary

    NASA Astrophysics Data System (ADS)

    Rodriguez, M.; Fournier, M.; Chamot-Rooke, N.; Huchon, P.; Bourget, J.; Sorbier, M.; Zaragosi, S.; Rabaute, A.

    2011-12-01

    The Owen Fracture Zone is a 800 km-long fault system that accommodates the dextral strike-slip motion between India and Arabia plates. Because of slow pelagic sedimentation rates that preserve the seafloor expression of the fault since the Early Pliocene, the fault is clearly observed on bathymetric data. It is made up of a series of fault segments separated by releasing and restraining bends, including a major pull-apart basin at latitude 20°N. Some distal turbiditic channels from the Indus deep-sea fan overlap the fault system and are disturbed by its activity, thus providing landmarks to date successive stages of fault activity and structural evolution of the Owen Fracture Zone from Pliocene to Present. We determine the durability of relay structures and the timing of their evolution along the principal displacement zone, from their inception to their extinction. We observe subsidence migration in the 20°N basin, and alternate activation of fault splays in the vicinity of the Qalhat seamount. The present-day Owen Fracture Zone is the latest stage of structural evolution of the 20-Myr-old strike-slip fault system buried under Indus turbiditic deposits whose activity started at the eastern foot of the Owen Ridge when the Gulf of Aden opened. The evolution of the Owen Fracture Zone since 3-6 Myr reflects a steady state plate motion between Arabia and India, such as inferred by kinematics for the last 20 Myr period. The structural evolution of the Owen Fracture Zone since 20 Myr, including fault segments propagation and migration, pull-apart basin opening and extinction, seems to be characterized by a progressive reorganization of the fault system, and does not require any major kinematics change.

  6. Collaborative Learning in a Boundary Zone: A Case Study of Innovative Inter-Institutional Collaboration in Israel

    ERIC Educational Resources Information Center

    Tabak, Edith; Margolin, Ilana

    2013-01-01

    This qualitative study focused on the collaboration between a school district and a college of education in Israel and aimed to explore how the participants created common understanding in order to promote educational change. The theoretical approach involved analyzing the institutional interconnections based on boundary practices and boundary…

  7. The link between strength of lattice preferred orientation, second phase content and grain boundary migration: A case study from the Alpine Fault zone, New Zealand

    NASA Astrophysics Data System (ADS)

    Little, Timothy A.; Prior, David J.; Toy, Virginia G.; Lindroos, Zoe Reid

    2015-12-01

    We analyse the microstructure and quartz LPOs of 36 layers of varying composition from a several-meter thick sequence of amphibolite-facies metacherts and related mica-garnet-plagioclase-quartz bearing schists from the central Southern Alps in the mylonite zone related to the Alpine Fault. Quartz contents vary from ∼10 to 100% and all of the LPO fabric skeletons are similar, featuring an asymmetric single girdle of [c]-axes inclined ∼30° away from the ZY plane. LPO strength is typically low at quartz contents <70% (M Index of ∼0.05) whereas it may be very high for nearly pure quartz rocks (M Index of up to 4.0). We attribute this change to a sparseness of interphase boundaries in the more quartzose rocks, a reduction in grain-boundary pinning, and a corresponding efficiency of grain boundary migration during dynamic recrystallization. The transition corresponds to a Zener parameter of approximately 700. In layers poor in quartz and rich in mica, the quartz grain size was kept small, and phase-boundary density, high. This may have promoted grain-size sensitive creep and dislocation glide in mica. Dislocation creep in the interspersed quartz grains was correspondingly reduced, and weaker quartz LPOs were produced. In highly quartzose layers, quartz grain boundaries experienced little drag or pinning from impurity phases and were able to migrate quickly into higher strain-energy grains. Preferential consumption of poorly oriented grains strengthened quartz LPOs, geometrically softened the dislocation creep process in these quartzose layers, and contributed to grain coarsening. The lack of evidence for instabilities in the thinly layered (<1 mm, quartz-rich vs. mica-rich) mylonite implies that a combination of deformation mechanisms, grain-size sensitive flow and dislocation creep, in the layers were able to accommodate a nearly homogeneous deformation between the different composition layers.

  8. Transient Deformation at the Seismic-Aseismic Transition in a Mature Plate Boundary Fault Zone - New Zealand's Alpine Fault

    NASA Astrophysics Data System (ADS)

    Toy, V. G.; Norris, R. J.; Prior, D. J.

    2008-12-01

    During the seismic cycle, stresses and strain rates fluctuate in the viscously-deforming zones down-dip of large faults. These transient events produce geological records that can be preserved in exhumed fault zones that have experienced single ruptures (e.g. Sesia Zone, European Western Alps). On the other hand, in major faults that have not experienced a simple, single rupture history, coseismic structures are likely to be destroyed during subsequent cycles of postseismic creep. New Zealand's active Alpine Fault has likely experienced upwards of 20,000 Mw~8 earthquakes, on average one every 200-300 years, over the last ≥5 million years of dextral-reverse slip. Fault rocks generated during these events are exhumed in the hangingwall, exposing materials deformed throughout the seismogenic zone at the surface. We have recognised a structural record of transient events in these rocks that differs from that previously reported elsewhere. Mylonites were formed by viscous shearing of a metasedimentary protolith downdip of the seismogenic structure. Rheological models predict these mylonites should have passed through a crustal strength peak (τ ≥100 MPa) around the brittle-viscous transition. Immediately prior to passing through this transition, they should have developed a small recrystallised grainsize (~10-15μm) and a crystallographic preferred orientation (CPO) indicating slip on the basal system during quartz dislocation creep, as well as a retrograde greenschist-facies mineralogy. However, the high-strain mylonites preserve a large recrystallised grainsize (>~30μm), amphibolite-facies mineralogy and CPO characteristic of prism slip. This suggests they were not significantly deformed at temperatures below ~450°C, significantly above the lower temperature limit for quartz crystal-plasticity at steady-state strain rates in the fault zone Microstructural observations and textural data indicate variable deformation style through the seismic cycle. Large fault

  9. A synthesis and review of geomorphic surfaces of the boundary zone Mt. Taylor to Lucero uplift area, West-Central New Mexico

    SciTech Connect

    Wells, S.G.

    1989-01-01

    The Mt. Taylor volcanic field and Lucero uplift of west-central New Mexico occur in a transitional-boundary zone between the tectonically active Basin-and Range province (Rio Grande rift) and the less tectonically active Colorado plateau. The general geomorphology and Cenozoic erosional history has been discussed primarily in terms of a qualitative, descriptive context and without the knowledge of lithospheric processes. The first discussion of geomorphic surfaces suggested that the erosional surface underlying the Mt. Taylor volcanic rocks is correlative with the Ortiz surface of the Rio Grande rift. In 1978 a study supported this hypothesis with K-Ar dates on volcanic rocks within each physiographic province. The correlation of this surface was a first step In the regional analysis of the boundary zone; however, little work has been done to verify this correlation with numerical age dates and quantitatively reconstruct the surface for neotectonic purposes. Those geomorphic surfaces inset below and younger than the ``Ortiz`` surface have been studied. This report provides a summary of this data as well as unpublished data and a conceptual framework for future studies related to the LANL ISR project.

  10. Modeled temperatures and fluid source distributions for the Mexican subduction zone: Effects of hydrothermal circulation and implications for plate boundary seismic processes

    NASA Astrophysics Data System (ADS)

    Perry, Matthew; Spinelli, Glenn A.; Wada, Ikuko; He, Jiangheng

    2016-02-01

    In subduction zones, spatial variations in pore fluid pressure are hypothesized to control the sliding behavior of the plate boundary fault. The pressure-temperature paths for subducting material control the distributions of dehydration reactions, a primary control on the pore fluid pressure distribution. Thus, constraining subduction zone temperatures are required to understand the seismic processes along the plate interface. We present thermal models for three margin-perpendicular transects in the Mexican subduction zone. We examine the potential thermal effects of vigorous fluid circulation in a high-permeability aquifer within the basaltic basement of the oceanic crust and compare the results with models that invoke extremely high pore fluid pressures to reduce frictional heating along the megathrust. We combine thermal model results with petrological models to determine the spatial distribution of fluid release from the subducting slab and compare dewatering locations with the locations of seismicity, nonvolcanic tremor, slow-slip events, and low-frequency earthquakes. Simulations including hydrothermal circulation are most consistent with surface heat flux measurements. Hydrothermal circulation has a maximum cooling effect of 180°C. Hydrothermally cooled crust carries water deeper into the subduction zone; fluid release distributions in these models are most consistent with existing geophysical data. Our models predict focused fluid release, which could generate overpressures, coincident with an observed ultraslow layer (USL) and a region of nonvolcanic tremor. Landward of USLs, a downdip decrease in fluid source magnitude could result in the dissipation in overpressure in the oceanic crust without requiring a downdip increase in fault zone permeability, as posited in previous studies.

  11. Modeled Temperatures and Fluid Source Distributions for the Mexico Subduction Zone: Effects of Hydrothermal Cooling and Implications for Plate Boundary Seismic Processes

    NASA Astrophysics Data System (ADS)

    Perry, M. R.; Spinelli, G. A.; Wada, I.

    2014-12-01

    In subduction zones, spatial variations in pore fluid pressure are hypothesized to control the distribution and nature of slip behavior (e.g., "normal" earthquakes, slow slip events, non-volcanic tremor, very low frequency earthquakes) on the plate boundary fault. A primary control on the pore fluid pressure distribution in subduction zones is the distribution of fluid release from hydrous minerals in the subducting sediment and rock. The distributions of these diagenetic and metamorphic fluid sources are controlled by the pressure-temperature paths that the subducting material follows. Thus, constraining subduction zone thermal structure is required to inform conceptual models of seismic behavior. Here, we present results of thermal models for the Mexico subduction zone, a system that has received recent attention due to observations of slow-slip events and non-volcanic tremor. We model temperatures in five margin-perpendicular transects from 96 ˚W to 104 ˚W. In each transect, we examine the potential thermal effects of vigorous fluid circulation in a high permeability aquifer within the basaltic basement of the oceanic crust. In the transect at 100˚W, hydrothermal circulation cools the subducting material by up to 140 ˚C, shifting peak slab dehydration landward by ~100 km relative to previous estimates from models that do not include the effects of fluid circulation. The age of the subducting plate in the trench increases from ~3 Ma at 104 ˚W to ~18 Ma at 96 ˚W; hydrothermal circulation redistributes the most heat (and cools the system the most) where the subducting plate is youngest. For systems with <20 Ma subducting lithosphere, hydrothermal circulation in oceanic crust should be considered in estimating subduction zone temperatures and fluid source distributions.

  12. Aeromagnetic evidence for a major strike-slip fault zone along the boundary between the Weddell Sea Rift and East Antarctica

    NASA Astrophysics Data System (ADS)

    Jordan, T. A.; Ferraccioli, F.; Ross, N.; Siegert, M. J.; Corr, H.; Leat, P. T.; Bingham, R. G.; Rippin, D. M.; le Brocq, A.

    2012-04-01

    The >500 km wide Weddell Sea Rift was a major focus for Jurassic extension and magmatism during the early stages of Gondwana break-up, and underlies the Weddell Sea Embayment, which separates East Antarctica from a collage of crustal blocks in West Antarctica. Here we present new aeromagnetic data combined with airborne radar and gravity data collected during the 2010-11 field season over the Institute and Moeller ice stream in West Antarctica. Our interpretations identify the major tectonic boundaries between the Weddell Sea Rift, the Ellsworth-Whitmore Mountains block and East Antarctica. Digitally enhanced aeromagnetic data and gravity anomalies indicate the extent of Proterozoic basement, Middle Cambrian rift-related volcanic rocks, Jurassic granites, and post Jurassic sedimentary infill. Two new joint magnetic and gravity models were constructed, constrained by 2D and 3D magnetic depth-to-source estimates to assess the extent of Proterozoic basement and the thickness of major Jurassic intrusions and post-Jurassic sedimentary infill. The Jurassic granites are modelled as 5-8 km thick and emplaced at the transition between the thicker crust of the Ellsworth-Whitmore Mountains block and the thinner crust of the Weddell Sea Rift, and within the Pagano Fault Zone, a newly identified ~75 km wide left-lateral strike-slip fault system that we interpret as a major tectonic boundary between East and West Antarctica. We also suggest a possible analogy between the Pagano Fault Zone and the Dead Sea transform. In this scenario the Jurassic Pagano Fault Zone is the kinematic link between extension in the Weddell Sea Rift and convergence across the Pacific margin of West Antarctica, as the Dead Sea transform links Red Sea extension to compression within the Zagros Mountains.

  13. Structure and composition of the plate-boundary slip zone for the 2011 Tohoku-Oki earthquake.

    PubMed

    Chester, Frederick M; Rowe, Christie; Ujiie, Kohtaro; Kirkpatrick, James; Regalla, Christine; Remitti, Francesca; Moore, J Casey; Toy, Virginia; Wolfson-Schwehr, Monica; Bose, Santanu; Kameda, Jun; Mori, James J; Brodsky, Emily E; Eguchi, Nobuhisa; Toczko, Sean

    2013-12-01

    The mechanics of great subduction earthquakes are influenced by the frictional properties, structure, and composition of the plate-boundary fault. We present observations of the structure and composition of the shallow source fault of the 2011 Tohoku-Oki earthquake and tsunami from boreholes drilled by the Integrated Ocean Drilling Program Expedition 343 and 343T. Logging-while-drilling and core-sample observations show a single major plate-boundary fault accommodated the large slip of the Tohoku-Oki earthquake rupture, as well as nearly all the cumulative interplate motion at the drill site. The localization of deformation onto a limited thickness (less than 5 meters) of pelagic clay is the defining characteristic of the shallow earthquake fault, suggesting that the pelagic clay may be a regionally important control on tsunamigenic earthquakes. PMID:24311682

  14. Joint Travel-time Inversion of Streamer and OBS Seismic Data for Improved Velocity Models and Interplate Boundary Geometry in Subduction Zone

    NASA Astrophysics Data System (ADS)

    Begovic, S.; Ranero, C. R.; Sallares, V.; Melendez, A.; Grevemeyer, I.

    2015-12-01

    We combine wide-angle (WAS) seismic and multichannel seismic reflection (MCS) data acquired in the northern Chile subduction zone during the CINCA'95 survey into a common inversion scheme to obtain high-resolution image of upper plate and inter-plate boundary, and to characterize seismic velocity (Vp) as well as tectonic structure across ~300 km long, E-W profile, 21.30°S. To illustrate the advantages of a common inversion approach we have compared the modeling results using two different travel-time inversion strategies: First, we have produced seismic velocity and inter-plate boundary geometry using the WAS data, recorded on 19 OBH (Ocean Bottom Hydrophones) and 6 land stations following a typical joint refraction and reflection travel-time tomography strategy. In particular, the WAS model is obtained using tomo2d tomographic inversion code (Korenaga et al, 2000) and applying layer-stripping method. Second, to compare structure, physical properties and rupture characteristics we jointly invert two types of seismic data sets, integrating multichannel seismic (MCS) data collected with a 3 km long streamer with the OBS wide-angle seismic (WAS) data described above into a common inversion scheme. To do so, we have adapted tomo2d to deal with streamer data. The scheme results in a joint travel time tomographic inversion based on integrated travel time information from refracted and reflected from WAS data and reflected phases from the top of the basement and the inter-plate boundaries identified in the MCS shot gathers. Our first results of the joint inversion indicate a 5 - 10 times smaller ray travel-time misfit in the deeper parts of the model around the interplate boundary, compared to models obtained inverting with just wide-angle seismic data. Interpretation of the joint WAS-MCS velocity model, and MCS images provide improved models of physical properties of the upper plate and around inter-plate boundary. In turn this will help to better understand

  15. Refined Views of Strike-slip Fault Zones, Seismicity, and State of Stress Associated With the Pacific-North America Plate Boundary in Southern California

    NASA Astrophysics Data System (ADS)

    Hauksson, E.; Nicholson, C.; Shaw, J. H.; Plesch, A.; Shearer, P. M.; Sandwell, D. T.; Yang, W.

    2013-12-01

    The mostly strike-slip plate boundary in southern California is expressed as a system of late Quaternary faults or principal slip zones (PSZs), with numerous adjacent smaller slip surfaces. It is complex, even after large cumulative displacements, and consists of major fault systems with multi-stranded, non-planar fault geometry, including some in close proximity to each other. There are also secondary cross faults and low-angle detachments that interact with the PSZs accommodating main plate boundary motion. The loading of plate-tectonic strain causes the largest earthquakes along PSZs, moderate-sized events in their immediate vicinity, and small earthquakes across the whole region. We apply relocated earthquake and refined focal mechanism (1981-2013) catalogs, as well as other geophysical datasets to provide refined views of the 3D fault geometry of these active fault systems. To determine properties of individual fault zones, we measure the Euclidian distance from every hypocenter to the nearest PSZ. In addition, we assign crustal geophysical parameters such as heat flow value and shear or dilatation strain rates to each epicenter. We investigate seismogenic thickness and fault zone width as well as earthquake source processes. We find that the seismicity rate is a function of location, with the rate dying off exponentially with distance from the PSZ. About 80% of small earthquakes are located within 5 km of a PSZ. For small earthquakes, stress drops increase in size with distance away from the PSZs. The magnitude distribution near the PSZs suggests that large earthquakes are more common close to PSZs, and they are more likely to occur at greater depth than small earthquakes. In contrast, small quakes can occur at any geographical location. An optimal combination of heat flow and strain rate is required to concentrate the strain along rheologically weak fault zones, which accommodate the crustal deformation processes, causing seismicity. The regional trend of

  16. The lateral boundary of a metamorphic core complex: The Moutsounas shear zone on Naxos, Cyclades, Greece☆

    PubMed Central

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai

    2013-01-01

    We describe the structure, microstructures, texture and paleopiezometry of quartz-rich phyllites and marbles along N-trending Moutsounas shear zone at the eastern margin of the Naxos metamorphic core complex (MCC). Fabrics consistently indicate a top-to-the-NNE non-coaxial shear and formed during the main stage of updoming and exhumation between ca. 14 and 11 Ma of the Naxos MCC. The main stage of exhumation postdates the deposition of overlying Miocene sedimentary successions and predates the overlying Upper Miocene/Pliocene conglomerates. Detailed microstructural and textural analysis reveals that the movement along the Moutsounas shear zone is associated with a retrograde greenschist to subgreenschist facies overprint of the early higher-temperature rocks. Paleopiezometry on recrystallized quartz and calcite yields differential stresses of 20–77 MPa and a strain rate of 10−15–10−13 s−1 at 350 °C for quartz and ca. 300 °C for calcite. Chlorite geothermometry of the shear zone yields two temperature regimes, 300–360 °C, and 200–250 °C. The lower temperature group is interpreted to result from late-stage hydrothermal overprint. PMID:26523079

  17. Step width, spacing, and resolution in gradient elution moving boundary electrophoresis. Part 1. Theory and comparison with zone electrophoresis.

    PubMed

    Ross, David

    2010-11-01

    Gradient elution moving boundary electrophoresis (GEMBE) is a recently described technique for electrophoretic separations in short capillaries or microchannels. With GEMBE, the electrophoretic migration of analytes is opposed by a bulk counterflow of separation buffer. The counterflow velocity is varied over the course of a separation so that analytes with different mobilities enter the separation channel at different times and are detected as moving boundary, step-wise increases in the detector response. The resolution of a GEMBE separation is thus dependent on the rate at which the counterflow velocity is varied, and relatively high-resolution separations can be performed with short microfluidic channels or capillaries. In this paper, a theoretical description of GEMBE is presented that can be used for calculation of expected resolution and for optimization of GEMBE separations. A comparison is made with CZE, a conventional electrophoretic separation technique for which the theoretical understanding is mature. The results indicate that the electric field strength and separation channel length are important parameters for both CZE and GEMBE. However, with GEMBE, the counterflow acceleration is also available as a parameter that can be easily adjusted for optimization of the trade-off between resolution and separation time. This allows for optimization of GEMBE separations by making changes only to the software controlling the apparatus rather than to the hardware of the apparatus itself. Further comparison of the theoretical descriptions of GEMBE and CZE indicates that the time required to achieve a desired resolution is equivalent for the two techniques. PMID:21077236

  18. GPS measurements of crustal deformation within the Pacific-Australia plate boundary zone in Irian Jaya, Indonesia

    NASA Astrophysics Data System (ADS)

    Puntodewo, S. S. O.; McCaffrey, R.; Calais, E.; Bock, Y.; Rais, J.; Subarya, C.; Poewariardi, R.; Stevens, C.; Genrich, J.; Fauzi; Zwick, P.; Wdowinski, S.

    1994-10-01

    Global Positioning System (GPS) measurements made in 1991, 1992 and 1993 provide preliminary estimates of slip distribution between the Australian and Pacific plates in Irian Jaya, Indonesia. We interpret the GPS results with constraints from earthquake mechanisms and slip vectors, recent marine surveys, and geology. Three GPS sites in southeastern Irian Jaya show motions that are within 10 mm/yr of the expected motion of Australia. A coast-to-coast N-S baseline along 140.5°E crosses all known onland regions of active deformation but reveals no more than 15 mm/yr of shortening and 20 mm/yr of left-lateral shear in the 27-month period. The remaining 40 mm/yr of expected convergence between the Pacific and Australian plates probably occurs at the New Guinea trough. GPS sites on the island of Biak, at 136°E, and at Sorong, near the western tip of Bird's Head (at 131°E), both move 90-100 mm/yr in a WSW direction relative to Irian Jaya, but less than 15 mm/yr relative to each other. These sites are on either side of the Sorong fault and demonstrate that it is not presently the major boundary between the Australian and Pacific plates. Instead the plate boundary is now south of the Sorong and Biak sites. Earthquakes suggest possible structures that accomodate motion between Bird's Head and Australia but the relative importance of them remains uncertain.

  19. The Vincent Fault in the San Gabriel Mtns, southern California, USA: a modified plate boundary shear zone

    NASA Astrophysics Data System (ADS)

    Xia, Haoran; Platt, John

    2015-04-01

    The Vincent Fault in southern California separates the ocean-affiliated Pelona schist of Late Cretaceous age in the footwall from a Meso-Proterozoic gneiss complex and Mesozoic granitoid rocks in the hanging wall. The Vincent fault has been regarded as the original megathrust formed during Laramide flat-slab subduction. Our new pressure, temperature and geochronologic data from the rocks in the hanging wall and the footwall indicate that the Vincent fault has undergone post-subduction modification. The Pelona schist in the San Gabriel Mtns was metamorphosed up to high-pressure greenschist facies. The peak metamorphic temperature given by laser Raman spectroscopy of carbonaceous material is 518.9 ± 19.6°C, consistent with the temperature range of 515-550°C from the quartz c-axis opening-angle thermometer. The peak pressure yielded by Si-in-muscovite barometry is 10.5 ± 1 kbar. The upper ~50 m of the Pelona schist was then mylonitized together with the lower 500-800 m of the hanging wall, which overprinted the pre-existing texture. Mylonitization produced a strong ESE-trending lineation in both rock units, with a consistent ESE sense of shear: opposite to what would be predicted by E-directed subduction. Pressure and temperature of mylonitization of the Pelona schist and the lower part of the hangingwall mylonite zone constrained by the Ti-in-quartz thermobarometer and Si-in-muscovite barometer is around ~4.7 kbar and 372 to 425°C; whereas the upper part of the mylonite zone was equilibrated at ~2.4 kbar and ~365°C. The quartz c-axis fabric opening-angle thermometer also gives a temperature range from 360 to 420°C in the entire mylonite zone. Mylonitization therefore took place during exhumation and cooling of the Pelona Schist. Fission track ages of detrital zircons from both the footwall and the hanging wall of the Vincent fault cluster around 46.7 ± 5.9 Ma, indicating that both footwall and hanging wall had cooled to ~200°C by that time. No other major

  20. Repair boundary for parent tube indications within the upper joint zone of hybrid expansion joint (HEJ) sleeved tubes

    SciTech Connect

    Cullen, W.K.; Keating, R.F.

    1997-02-01

    In the Spring and Fall of 1994, and the Spring of 1995, crack-like indications were found in the upper hybrid expansion joint (HEJ) region of Steam Generator (S/G) tubes which had been sleeved using Westinghouse HEJ sleeves. As a result of these findings, analytic and test evaluations were performed to assess the effect of the degradation on the structural, and leakage, integrity of the sleeve/tube joint relative to the requirements of the United States Nuclear Regulatory Commission`s (NRC) draft Regulatory Guide (RG) 1.121. The results of these evaluations demonstrated that tubes with implied or known crack-like circumferential parent tube indications (PTIs) located 1.1 inches or farther below the bottom of the hardroll upper transition, have sufficient, and significant, integrity relative to the requirements of RG 1.121. Thus, the purpose of this report is to provide background information related to the justification of the modified tube repair boundary.

  1. Geophysical and Chemical Weathering Signatures Across the Deep Weathered-Unweathered Granite Boundary of the Calhoun Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Richter, D., Jr.; Bacon, A. R.; Brantley, S. L.; Holbrook, W. S.

    2015-12-01

    To understand the relationship between geophysical measurements and chemical weathering at Earth's surface, we combine comprehensive chemical and physical analyses of a 70-m granite weathering profile in the Southern Piedmont in the southeastern United States. The research site is in the uplands of the Calhoun Critical Zone Observatory and is similar to many geomorphically stable, ancient, and highly-weathered Ultisol soils of the region. Surface and downhole geophysical analyses suggest significant physical changes to depths of about 40 m, where geophysical properties are consistent with competent and unweathered granite. At this depth, surface refraction velocities increase to >4.5 km/s; variations in downhole sonic velocities decrease by more than two-fold; and deviations in the downhole caliper log sharply decrease as well. Forty meters depth is also the depth of initiation of plagioclase feldspar weathering, as inferred from bulk geochemical measurement of the full 70-m deep core. Specifically, element-depth profiles, cast as mass transfer coefficient profiles using Ti and Zr as immobile elements, document inferred loss of plagioclase in the depth interval between 15 and 40-m depth. Plagioclase feldspar is the most abundant of the highly reactive minerals in the granite. Such a wide reaction front is characteristic of weathering granites. Some loss of K is observed at these depths but most K loss, as well as Mg loss, occurs at shallower depths. Nearby geophysical profiles and 3D stress models have been interpreted as showing that seismic velocities decrease at 40 m depth due to opening of fractures as rock is exhumed toward the surface. Given our interpretations of both the geochemical and geophysical data, we infer that the onset of chemical weathering of feldspar coincides with the opening of these fractures. The data highlight the ability of geochemistry and geophysics to complement each other and enrich our understanding of Earth's Critical Zone.

  2. Partitioning of oblique convergence in the Northern Andes subduction zone: Migration history and the present-day boundary of the North Andean Sliver in Ecuador

    NASA Astrophysics Data System (ADS)

    Alvarado, A.; Audin, L.; Nocquet, J. M.; Jaillard, E.; Mothes, P.; Jarrín, P.; Segovia, M.; Rolandone, F.; Cisneros, D.

    2016-05-01

    Along the Ecuadorian margin, oblique subduction induces deformation of the overriding continental plate. For the last 15 Ma, both exhumation and tectonic history of Ecuador suggest that the northeastward motion of the North Andean Sliver (NAS) was accompanied by an eastward migration of its eastern boundary and successive progressively narrowing restraining bends. Here we present geologic data, earthquake epicenters, focal mechanisms, GPS results, and a revised active fault map consistent with this new kinematic model. All data sets concur to demonstrate that active continental deformation is presently localized along a single major fault system, connecting fault segments from the Gulf of Guayaquil to the eastern Andean Cordillera. Although secondary faults are recognized within the Cordillera, they accommodate a negligible fraction of relative motion compared to the main fault system. The eastern limit is then concentrated rather than distributed as first proposed, marking a sharp boundary between the NAS, the Inca sliver, and the Subandean domain overthrusting the South American craton. The NAS limit follows a northeast striking right-lateral transpressional strike-slip system from the Gulf of Guayaquil (Isla Puná) to the Andean Cordillera and with the north-south striking transpressive faults along the eastern Andes. Eastward migration of the restraining belt since the Pliocene, abandonment of the sutures and reactivation of north-south striking ancient fault zones lead to the final development of a major tectonic boundary south and east of the NAS, favoring its extrusion as a continental sliver, accommodating the oblique convergence of the Nazca oceanic plate toward South America.

  3. Rapid Kinematic and Tectonic Variations Along the 1400-km-long Australia-Woodlark Plate Boundary Zone, Papua New Guinea and Woodlark Basin

    NASA Astrophysics Data System (ADS)

    Mann, P.; Taylor, F. W.; Gahagan, L.; Watson, L.

    2004-12-01

    Previous GPS studies have shown the wide variability in present-day plate motions across the highly arcuate, 1400-km-long Australia-Woodlark plate boundary extending from Papua New Guinea to the Solomon Islands. GPS-determined motions range from orthogonal oceanic spreading in the Woodlark basin, to continental transtension in the 2.5-km-high core complex area of easternmost Papua New Guinea, to continental strike-slip and transpression in 4-km-high mountains of the Papuan Peninsula. We use imagery, earthquake focal mechanisms, coral reef uplift data, and structural mapping studies to establish the along-strike continuity of the active plate boundary fault. Systematic angular changes in the direction of the plate vector along this continuous fault explain its varied tectonic geomorphology, Holocene uplift history, and geologic structure. We use a series of plate reconstructions to illustrate the longer term, Cenozoic evolution of this boundary including: its formation as an arcuate, N- and NE-dipping ophiolitic suture zone during Paleogene time, the progressive "unzippering" of this thrust over the past 6 Ma along a N- and NE-dipping, low-angle normal fault in easternmost Papua New Guinea, and its "zippering" or continued shortening on the suture thrust in the Owen Stanley Ranges of the Papuan Peninsula. Over the 1400-km-length of the fault, the length of segments of oceanic spreading, transtension, and transpression is 250-500 km; the time period separating one tectonic style from the succeeding style encroaching from the east is several million years. This systematic spatial and temporal superposition of tectonic styles, leads to complex - but predictable - along-strike variations in geologic history.

  4. Timing of Deformation in the Central Metasedimentary Belt Boundary Thrust Zone (CMBbtz), southern Ontario, Canada, from Electron Microprobe Dating of Monazite

    NASA Astrophysics Data System (ADS)

    Markley, M. J.; Dunn, S. R.; Peck, W. H.; Jercinovic, M. J.; Williams, M. L.

    2015-12-01

    In the Grenville Province of Southern Ontario, the Central Metasedimentary Belt boundary thrust zone (CMBbtz) is a crustal-scale tectonic boundary between the older, granulite-facies Central Gneiss Belt to the NW and the younger, amphibolite-facies Central Metasedimentary Belt to the SE. Although there are a range of tectonic models for the CMBbtz, most workers agree it is a major tectonic boundary that accommodated ductile thrusting and crustal shortening during the Ottawan phase of the Grenville Orogeny (~1080-1020 Ma). Some studies suggest that ductile thrusting in the CMBbtz was roughly synchronous with synorogenic extensional collapse below an orogenic lid. Previous geochronological studies also provide evidence of earlier deformation and/or metamorphic events in the CMBbtz, although the relation between deformation in the CMBbtz to the Elzeviran (~1230 Ma) and Shawinigan (~1180 Ma) orogenies is unclear. Our study is the first to report in situ electron microprobe monazite (mnz) dates from amphibolite-grade ortho- and para-gneisses of the CMBbtz. Our results are broadly consistent with other chronometers. We present dates from 132 age-domains within 83 mnz grains in 14 samples. Although our data provide strong evidence for deformation and metamorphism along the length of the CMBbtz during the Ottawan (1080-1020 Ma), we also report two other clusters of ages: 1140-1110 Ma and 1230-1170 Ma. The latter cluster falls between the widely accepted ranges for the Elzeviran and Shawinigan orogenies. In addition, some individual outcrops, particularly those in Killaloe and Minden, show mnz ages spanning over 200 m.y., and the setting and compositions of individual monazite domains allow us to link mnz growth to episodes of garnet growth during multiple events. Together these data indicate an unexpectedly continuous and long-lived period of deformation and metamorphism in the CMBbtz.

  5. A model for the termination of the Ryukyu subduction zone against Taiwan: A junction of collision, subduction/separation, and subduction boundaries

    USGS Publications Warehouse

    Wu, F.T.; Liang, W.-T.; Lee, J.-C.; Benz, H.; Villasenor, A.

    2009-01-01

    The NW moving Philippine Sea plate (PSP) collides with the Eurasian plate (EUP) in the vicinity of Taiwan, and at the same time, it subducts toward the north along SW Ryukyu. The Ryukyu subduction zone terminates against eastern Taiwan. While the Ryukyu Trench is a linear bathym??trie low about 100 km east of Taiwan, closer to Taiwan, it cannot be clearly identified bathymetrically owing to the deformation related to the collision, making the location of the intersection of the Ryukyu with Taiwan difficult to decipher. We propose a model for this complex of boundaries on the basis of seismicity and 3-D velocity structures. In this model the intersection is placed at the latitude of about 23.7??N, placing the northern part of the Coastal Range on EUP. As PSP gets deeper along the subduction zone it collides with EUP on the Taiwan side only where they are in direct contact. Thus, the Eurasian plate on the Taiwan side is being pushed and compressed by the NW moving Philippine Sea plate, at increasing depth toward the north. Offshore of northeastern Taiwan the wedge-shaped EUP on top of the Ryukyu subducting plate is connected to the EUP on the Ryukyu side and coupled to the NW moving PSP by friction at the plate interface. The two sides of the EUP above the western end of the subduction zone are not subjected to the same forces, and a difference in motions can be expected. The deformation of Taiwan as revealed by continuous GPS measurements, geodetic movement along the east coast of Taiwan, and the formation of the Hoping Basin can be understood in terms of the proposed model. Copyright 2009 by the American Geophysical Union.

  6. Topography and tectonics of the central New Madrid seismic zone: Results of numerical experiements using a three-dimensional boundary element program

    NASA Technical Reports Server (NTRS)

    Gomberg, Joan; Ellis, Michael

    1994-01-01

    We present results of a series of numerical experiments designed to test hypothetical mechanisms that derive deformation in the New Madrid seismic zone. Experiments are constrained by subtle topography and the distribution of seismicity in the region. We use a new boundary element algorithm that permits calcuation of the three-dimensional deformation field. Surface displacement fields are calculated for the New Madrid zone under both far-field (plate tectonics scale) and locally derived driving strains. Results demonstrate that surface displacement fields cannot distinguish between either a far-field simple or pure shear strain field or one that involves a deep shear zone beneath the upper crustal faults. Thus, neither geomorphic nor geodetic studies alone are expected to reveal the ultimate driving mechanism behind the present-day deformation. We have also tested hypotheses about strain accommodation within the New Madrid contractional step-over by including linking faults, two southwest dipping and one vertical, recently inferred from microearthquake data. Only those models with step-over faults are able to predict the observed topography. Surface displacement fields for long-term, relaxed deformation predict the distribution of uplift and subsidence in the contractional step-over remarkably well. Generation of these displacement fields appear to require slip on both the two northeast trending vertical faults and the two dipping faults in the step-over region, with very minor displacements occurring during the interseismic period when the northeast trending vertical faults are locked. These models suggest that the gently dippling central step-over fault is a reverse fault and that the steeper fault, extending to the southeast of the step-over, acts as a normal fault over the long term.

  7. Breaking into the Plate: Seismic and Hydroacoustic Analysis of a 7.6 Mw Oceanic Fracture Zone Earthquake Adjacent to the Central Indian Ridge Plate Boundary

    NASA Astrophysics Data System (ADS)

    Bohnenstiehl, D. R.; Tolstoy, M.; Chapp, E.

    2003-12-01

    Where oceanic spreading segments are offset laterally from one another, the differential motion of the plates is accommodated by strike-slip motion along ridge-perpendicular transform faults. Off-axis from the ridge-transform intersection, no differential motion is require, and the fracture zone trace is thought to be inactive except where reactivated by intra-plate stresses. On 15 July 2003, an earthquake with a magnitude of 7.6 Mw occurred near the northern Central Indian Ridge (CIR), the divergent boundary separating the Somalian plate from the Indian and Australian plates. The size of this event places it within the 99th quantile of magnitude for shallow (< 40 km depth) strike-slip events (null axis plunge >45 deg) within the global Harvard CMT catalog. The earthquake's epicenter is near 2.5 deg S, 68.33 deg E, where the CIR is marked by a series of short (<100 km long) right-stepping transforms that offset the northwest trending spreading segments (20 mm/yr). Seismic signals associated with the mainshock and its largest aftershocks were recorded well by land-based seismic networks. Regional seismic phases (Pn, Sn), as well oceanic T-waves, where also recorded at an IMS hydroacoustic station to the north of the Diego Garcia atoll. T-wave signals recorded at Diego Garcia were cross correlated to determine accurate travel time differences. These traveltime differences were used in a plane wave fitting inversion to determine the horizontal slowness components and estimate the back azimuth to the epicenter. Aftershock locations are derived using the azimuthal information and Pn-T traveltime differences. Together, the seismically- and hydroacoustically-derived epicenters show a linear band of aftershocks extending more than 200 km along the off-axis trace of a right stepping transform. We interpret these aftershock events as delineating the length of the mainshock rupture. As the well-constrain hypocenter of the mainshock lies near the western edge of this

  8. The distribution of superficial zone protein (SZP)/lubricin/PRG4 and boundary mode frictional properties of the bovine diarthrodial joint.

    PubMed

    Peng, Gordon; McNary, Sean M; Athanasiou, Kyriacos A; Reddi, A Hari

    2015-09-18

    The diarthrodial, knee joint is a remarkably efficient bearing system; articulating cartilage surfaces provide nearly frictionless performance with minimal wear. The low friction properties of the cartilage surfaces are due in part to the boundary lubricant, superficial zone protein (SZP); also known as lubricin or proteoglycan 4 (PRG4). In previous work, SZP localization and cartilage friction were examined across the femoral condyles. Studies in the literature have also individually investigated the other tissues that comprise the human knee and four-legged animal stifle joint, such as the meniscus or patella. However, comparisons between individual studies are limited due to the variable testing conditions employed. Friction is a system property that is dependent on the opposing articulating surface, entraining speed, and loading. A cross-comparison of the frictional properties and SZP localization across the knee/stifle joint tissues utilizing a common testing configuration is therefore needed. The objective of this investigation was to determine the friction coefficient and SZP localization of the tissues comprising the three compartments of the bovine stifle joint: patella, patellofemoral groove, femoral condyles, meniscus, tibial plateau, and anterior cruciate ligament. The boundary mode coefficient of friction was greater in tissues of the patellofemoral compartment than the lateral and medial tibiofemoral compartments. SZP immunolocalization followed this trend with reduced depth of staining and intensity in the patella and patellofemoral groove compared to the femoral condyles and tibial plateau. These results illustrate the important role of SZP in reducing friction in the tissues and compartments of the knee/stifle joint. PMID:26117076

  9. Deep structure of the east Terre Adélie Craton boundary (East Antarctica): Seismic investigation of the Mertz shear zone area.

    NASA Astrophysics Data System (ADS)

    Lamarque, Gaelle; Barruol, Guilhem; Fontaine, Fabrice; Bascou, Jérôme; Cottin, Jean-Yves; Ménot, René-Pierre

    2014-05-01

    The Mertz shear zone (MSZ) located in George Vth Land (67°S, 145°E) is a key area to understand tectonic relationships between the Neoarchean-Paleoproterozoic Terre Adélie Craton (TAC) and the Early Paleozoic units of Cape Webb and Penguin Point. The MSZ is therefore a major structure that represents the eastern boundary of the East Antartica Shield. In addition, the MSZ that recorded dextral strike-slip movement estimated at 1.7Ga could be correlated to the Kalinjila shear zone a large scale mylonitic structure outcropping at the east of the Gawler Craton (South Australia). In order to better understand the MSZ dynamics, we developed a multi-disciplinary approach with the French polar institute (IPEV) through the Arlita program (Architecture de la Lithosphere de Terre Adélie). Four temporary seismic stations were deployed on both sides and above the MSZ from October 2009 to October 2011 to map the deep tectonic structures. We analysed receiver functions to evaluate Moho depth and seismic anisotropy through the splitting of SKS waves to analyze the prolongation of the MSZ structures into the mantle. Results from receiver functions reveal Moho depths of 40-44km for the TAC, about 36 km under the MSZ and 28km for the Paleozoic domain. These results show that the MSZ delimit two crustal blocks with different thicknesses. Our study is consistent with crustal thicknesses estimated by Fontaine et al. (2012) in South Australia in the Gawler craton (>40km) and in the Delamerian orogen terrains (31km). However, the transition between the thick craton and the Paleozoic crust is sharper at the MSZ than in south Australia. Seismic anisotropy in the MSZ area was studied from events of magnitudes ranging from 5.9 to 7.0. In addition, petrological and crystallographic fabrics of the crust were carry out in order to better constrain the observed SKS delay times. The measurements of the splitting parameters show a fast polarisation direction (Φ) parallel to the E-W coast and

  10. The Saint-Georges-sur-Loire olistostrome, a key zone to understand the Gondwana-Armorica boundary in the Variscan belt (Southern Brittany, France)

    NASA Astrophysics Data System (ADS)

    Cartier, Carine; Faure, Michel

    2004-12-01

    In the southern part of the French Armorican massif, the Ligerian domain is located along the boundary between Gondwana and Armorica. Lithological, geochemical and structural data on the Saint-Georges-sur-Loire Unit, which is the northern part of the Ligerian domain, allow us to distinguish two sub-units. A southern sub-unit, formed by various blocks (chert, limestone, sandstone, rhyolite, mafic rocks) of Silurian to Middle Devonian age included as olistoliths in a Middle-Late Devonian terrigeneous matrix, overthrusts a sandstone-pelite northern sub-unit. Both units experienced two deformation events. The first one is a top-to-the-NW thrusting and the second one is a left-lateral wrenching. The Saint-Georges-sur-Loire Unit is an accretionary prism formed during the Late Devonian closure of the Layon rift, coeval with the main phase of the Variscan orogeny. The Layon rift, which according to the mafic olistoliths was partly floored by oceanic crust, appears as a buffer structural zone that accounts for the lack in Central Brittany of any tectonic or sedimentary echo of the closure of the Medio-European Ocean. The tectonic evolution of the Saint-Georges-sur-Loire Unit supports a polyorogenic model for this part of the Variscan Belt.

  11. Lu-Hf garnet geochronology applied to plate boundary zones: Insights from the (U)HP terrane exhumed within the Woodlark Rift

    NASA Astrophysics Data System (ADS)

    Zirakparvar, N. A.; Baldwin, S. L.; Vervoort, J. D.

    2011-09-01

    High-pressure and ultra high-pressure (U)HP metamorphic rocks occur in many of the world's major orogenic belts, suggesting that subduction of continental lithosphere is a geologically important process. Despite the widespread occurrence of these rocks, relatively little is known about the timescales associated with (U)HP metamorphism. This is because most (U)HP terranes are tectonically overprinted and juxtaposed against rocks with a different history. An exception to this are the Late Miocene (U)HP metamorphic rocks found in active metamorphic core complexes (MCC) in the Woodlark Rift of southeastern Papua New Guinea. This region provides a rare opportunity to study the garnet Lu-Hf isotopic record of (U)HP metamorphism in a terrane that is not tectonically overprinted. In order to constrain the timing of garnet growth relative to the history of (U)HP metamorphism and the evolution of the Woodlark Rift, Lu-Hf ages were determined, in conjunction with measurements of Lu and major element zoning, for garnets from three metamorphic rocks. Garnets from the three samples yielded different ages that, instead of recording the spatial and temporal evolution associated with a single metamorphic event, provide information on the timing of three separate plate boundary events. The youngest Lu-Hf age determined was 7.1 ± 0.7 Ma for garnets in a Late Miocene coesite eclogite. The age is interpreted to record the time when a garnet-bearing partial melt of the mantle crystallized within subducted continental lithosphere at (U)HP conditions. The young Lu-Hf age from the coesite eclogite is in contrast to a 68 ± 3.6 Ma Lu-Hf age obtained on large (1-2 cm) garnet porphyroblasts, from within the Pleistocene amphibolite facies shear zone carapace bounding exposures of (U)HP rocks in the D'Entrecasteaux Islands. This older age records the growth of garnet in response to continental subduction and ophiolite obduction in the region north and east of Australia during late Mesozoic

  12. Plate boundary and major fault system in the overriding plate within the Shumagin gap at the Alaska-Aleutian subduction zone

    NASA Astrophysics Data System (ADS)

    Becel, A.; Shillington, D. J.; Nedimovic, M. R.; Keranen, K. M.; Li, J.; Webb, S. C.; Kuehn, H.

    2013-12-01

    Structure in the overriding plate is one of the parameters that may increase the tsunamigenic potential of a subduction zone but also influence the seismogenic behavior and segmentation of great earthquake rupture. The Alaska-Aleutian margin is characterized by along-strike changes in plate interface coupling over relatively small distances. Here, we present trench normal multichannel seismic (MCS) profiles acquired across the Shumagin gap that has not broken in many decades and appears to be weakly coupled. The high fold, deep penetration (636 channel, 8-km long streamer, 6600 cu.in airgun source) MCS data were acquired as part of the ALEUT project. This dataset gives us critical new constraints on the interplate boundary that can be traced over ~100 km distance beneath the forearc with high variation in its reflection response with depth. These profiles also reveal the detailed upper plate fault structure and forearc morphology. Clear reflections in the overriding plate appear to delineate one or more large faults that cross the shelf and the upper slope. These faults are observed 75 km back from the trench and seem to branch at depth and connect to the plate interface within this gap at ~11 s twtt. We compare the reflective structure of these faults to that of the plate boundary and examine where it intersects the megathrust with respect of the expected downdip limit of coupling. We also compare this major structure with the seismicity recorded in this sector. The imaged fault system is associated with a large deep basin (~6s twt) that is an inherited structure formed during the pre-Aleutian period. Basins faults appear to have accommodated primarily normal motion, although folding of sediments near the fault and complicated fault geometries in the shallow section may indicate that this fault has accommodated other types of motion during its history that may reflect the stress-state at the megathrust over time. The deformation within the youngest sediment also

  13. Atrial Fibrillation (AF or AFib)

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Atrial Fibrillation (AF or AFib) Updated:Feb 10,2016 What ... to the Terms and Conditions and Privacy Policy Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  14. Pathogenesis of AF: Impact on intracardiac signals

    PubMed Central

    Shah, Ashok J; Dubois, Rémi; Miyazaki, Shinsuke; Jadidi, Amir S; Scherr, Daniel; Wilton, Stephen B; Roten, Laurent; Pascale, Patrizio; Pedersen, Michala; Derval, Nicolas; Knecht, Sebastien; Sacher, Frederic; Jais, Pierre; Narayan, Sanjiv; Hocini, Mélèze; Haïssaguerre, Michel

    2014-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia, and is responsible for the highest number of rhythm-related disorders and cardioembolic strokes worldwide. Intracardiac signal analysis during the onset of paroxysmal AF led to the discovery of pulmonary vein as a triggering source of AF, which has led to the development of pulmonary vein ablation—an established curative therapy for drug-resistant AF. Complex, multicomponent and rapid electrical activity widely involving the atrial substrate characterizes persistent/permanent AF. Widespread nature of the problem and complexity of signals in persistent AF reduce the success rate of ablation therapy. Although signal processing applied to extraction of relevant features from these complex electrograms has helped to improve the efficacy of ablation therapy in persistent/permanent AF, improved understanding of complex signals should help to identify sources of AF and further increase the success rate of ablation therapy. PMID:22255589

  15. Plume Generation Zones On The Core Mantle Boundary: their origin and what they tell about how the Earth works - and how it has worked (Arthur Holmes Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Burke, Kevin

    2014-05-01

    It is more than 50 years since Wilson (1963) suggested that a fixed plume of deep origin from the convecting mantle is generating the Hotspots of the Hawaiian chain on the overlying moving rigid lithosphere and nearly 45 years since Morgan (1972) followed by suggesting that the plumes which generate Hotspots rise only from the Core/Mantle Boundary (CMB). During the past ~ 15 years testing has begun of a refinement of Morgan's idea based on the observation that Plumes responsible for Hotspots, Large Igneous Provinces (LIPs) and a significant fraction of other igneous rocks (including kimberlites) originate only in Plume Generation Zones (PGZs) at the edges on the CMB of one or other of TUZO and JASON the 2 antipodal, equatorial, Large Low Shear Wave Velocity Provinces (LLSVPs) of the deep mantle (Garnero et al. 2007) or from similar PGZs at the edges on the CMB of ~8 smaller Low Shear Wave Velocity Provinces. Today I will: (i) demonstrate using dated Hotspot, Large Igneous Province and Kimberlite occurrence history and paleomagnetic rotations (e.g. Torsvik et al. 2010, Burke et al.2008) the stability throughout the past 0.55 Ga of the LLSVPs and LSVPs (ii) show from the history of the Earth and Mars how the LLSVPs and LSVPs are likely to have formed early in Earth history and to have been stable since ~ 4.4 Ga (Burke et al. 2012) (iii) show, following an analogy suggested by Jack Whitehead of similarity to atmospheric fronts, why plumes are generated only from PGZs on the CMB at the margins of LLSVPs and LSVPs. (iv) show from results of recent seismological studies of Iceland, Jan Mayen, Hawaii, Yellowstone, the Afar and Ontong Java, that although plumes rise vertically in the deep mantle from the CMB their fate in the top ~ 1, 000 km of the mantle is proving to be varied and to depend largely, as Wilson suggested, on how they interact with the plates above them. Properties of the Plume Generation Zones (PGZs) on the CMB and of the plumes that rise from them are

  16. Characterizing a large shear-zone with seismic and magnetotelluric methods: The case of the Dead Sea Transform

    USGS Publications Warehouse

    Maercklin, N.; Bedrosian, P.A.; Haberland, C.; Ritter, O.; Ryberg, T.; Weber, M.; Weckmann, U.

    2005-01-01

    Seismic tomography, imaging of seismic scatterers, and magnetotelluric soundings reveal a sharp lithologic contrast along a ???10 km long segment of the Arava Fault (AF), a prominent fault of the southern Dead Sea Transform (DST) in the Middle East. Low seismic velocities and resistivities occur on its western side and higher values east of it, and the boundary between the two units coincides partly with a seismic scattering image. At 1-4 km depth the boundary is offset to the east of the AF surface trace, suggesting that at least two fault strands exist, and that slip occurred on multiple strands throughout the margin's history. A westward fault jump, possibly associated with straightening of a fault bend, explains both our observations and the narrow fault zone observed by others. Copyright 2005 by the American Geophysical Union.

  17. Remote life-detection criteria, habitable zone boundaries, and the frequency of Earth-like planets around M and late K stars.

    PubMed

    Kasting, James F; Kopparapu, Ravikumar; Ramirez, Ramses M; Harman, Chester E

    2014-09-01

    The habitable zone (HZ) around a star is typically defined as the region where a rocky planet can maintain liquid water on its surface. That definition is appropriate, because this allows for the possibility that carbon-based, photosynthetic life exists on the planet in sufficient abundance to modify the planet's atmosphere in a way that might be remotely detected. Exactly what conditions are needed, however, to maintain liquid water remains a topic for debate. In the past, modelers have restricted themselves to water-rich planets with CO2 and H2O as the only important greenhouse gases. More recently, some researchers have suggested broadening the definition to include arid, "Dune" planets on the inner edge and planets with captured H2 atmospheres on the outer edge, thereby greatly increasing the HZ width. Such planets could exist, but we demonstrate that an inner edge limit of 0.59 AU or less is physically unrealistic. We further argue that conservative HZ definitions should be used for designing future space-based telescopes, but that optimistic definitions may be useful in interpreting the data from such missions. In terms of effective solar flux, S(eff), the recently recalculated HZ boundaries are: recent Venus--1.78; runaway greenhouse--1.04; moist greenhouse--1.01; maximum greenhouse--0.35; and early Mars--0.32. Based on a combination of different HZ definitions, the frequency of potentially Earth-like planets around late K and M stars observed by Kepler is in the range of 0.4-0.5. PMID:24277805

  18. Remote life-detection criteria, habitable zone boundaries, and the frequency of Earth-like planets around M and late K stars

    PubMed Central

    Kasting, James F.; Kopparapu, Ravikumar; Ramirez, Ramses M.; Harman, Chester E.

    2014-01-01

    The habitable zone (HZ) around a star is typically defined as the region where a rocky planet can maintain liquid water on its surface. That definition is appropriate, because this allows for the possibility that carbon-based, photosynthetic life exists on the planet in sufficient abundance to modify the planet’s atmosphere in a way that might be remotely detected. Exactly what conditions are needed, however, to maintain liquid water remains a topic for debate. In the past, modelers have restricted themselves to water-rich planets with CO2 and H2O as the only important greenhouse gases. More recently, some researchers have suggested broadening the definition to include arid, “Dune” planets on the inner edge and planets with captured H2 atmospheres on the outer edge, thereby greatly increasing the HZ width. Such planets could exist, but we demonstrate that an inner edge limit of 0.59 AU or less is physically unrealistic. We further argue that conservative HZ definitions should be used for designing future space-based telescopes, but that optimistic definitions may be useful in interpreting the data from such missions. In terms of effective solar flux, Seff, the recently recalculated HZ boundaries are: recent Venus—1.78; runaway greenhouse—1.04; moist greenhouse—1.01; maximum greenhouse—0.35; and early Mars—0.32. Based on a combination of different HZ definitions, the frequency of potentially Earth-like planets around late K and M stars observed by Kepler is in the range of 0.4–0.5. PMID:24277805

  19. Revealing the architecture of the upper boundary of the Philippine Sea Plate beneath the northern tip of the Izu-Tanzawa Collision Zone, Central Japan, using later-phase of P waves

    NASA Astrophysics Data System (ADS)

    Shuri, Y.; Tsumura, N.

    2010-12-01

    In Izu-Tanzawa Collision Zone (ITCZ), Izu arc collides with Japan arc due to subduction of the Philippine Sea plate (PHP). Recent studies by Kikuchi (2008) and Arai et al. (2009) have revealed that the upper boundary of PHP has a complex geometry in this area. High seismicity near the top boundary of PHP is reported in the front (northern) edge of the ITCZ, which is the transition zone from collision to subduction of PHP, whereas an aseismic zone is located on the western part of the high seismicity region. This spatial variation of seismicity is probably related to the shape of PHP caused by the difference between collisional vs. subductive movements. To better correlate the spatial distribution of seismicity and the plate configuration, we attempt to find a discontinuous surface near the upper boundary of PHP using later phases of P waves. We used seismic-waveform data from the website of Hi-net seismic network. In the high seismicity region, clear later phases of P waves (X phases) are observed in vertical component seismograms recorded at the stations above the high seismicity region. The X phases arrive 0.5s to 2.0s after P arrivals. Time difference between P and X arrivals (X-P times) increases with distances between the plate boundary and the hypocenters. Similarly, X-P times increase as the distances from the northwestern edge of the high seismicity region to the hypocenters increase. These observations suggest two possibilities for the origin of the X phases: (1) a converted wave at the upper boundary of PHP or (2) a reflected wave from the edge of the high seismicity region. First we searched a suitable plane for which calculated X-P times can match the observed X-P times, by assuming the X phases are converted waves. We found that two converted planes located at different depths would best explain all observed X-P times simultaneously; the depth of the estimated plane in the western side of the high seismicity zone is deeper than that of the eastern side

  20. Crustal movements at a divergent plate boundary: interplay between volcano deformation, geothermal processes, and plate spreading in the Northern Volcanic Zone, Iceland since 2008.

    NASA Astrophysics Data System (ADS)

    Drouin, Vincent; Sigmundsson, Freysteinn; Hreinsdóttir, Sigrún; Ofeigsson, Benedikt G.; Sturkell, Erik; Islam, Tariqul

    2014-05-01

    Iceland is a subaerial part of the Mid-Atlantic Ridge, where the divergent plate boundary between the North-American and Eurasian Plates can be studied. The Northern Volcanic Zone (NVZ) of Iceland, comprised of several volcanic systems, is particularly well suited to study interplay between volcanoes, geothermal areas and plate spreading, as the zone is relatively simple and accommodates the full spreading of the plates (18.6 mm/yr in a direction of 105 degrees according to NUVEL-1A predictions). The most recent volcanic activity in the area was the Krafla rifting episode (1975-1984). In 2007-2008 two intrusive events were detected: one in Upptypingar and the other in Þeistareykir. Extensive crustal deformation studies have been carried out in the NVZ; we report the results of recent GPS and Interferometric Synthetic Aperture Radar (InSAR) studies focusing on Krafla, Þeistareykir and Askja volcanic systems in the NVZ. An extensive GPS survey was undertaken in 2013, with over 135 stations occupied. This data was evaluated in conjunction with data acquired since 2008, to generate a velocity field spanning this entire time period. In addition to an existing continuous GPS (cGPS) station, three cGPS stations were installed in the area in 2011-2012. The 2008-2013 GPS velocities were compared to earlier GPS results, and complementary analysis of InSAR images was undertaken. Earlier studies have shown that the Krafla caldera underwent uplift during 1984-1989, followed by subsidence. Since 1995, the maximum subsidence in Krafla has shifted from directly above the shallow magma chamber towards an array of boreholes (geothermal exploitation) in Leirbotnar. Similar subsidence has been observed around another array of boreholes in Bjarnaflag, 7 km further south. The most significant signal on the velocities calculated from campaign GPS data over the 5 year period, is plate spreading with an E-W velocity of about 12 mm/yr over a 30 km wide area. However it also shows an

  1. Geometry of the Turkey-Arabia and Africa-Arabia plate boundaries in the latest Miocene to Mid-Pliocene: the role of the Malatya-Ovacık Fault Zone in eastern Turkey

    NASA Astrophysics Data System (ADS)

    Westaway, R.; Demir, T.; Seyrek, A.

    2007-11-01

    We suggest a working hypothesis for the geometry of the strike-slip faults that formed the boundaries between the Turkish, African and Arabian plates in the latest Miocene to Mid-Pliocene (LMMP), between ~7-6 Ma and ~3.5 Ma. This geometry differed significantly from the modern geometry; the northern Dead Sea Fault Zone (DSFZ) was located east of its present line and the TR-AR boundary was formed by the Malatya-Ovacık Fault Zone (MOFZ), located well north of the modern East Anatolian Fault Zone (EAFZ). The MOFZ is potentially the most problematic aspect of such a scheme, given the dramatically different interpretations of it that have been proposed. However, the presently-available evidence, albeit limited, is consistent with our proposed interpretation. Significant differences between the proposed LMMP fault geometry and the modern geometry include, first, the transtensional geometry of the MOFZ, the modern EAFZ being typically a left-lateral transform fault zone but with localized transpression. Second, the MOFZ slip rate was much lower than the ~9-10 mm a-1 EAFZ slip rate; it is estimated as ~2-3 mm a-1, having produced no more than ~8 km of slip during its approximately three million year long activity. Third, unlike at present, there was no throughgoing linkage of left-lateral faulting between the LMMP DSFZ and the MOFZ; instead, the DSFZ terminated northward, and the MOFZ terminated southward, in a zone of localised crustal shortening adjoining the suture of the former Neotethys Ocean in the Kahramanmaraç-Pazarcık region of SE Turkey. The different motion of the Turkish plate relative to Arabia, and, thus, relative to Eurasia, means that senses and rates of crustal deformation can be expected to have been different during the LMMP phase from at present, throughout the eastern Mediterranean region.

  2. A specialized boundary element algorithm developed to calculate the state of stress in the Anza Gap, San Jacinto Fault Zone, Southern, CA

    SciTech Connect

    Aster, R.; Flores, R.; Fehler, M.

    1995-06-01

    The widely-used algorithm of Crouch and Starfield is unstable when used to solve our mixed boundary equation problem of interest. Altering the boundary conditions and correspondingly rearranging the system of equations to utilize double-sided boundary elements overcomes this drawback. The new algorithm described here is more physically realistic as in that it allows for rotation of the fault segments in the strain field resulting from satisfying the fault static shear strength condition. Preliminary test results indicate that a fault trifurcation gap model may describe the non-strike slip components to some of the seismicity.

  3. Crustal structure of the Churchill-Superior boundary zone between 80 and 98 deg W longitude from Magsat anomaly maps and stacked passes

    NASA Technical Reports Server (NTRS)

    Hall, D. H.; Millar, T. W.; Noble, I. A.

    1985-01-01

    A modeling technique using spherical shell elements and equivalent dipole sources has been applied to Magsat signatures at the Churchill-Superior boundary in Manitoba, Ontario, and Ungava. A large satellite magnetic anomaly (12 nT amplitude) on POGO and Magsat maps near the Churchill-Superior boundary was found to be related to the Richmond Gulf aulacogen. The averaged crustal magnetization in the source region is 5.2 A/m. Stacking of the magnetic traces from Magsat passes reveals a magnetic signature (10 nT amplitude) at the Churchill-Superior boundary in an area studied between 80 deg W and 98 deg W. Modeling suggests a steplike thickening of the crust on the Churchill side of the boundary in a layer with a magnetization of 5 A/m. Signatures on aeromagnetic maps are also found in the source areas for both of these satellite anomalies.

  4. Contact zone permeability at intrusion boundaries: New results from hydraulic testing and geophysical logging in the Newark Rift Basin, New York, USA

    USGS Publications Warehouse

    Matter, J.M.; Goldberg, D.S.; Morin, R.H.; Stute, M.

    2006-01-01

    Hydraulic tests and geophysical logging performed in the Palisades sill and the underlying sedimentary rocks in the NE part of the Newark Rift Basin, New York, USA, confirm that the particular transmissive zones are localized within the dolerite-sedimentary rock contact zone and within a narrow interval below this contact zone that is characterized by the occurrence of small layers of chilled dolerite. Transmissivity values determined from fluid injection, aquifer testing, and flowmeter measurements generally fall in the range of 8.1E-08 to 9.95E-06 m2/s and correspond to various scales of investigation. The analysis of acoustic and optical BHTV images reveals two primary fracture sets within the dolerite and the sedimentary rocks - subhorizontal fractures, intersected by subvertical ones. Despite being highly fractured either with subhorizontal, subvertical or both fracture populations, the dolerite above and the sedimentary rocks below the contact zone and the zone with the layers of chilled dolerite are significantly less conductive. The distribution of the particular conductive intervals is not a function of the two dominant fracture populations or their density but rather of the intrusion path of the sill. The intrusion caused thermal fracturing and cracking of both formations, resulting in higher permeability along the contact zone. ?? Springer-Verlag 2005.

  5. Study about AFS swerve mode

    NASA Astrophysics Data System (ADS)

    Liu, Hong; Jiang, Lanfang; Zhao, Qin; Wang, Li

    2009-11-01

    A swerving mathematical model was established after stating the shortage of the present AFS swerving algorithm. The conception of 'expected lighting distance' was extended to 'expected lighting bound' and approximate treatment of geometry of light beam falling to ground of headlamp was processed. The expected lighting bound was ascertained and the lighting range of turning angle of headlamp was calculated. The calculation formula of turning angle of headlamp was worked out. It was indicated that the turning angle of inside and outside of headlamp calculated by revised algorithm was reasonable by comparing calculation. Finally the control strategy about the turning angle of inside and outside headlamp when turning was worked out. It is of practical significance in promoting the active safety, reducing the traffic accidents caused by insufficient angle and range of irradiation of headlamp.

  6. Eaton AF5000+Genesis Communication Driver

    1995-05-25

    Communication driver allows the Genesis Control Series software to interact with Eaton AF5000+ frequency drives via RS-232 communications. All Eaton AF5000+ parameters that support communications are supported by the Genesis driver. Multidrop addressing to multiple units is available with the Genesis communication driver.

  7. Geometry of the Turkey-Arabia and Africa-Arabia plate boundaries in the latest Miocene to Mid-Pliocene: the role of the Malatya-Ovacık Fault Zone in eastern Turkey

    NASA Astrophysics Data System (ADS)

    Westaway, R.; Demir, T.; Seyrek, A.

    2008-08-01

    We suggest a working hypothesis for the geometry of the strike-slip faults that formed the boundaries between the Turkish, African and Arabian plates in the latest Miocene to Mid-Pliocene (LMMP), between ~7 6 Ma and ~3.5 Ma. This geometry differed significantly from the modern geometry; the northern Dead Sea Fault Zone (DSFZ) was located east of its present line and the TR-AR boundary was formed by the Malatya-Ovacık Fault Zone (MOFZ), located well north of the modern East Anatolian Fault Zone (EAFZ). The MOFZ is potentially the most problematic aspect of such a scheme, given the dramatically different interpretations of it that have been proposed. However, the presently-available evidence, albeit limited, is consistent with our proposed interpretation. Significant differences between the proposed LMMP fault geometry and the modern geometry include, first, the transtensional geometry of the MOFZ, the modern EAFZ being typically a left-lateral transform fault zone but with localized transpression. Second, the MOFZ slip rate was much lower than the ~9 10 mm a-1 EAFZ slip rate; it is estimated as ~2 3 mm a-1, having produced no more than ~8 km of slip during its approximately three million year long activity. The Euler vector is tentatively inferred to have involved relative rotation between the Turkish and Arabian Plates at ~0.85±0.15° Ma-1 about a pole at ~37.75±0.15° N, ~38.8±0.3° E. Third, unlike at present, there was no throughgoing linkage of left-lateral faulting between the LMMP DSFZ and the MOFZ; instead, the DSFZ terminated northward, and the MOFZ terminated southward, in a zone of localised crustal shortening adjoining the suture of the former Neotethys Ocean in the Kahramanmaraş-Pazarcık region of SE Turkey. The different motion of the Turkish plate relative to Arabia, and, thus, relative to Eurasia, means that senses and rates of crustal deformation can be expected to have been different during the LMMP phase from at present, throughout the

  8. Lithostratigraphic setting and P-T metamorphic evolution for the Dora Maira Massif along the Piedmont Zone boundary (middle Susa Valley, NW Alps)

    NASA Astrophysics Data System (ADS)

    Gasco, Ivano; Gattiglio, Marco; Borghi, Alessandro

    2011-07-01

    A new structural and petrological study, associated with a detailed geological mapping, allowed to better understand the tectonic relationships between the Dora Maira Massif and the Piedmont Zone in the middle Susa Valley. In the study area, a thick sequence of calcschists, previously attributed to the stratigraphic cover of the Dora Maira, is interpreted as belonging to the Piedmont Zone. Four deformation phases were identified: D1 represents the eclogite facies stage, D2 developed under greenschist facies conditions, transposed the early foliation and was responsible for the development of the regional schistosity S2. D3 is characterized by close to open folds with N dipping axial surfaces and finally, D4 developed macro-scale folds with E-dipping axial planes. Structural analyses allow to infer a relative timing for the tectonic contact between the two nappes which were coupled after the eclogite facies metamorphism but before the development of the S2 foliation under greenschist facies conditions. Petrographic investigation into metapelite samples permitted to identify two main metamorphic assemblages within the Dora Maira polymetamorphic basement: M1 (Phe + Pg + Cld + Grt + ChlI + Qtz + Rt) assemblage defines the S1 relict foliation, while M2 (Ms + Pg + Ab + ChlII + Qtz + Ilm ± Bt) assemblage is related to the regional foliation S2. PERPLE_X pseudosection modelling allowed to reconstruct a P-T path for a garnet-chloritoid-bearing micaschist from the northern part of the Dora Maira Massif, which reached eclogite facies conditions at 18-20 kbar and 515-525°C (M1/S1 event) and then was exhumed during increasing T (10-11 kbar and 555-565°C). The M2 assemblage defining the S2 regional foliation developed at P < 7 kbar and T < 575°C. According to the structural evolution, the tectonic coupling between Dora Maira and Piedmont Zone took place during exhumation along the subduction channel.

  9. STBC AF relay for unmanned aircraft system

    NASA Astrophysics Data System (ADS)

    Adachi, Fumiyuki; Miyazaki, Hiroyuki; Endo, Chikara

    2015-01-01

    If a large scale disaster similar to the Great East Japan Earthquake 2011 happens, some areas may be isolated from the communications network. Recently, unmanned aircraft system (UAS) based wireless relay communication has been attracting much attention since it is able to quickly re-establish the connection between isolated areas and the network. However, the channel between ground station (GS) and unmanned aircraft (UA) is unreliable due to UA's swing motion and as consequence, the relay communication quality degrades. In this paper, we introduce space-time block coded (STBC) amplify-and-forward (AF) relay for UAS based wireless relay communication to improve relay communication quality. A group of UAs forms single frequency network (SFN) to perform STBC-AF cooperative relay. In STBC-AF relay, only conjugate operation, block exchange and amplifying are required at UAs. Therefore, STBC-AF relay improves the relay communication quality while alleviating the complexity problem at UAs. It is shown by computer simulation that STBC-AF relay can achieve better throughput performance than conventional AF relay.

  10. The Dorsoventral Boundary of the Germinal Zone is a Specialized Niche for the Generation of Cortical Oligodendrocytes during a Restricted Temporal Window.

    PubMed

    Naruse, Masae; Ishino, Yugo; Kumar, Akhilesh; Ono, Katsuhiko; Takebayashi, Hirohide; Yamaguchi, Masahiro; Ishizaki, Yasuki; Ikenaka, Kazuhiro; Hitoshi, Seiji

    2016-06-01

    Oligodendrocyte precursor cells (OPCs) appear in the late embryonic brain, mature to become oligodendrocytes (OLs), and form myelin in the postnatal brain. Recently, it has been proposed that early-born OPCs derived from the ventral forebrain are eradicated postnatally and that late-born OLs predominate in the cortex of the adult mouse brain. However, intrinsic and extrinsic factors that specify the ability of self-renewing multipotent neural stem cells in the embryonic brain to generate cortical OL-lineage cells remain largely unknown. Using an inducible Cre/loxP system to permanently label Nestin- and Olig2-lineage cells, we identified that cortical OL-lineage cells start differentiating from neural stem cells within a restricted temporal window just prior to E16.5 through P10. We then showed, by means of electroporation of a Cre expression plasmid into the VZ/SVZ of E15.5 reporter mouse brains, that neural precursor cells in the dorsal VZ/SVZ are inhibited by Wnt signaling from contributing to cortical OLs in the adult brain. In contrast, neural precursor cells present in the dorsoventral boundary VZ/SVZ produce a significant amount of OLs in the adult cortex. Our results suggest that neural stem cells at this boundary are uniquely specialized to produce myelin-forming OLs in the cortex. PMID:26108613

  11. 49 CFR 71.8 - Mountain zone.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  12. 49 CFR 71.8 - Mountain zone.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  13. 49 CFR 71.8 - Mountain zone.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  14. 49 CFR 71.8 - Mountain zone.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  15. 49 CFR 71.8 - Mountain zone.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Mountain zone. 71.8 Section 71.8 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.8 Mountain zone. The fourth zone, the mountain standard time zone, includes that part of the United States that is west of...

  16. Geodetic constraints on active tectonics of the Western Mediterranean: Implications for the kinematics and dynamics of the Nubia-Eurasia plate boundary zone

    NASA Astrophysics Data System (ADS)

    Vernant, Philippe; Fadil, Abdelali; Mourabit, Taoufik; Ouazar, Driss; Koulali, Achraf; Davila, Jose Martin; Garate, Jorge; McClusky, Simon; Reilinger, Robert

    2010-04-01

    We present GPS observations in Morocco and adjacent areas of Spain from 15 continuous (CGPS) and 31 survey-mode (SGPS) sites extending from the stable part of the Nubian plate to central Spain. We determine a robust velocity field for the W Mediterranean that we use to constrain models for the Iberia-Nubia plate boundary. South of the High Atlas Mountain system, GPS motions are consistent with Nubia plate motions from prior geodetic studies. We constrain shortening in the Atlas system to <1.5 mm/yr, 95% confidence level. North of the Atlas Mountains, the GPS velocities indicate Nubia motion with respect to Eurasia, but also a component of motion normal to the direction of Nubia-Eurasia motion, consisting of southward translation of the Rif Mountains in N Morocco at rates exceeding 5 mm/yr. This southward motion appears to be directly related to Miocene opening of the Alboran Sea. The Betic Mountain system north of the Alboran Sea is characterized by WNW motion with respect to Eurasia at ˜1-2 mm/yr, paralleling Nubia-Eurasia relative motion. In addition, sites located in the Betics north of the southerly moving Rif Mountains also indicate a component of southerly motion with respect to Eurasia. We interpret this as indicating that deformation associated with Nubia-Eurasia plate motion extends into the southern Betics, but also that the Betic system may be affected by the same processes that are causing southward motion of the Rif Mountains south of the Alboran Sea. Kinematic modeling indicates that plate boundary geometries that include a boundary through the Straits of Gibraltar are most compatible with the component of motion in the direction of relative plate motion, but that two additional blocks (Alboran-Rif block, Betic Mountain block), independent of both Nubia and Eurasia are needed to account for the motions of the Rif and Betic Mountains normal to the direction of relative plate motion. We speculate that the southward motions of the Alboran-Rif and Betic

  17. The Influence of Temperature on Fault Strength and the Base of the Crustal Seismogenic Zone along the Pacific-North American Plate Boundary

    NASA Astrophysics Data System (ADS)

    Williams, C. F.

    2008-12-01

    A fundamental property of crustal seismicity is the depth confinement of earthquake nucleation. Although the frictional stability of seismogenic faults is a complex phenomenon with limited experimental evidence to constrain it, an important feature of the seismic-aseismic transition along the San Andreas and subsidiary fault systems in California is the consistency of temperature as the primary control, with the transition temperature averaging a relatively constant 350 to 400 °C over a fairly wide depth range (5 to 25 km) at many different locations. Along the active faults characterized by this constant transition temperature, the base of the seismogenic zone as defined by background seismicity is generally within approximately 2 km of the depth of hypocenters for significant earthquakes (e.g., 1971 M6.6 San Fernando, 1983 M6.4 Coalinga, 1984 M6.2 Morgan Hill, 1987 M5.9 Whittier Narrows, 1989 M6.9 Loma Prieta, 1992 M6.1 Joshua Tree, and 1994 M6.7 Northridge earthquakes). However, the fault zones ruptured by the 1992 M7.3 Landers, 1999 M7.1 Hector Mine and 2004 M6.0 Parkfield earthquakes deviate from this pattern in two potentially significant ways. First, the base of seismicity for these earthquakes appears to occur at a lower temperature (300 to 350 °C for Parkfield and less than 300 °C for Landers and Hector Mine). Second, for all three earthquakes the nucleation point of the main shock is on the order of 5 km shallower than the observed base of seismicity. Taken together, these two sets of observations indicate that the strength of the fault segments involved in these three earthquakes may not reach a maximum near the base of the seismogenic zone and that frictional stability on these fault segments is controlled by a combination of processes or properties of which temperature is only one, possibly less important, factor. Results from the recent SAFOD scientific drilling project highlight the potential role of serpentinite-rich fault gouge in altering fault

  18. Fault kinematics and active tectonics at the southeastern boundary of the eastern Alborz (Abr and Khij fault zones): Geodynamic implications for NNE Iran

    NASA Astrophysics Data System (ADS)

    Javidfakhr, Bita; Bellier, Olivier; Shabanian, Esmaeil; Siame, Lionel; Léanni, Laëtitia; Bourlès, Didier; Ahmadian, Seiran

    2011-10-01

    The Alborz is a region of active deformation within the Arabia-Eurasia collision zone. The Abr and the Khij Faults are two NE-trending left-lateral strike-slip faults in the eastern Alborz that correspond to the Shahrud fault system extended through an area of about 95 km × 55 km. Tectonic landforms typically associated with active strike-slip faults, such as deflected stream channels, offset ridges and fault scarps are documented along the mentioned faults. Detailed analyses of satellite images and digital topographic data accompanied by field surveys allowed us to measure horizontal offsets of about 420 ± 50 m and 400 ± 50 m for the Abr and Khij Faults, respectively. A total of 8 quartz-rich samples were sampled and dated from two different fan surfaces using in situ-produced 10Be cosmogenic dating method. Minimum exposure ages for the abandonment of the alluvial fan surfaces of 115 ± 14 kyr along the Abr Fault and of 230 ± 16 kyr along the Khij Fault imply that both faults are active with slip rates of about 3-4 mm yr -1 and 1-3 mm yr -1, respectively. The results of our study provide the first direct quantitative geological estimates of slip rate along these two active faults and place a new constraint on slip distribution between the faults in the eastern Alborz. Fault kinematic studies (from fault slip data) indicate a N35°E-trending maximum stress axis comprising a dominant strike-slip regime in agreement with the geomorphological analyses. The left-lateral strike-slip faulting along the Abr and Khij Faults and their associated fault zones in the eastern Alborz can be due to the westward component of motion of the South Caspian Basin with respect to Eurasia and Central Iran.

  19. Korean Atrial Fibrillation (AF) Network: Genetic Variants for AF Do Not Predict Ablation Success

    PubMed Central

    Choi, Eue-Keun; Park, Jae Hyung; Lee, Ji-Young; Nam, Chung Mo; Hwang, Min Ki; Uhm, Jae-Sun; Joung, Boyoung; Ko, Young-Guk; Lee, Moon-Hyoung; Lubitz, Steven A; Ellinor, Patrick T; Pak, Hui-Nam

    2015-01-01

    Background Genomewide association studies have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between top susceptibility loci and AF recurrence after ablation have not been examined in Asian populations. We examined whether the top single nucleotide polymorphisms (SNPs) at chromosomes 4q25 (PITX2), 16q22 (ZFHX3), and 1q21 (KCNN3) were associated with AF in a Korean population and whether these SNPs were associated with clinical outcomes after catheter ablation for AF. Methods and Results We determined the association between 4 SNPs and AF in 1068 AF patients who underwent catheter ablation (74.6% male, aged 57.5±10.9 years, 67.9% paroxysmal AF) and 1068 age- and sex-matched controls. The SNPs at the PITX2 and ZFHX3 loci, but not the KCNN3 locus, were significantly associated with AF (PITX2/rs6843082_G: odds ratio 3.41, 95% CI 2.55 to 4.55, P=1.32×10−16; PITX2/rs2200733_T: odds ratio 2.05, 95% CI 1.66 to 2.53, P=2.20×10−11; ZFHX3/rs2106261_A: odds ratio 2.33, 95% CI 1.87 to 2.91, P=3.75×10−14; KCNN3/rs13376333_T: odds ratio 1.74, 95% CI 0.93 to 3.25, P=0.085). Among those patients who underwent catheter ablation for AF, none of the top AF-associated SNPs were associated with long-term clinical recurrence of AF after catheter ablation. Conclusions SNPs at the PITX2 and ZFHX3 loci were strongly associated with AF in Korean patients. In contrast to prior reports, none of the 4 top AF-susceptibility SNPs predicted clinical recurrence after catheter ablation. PMID:26272656

  20. Variscan terrane boundaries in the Odenwald-Spessart basement, Mid-German Crystalline Zone: New evidence from ocean ridge, intraplate and arc-derived metabasaltic rocks

    NASA Astrophysics Data System (ADS)

    Will, T. M.; Lee, S.-H.; Schmädicke, E.; Frimmel, H. E.; Okrusch, M.

    2015-04-01

    The Mid-German Crystalline Zone is part of a large Variscan suture and consists of various basement complexes that are exposed in central Germany. New lithogeochemical and Sr-Nd-Pb isotope data obtained on various amphibolites from the Odenwald-Spessart basement show that their protoliths formed in different tectonic settings and were subsequently incorporated into a subduction zone prior to Variscan continental collision. Metabasic rocks from the northernmost Spessart and the western Odenwald are geochemically almost identical and their protoliths are interpreted to have formed in an extensional, possibly, a back-arc setting. The tholeiitic and calc-alkaline rocks have intermediate TiO2 concentrations and high Th/Nb ratios, typical of volcanic arc-type and/or subduction-fluid modified rocks. The Nd initial ratios are depleted (εNd330 Ma = 5.0-5.8) and Nd model ages range from 660 to 610 Ma, which points at juvenile crustal addition towards the end of the Neoproterozoic. The samples define a linear array in 206Pb/204Pb versus 207Pb/204Pb space. In contrast, the protoliths of the metabasic rocks from the southern and central Spessart formed either in an intraplate oceanic island or a continental arc setting. The alkaline intraplate rocks from the southern Spessart basement are very TiO2-rich and have very low Th/Nb ratios. The rocks have weakly depleted Nd initals (εNd330 Ma = 2.6-3.3) and Nd model ages between 870 and 810 Ma. In contrast, the central Spessart within-plate rocks have considerably lower TiO2 concentrations but higher Th/Nb ratios. In addition, these rocks are isotopically enriched (εNd330 Ma = - 13.1 to - 9.5) and have Palaeoproterozoic Nd model ages. The continental arc rocks from the central and southern Spessart basement have low TiO2 concentrations and variable Th/Nb ratios. Mostly negative Nd initials (εNd330 Ma = - 2.6 to + 0.9) and late Mesoproterozoic Nd model ages indicate that recycling of older crust or mixing of crustal components of

  1. Boundary Crossing and Boundary Objects

    ERIC Educational Resources Information Center

    Akkerman, Sanne F.; Bakker, Arthur

    2011-01-01

    Diversity and mobility in education and work present a paramount challenge that needs better conceptualization in educational theory. This challenge has been addressed by educational scholars with the notion of "boundaries", particularly by the concepts of "boundary crossing" and "boundary objects". Although studies on boundary crossing and…

  2. Degradation of AF1Q by chaperone-mediated autophagy

    SciTech Connect

    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru; Li, Huanjie; Cui, Taixing; Li Wang, Xing; Tang, Dongqi; Ji, Chunyan

    2014-09-10

    AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA. - Highlights: • Chaperone-mediated autophagy (CMA) is involved in the degradation of AF1Q. • Macroautophagy does not contribute to the AF1Q degradation. • AF1Q has a KFERQ-like motif that is recognized by CMA core components.

  3. AFS Estuaries Section - A Successful Partnership

    EPA Science Inventory

    The Estuaries Section of the American Fisheries Society offers travel awards to students in support of their attendance and presentations at the AFS meeting. Since 2007, the Southern Association of Marine Laboratories has partnered with the Estuaries Section to sponsor two stude...

  4. Health Information in Somali (af Soomaali): MedlinePlus

    MedlinePlus

    ... af Soomaali (Somali) Bilingual PDF Health Information Translations Animal Bites Animal Bites and Scratches Qaniinyada iyo Xagashada Xayawaanka - af ... Soomaali (Somali) Bilingual PDF Health Information Translations Radiation Therapy Preventing Infections When Your White Blood Cell Count ...

  5. Health Information in Somali (af Soomaali): MedlinePlus

    MedlinePlus

    ... Bilingual PDF Health Information Translations Appendectomy for a Child Qabsin-saarid ilmo - af Soomaali (Somali) Bilingual PDF ... Somali) Bilingual PDF Health Information Translations Asthma in Children Nebulizer Treatments Daawenta wal in Xaqiiqsanaan - af Soomaali ( ...

  6. 33 CFR 3.25-20 - Sector North Carolina Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.25-20 Section 3.25-20 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector North Carolina's office is located in Wilmington, NC. The boundary of Sector North Carolina's Marine Inspection Zone and Captain of the Port Zone starts...

  7. 33 CFR 3.55-15 - Sector San Diego Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.55-15 Section 3.55-15 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector San Diego's office is located in San Diego, CA. The boundaries of Sector San Diego's Marine Inspection Zone and Captain of the Port Zone start at a point...

  8. 33 CFR 3.55-15 - Sector San Diego Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.55-15 Section 3.55-15 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector San Diego's office is located in San Diego, CA. The boundaries of Sector San Diego's Marine Inspection Zone and Captain of the Port Zone start at a point...

  9. 33 CFR 3.55-15 - Sector San Diego Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.55-15 Section 3.55-15 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector San Diego's office is located in San Diego, CA. The boundaries of Sector San Diego's Marine Inspection Zone and Captain of the Port Zone start at a point...

  10. 33 CFR 3.25-20 - Sector North Carolina Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.25-20 Section 3.25-20 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector North Carolina's office is located in Wilmington, NC. The boundary of Sector North Carolina's Marine Inspection Zone and Captain of the Port Zone starts...

  11. 33 CFR 3.55-15 - Sector San Diego Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.55-15 Section 3.55-15 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector San Diego's office is located in San Diego, CA. The boundaries of Sector San Diego's Marine Inspection Zone and Captain of the Port Zone start at a point...

  12. 33 CFR 3.25-20 - Sector North Carolina Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Inspection Zone and Captain of the Port Zone. 3.25-20 Section 3.25-20 Navigation and Navigable Waters COAST... Inspection Zone and Captain of the Port Zone. Sector North Carolina's office is located in Wilmington, NC. The boundary of Sector North Carolina's Marine Inspection Zone and Captain of the Port Zone starts...

  13. Late middle ( ) Miocene Segmentation of an Eocene-early Miocene carbonate megabank on the Northern Nicaragua Rise tied to the tectonic activity at the North America/Caribbean plate boundary zone

    SciTech Connect

    Droxler, A.; Cunningham, A. ); Hine, A.C.; Hallock, P.; Duncan, D. ); Rosencrantz, E.; Buffler, R. ); Robinson, E. )

    1993-02-01

    The Northern Nicaragua Rise (NNR) is comprised today of the eastern Honduras/Nicaragua and southern Jamaica carbonate shelves, and a series of relatively small detached carbonate banks (i.e., Pedro, Rosalind, Serranilla, Diriangen, and Bawika Banks) separated from each other by intervening basins and seaways. The NNR basins and seaways, because of their common north trending orientation, have been previously interpreted as Paleocene, Eocene, and possibly Oligocene rifts, becoming progressively younger from the eastern to the western part of NNR. Results from three recent (1988 and 1992) high resolution seismic surveys within these major seaways and basins, (1) Walton Basin, (2) Pedro Channel, and (3) seaways and Serranilla Basin on the western side of the NNR, show that the present bank and basin configuration evolved from a once continuous megabank that covered the entire length of the NNR, including the Island of Jamaica from Eocene through early Miocene times. In the late middle ( ) Miocene, this megabank progressively broke up into a series of smaller banks, basins and seaways, mainly as the result of tectonic movements related to the overall strike-slip displacement within the North American and Caribbean Plate Boundary Zone of the Cayman Trough. At the same time (late middle Miocene), the most eastern portion of the megabank was uplifted and today forms most of central and south Jamaica. The timing of the megabank segmentation has tentatively been constrained by dating several blocks of shallow water limestone dredged from parts of the megabank outcropping on the sea floor of different seaways.

  14. Microfluidic Pumps Containing Teflon [Trademark] AF Diaphragms

    NASA Technical Reports Server (NTRS)

    Willis, Peter; White, Victor; Grunthaner, Frank; Ikeda, Mike; Mathies, Richard A.

    2009-01-01

    Microfluidic pumps and valves based on pneumatically actuated diaphragms made of Teflon AF polymers are being developed for incorporation into laboratory-on-a-chip devices that must perform well over temperature ranges wider than those of prior diaphragm-based microfluidic pumps and valves. Other potential applications include implanted biomedical microfluidic devices, wherein the biocompatability of Teflon AF polymers would be highly advantageous. These pumps and valves have been demonstrated to function stably after cycling through temperatures from -125 to 120 C. These pumps and valves are intended to be successors to similar prior pumps and valves containing diaphragms made of polydimethylsiloxane (PDMS) [commonly known as silicone rubber]. The PDMS-containing valves ae designed to function stably only within the temperature range from 5 to 80 C. Undesirably, PDMS membranes are somwehat porous and retain water. PDMS is especially unsuitable for use at temperatures below 0 C because the formation of ice crystals increases porosity and introduces microshear.

  15. Ground boundaries

    SciTech Connect

    Balluffi, R.W.; Bristowe, P.D.

    1990-01-01

    The present document is a progress report describing the work accomplished on the study of grain boundaries in Ag, Au, Ni, Si, and Ge. Research was focused on the following four major efforts: study of the atomic structure of grain boundaries by means of x-ray diffraction, transmission electron microscopy and computer modeling; grain boundary migration; short-circuit diffusion along grain boundaries; and development of Thin-Film Deposition/Bonding Apparatus for the manufacture of high purity bicrystals. 10 refs., 1 fig.

  16. Lithological units at the boundary zone between the Jining and Huai'an Complexes (central-northern margin of the North China Craton): A Paleoproterozoic tectonic mélange?

    NASA Astrophysics Data System (ADS)

    Wang, Luojuan; Guo, Jinghui; Peng, Peng; Liu, Fu; Windley, Brian F.

    2015-06-01

    In the central-northern margin of the North China Craton, the tectonic boundary between the Jining and Huai'an Complexes is well exposed in the Gushan area. In this boundary zone, exotic blocks of orthopyroxene-bearing monzonitic gneiss, garnet-bearing mafic granulite, marble, and calc-silicate were identified in the meta-psammitic and meta-pelitic matrix. The likely nature of the rock units is a tectonic mélange, which is a key to understand the tectonic evolution of the craton. In this paper, geochronological and geochemical studies have been carried out on representative lithologies from the Gushan area to discuss their petrogenesis and geodynamic settings. The opx-bearing monzonitic gneisses (U-Pb zircon emplacement age of 2.17 Ga) are high-K calc-alkaline to shoshonitic I-type rocks with trace-element magmatic arc signature. The trace elements, whole rock Sm-Nd and zircon Lu-Hf isotopes suggest that they were possibly derived from partial melting of Neoarchean lower crust (garnet amphibolite) in a continental arc. The protoliths of the garnet-bearing mafic granulites are inferred to have formed between 2.37 Ga and 1.95 Ga, possibly at 2.2 Ga. They show N-MORB geochemical affinity and were most likely produced by partial melting of spinel lherzolite in a mid-ocean ridge setting. Detrital zircons from one metapsammite sample (garnet-bearing quartzofeldspathic gneiss) yield nearly concordant 207Pb/206Pb ages ranging from 2.1 Ga to 2.0 Ga. In situ U-Pb and Hf isotopic data of zircons from the metapsammite sample support that the metasedimentary protoliths were probably derived from a mid-Paleoproterozoic continental arc. Three metamorphic age groups (1.95-1.93 Ga, 1.86-1.83 Ga, and 1.80 Ga) are revealed by the opx-bearing monzonitic gneisses, garnet-bearing mafic granulites, garnet-bearing quartzofeldspathic gneiss, and sillimanite-garnet-K-feldspar gneiss. The predominant group (1.95-1.93 Ga) is considered to record the age of near-peak granulite facies

  17. U2AF65 adapts to diverse pre-mRNA splice sites through conformational selection of specific and promiscuous RNA recognition motifs.

    PubMed

    Jenkins, Jermaine L; Agrawal, Anant A; Gupta, Ankit; Green, Michael R; Kielkopf, Clara L

    2013-04-01

    Degenerate splice site sequences mark the intron boundaries of pre-mRNA transcripts in multicellular eukaryotes. The essential pre-mRNA splicing factor U2AF(65) is faced with the paradoxical tasks of accurately targeting polypyrimidine (Py) tracts preceding 3' splice sites while adapting to both cytidine and uridine nucleotides with nearly equivalent frequencies. To understand how U2AF(65) recognizes degenerate Py tracts, we determined six crystal structures of human U2AF(65) bound to cytidine-containing Py tracts. As deoxy-ribose backbones were required for co-crystallization with these Py tracts, we also determined two baseline structures of U2AF(65) bound to the deoxy-uridine counterparts and compared the original, RNA-bound structure. Local structural changes suggest that the N-terminal RNA recognition motif 1 (RRM1) is more promiscuous for cytosine-containing Py tracts than the C-terminal RRM2. These structural differences between the RRMs were reinforced by the specificities of wild-type and site-directed mutant U2AF(65) for region-dependent cytosine- and uracil-containing RNA sites. Small-angle X-ray scattering analyses further demonstrated that Py tract variations select distinct inter-RRM spacings from a pre-existing ensemble of U2AF(65) conformations. Our results highlight both local and global conformational selection as a means for universal 3' splice site recognition by U2AF(65). PMID:23376934

  18. Boundary Layer

    NASA Technical Reports Server (NTRS)

    Loitsianskii. L. G.

    1956-01-01

    The fundamental, practically the most important branch of the modern mechanics of a viscous fluid or a gas, is that branch which concerns itself with the study of the boundary layer. The presence of a boundary layer accounts for the origin of the resistance and lift force, the breakdown of the smooth flow about bodies, and other phenomena that are associated with the motion of a body in a real fluid. The concept of boundary layer was clearly formulated by the founder of aerodynamics, N. E. Joukowsky, in his well-known work "On the Form of Ships" published as early as 1890. In his book "Theoretical Foundations of Air Navigation," Joukowsky gave an account of the most important properties of the boundary layer and pointed out the part played by it in the production of the resistance of bodies to motion. The fundamental differential equations of the motion of a fluid in a laminar boundary layer were given by Prandtl in 1904; the first solutions of these equations date from 1907 to 1910. As regards the turbulent boundary layer, there does not exist even to this day any rigorous formulation of this problem because there is no closed system of equations for the turbulent motion of a fluid. Soviet scientists have done much toward developing a general theory of the boundary layer, and in that branch of the theory which is of greatest practical importance at the present time, namely the study of the boundary layer at large velocities of the body in a compressed gas, the efforts of the scientists of our country have borne fruit in the creation of a new theory which leaves far behind all that has been done previously in this direction. We shall herein enumerate the most important results by Soviet scientists in the development of the theory of the boundary layer.

  19. Grain boundaries

    SciTech Connect

    Balluffi, R.W.; Bristowe, P.D.

    1991-01-01

    The present document is a progress report describing the work accomplished to date during the second year of our four-year grant (February 15, 1990--February 14, 1994) to study grain boundaries. The research was focused on the following three major efforts: Study of the atomic structure of grain boundaries by means of x-ray diffraction, transmission electron microscopy and computer modeling; study of short-circuit diffusion along grain boundaries; and development of a Thin-film Deposition/Bonding Apparatus for the manufacture of high purity bicrystals.

  20. 33 CFR 3.35-25 - Sector San Juan Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Zone and Captain of the Port Zone. 3.35-25 Section 3.35-25 Navigation and Navigable Waters COAST GUARD... CAPTAIN OF THE PORT ZONES Seventh Coast Guard District § 3.35-25 Sector San Juan Marine Inspection Zone and Captain of the Port Zone. Sector San Juan's office is located in San Juan, PR. The boundaries...

  1. 33 CFR 3.65-15 - Sector Portland Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Zone and Captain of the Port Zone. 3.65-15 Section 3.65-15 Navigation and Navigable Waters COAST GUARD... CAPTAIN OF THE PORT ZONES Thirteenth Coast Guard District § 3.65-15 Sector Portland Marine Inspection Zone and Captain of the Port Zone. Sector Portland's office is located in Portland, OR. The boundaries...

  2. 33 CFR 3.05-20 - Sector Southeastern New England Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Marine Inspection Zone and Captain of the Port Zone. 3.05-20 Section 3.05-20 Navigation and Navigable... England Marine Inspection Zone and Captain of the Port Zone. Sector Southeastern New England's office is located in Providence, RI. The boundaries of Sector Southeastern New England's Marine Inspection Zone...

  3. 33 CFR 3.35-10 - Sector Miami Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Zone and Captain of the Port Zone. 3.35-10 Section 3.35-10 Navigation and Navigable Waters COAST GUARD... CAPTAIN OF THE PORT ZONES Seventh Coast Guard District § 3.35-10 Sector Miami Marine Inspection Zone and Captain of the Port Zone. Sector Miami's office is located in Miami, FL. The boundaries of Sector...

  4. 46 CFR 42.30-15 - Tropical Zone.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Tropical Zone. 42.30-15 Section 42.30-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Zones, Areas, and Seasonal Periods § 42.30-15 Tropical Zone. (a) Northern boundary of the Tropical Zone. The northern boundary of the Tropical Zone...

  5. 46 CFR 42.30-15 - Tropical Zone.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Tropical Zone. 42.30-15 Section 42.30-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) LOAD LINES DOMESTIC AND FOREIGN VOYAGES BY SEA Zones, Areas, and Seasonal Periods § 42.30-15 Tropical Zone. (a) Northern boundary of the Tropical Zone. The northern boundary of the Tropical Zone...

  6. 4:2:1 conduction of an AF initiating trigger

    PubMed Central

    Kojodjojo, Pipin; Chong, Eric; Lim, Toon Wei; Seow, Swee Chong

    2015-01-01

    A 44 year old male with idiopathic dilated cardiomyopathy was undergoing persistent atrial fibrillation (AF) ablation. Following antral ablation, AF terminated into a regular narrow complex rhythm. Earliest activation was mapped to a focus in the superior vena cava (SVC) which was conducted in a 2:1 ratio to the atria which in turn was conducted with 2:1 ratio to the ventricles, resulting in an unusual 4:2:1 conduction of the SVC tachycardia. 1:1 conduction of the SVC tachycardia to the atrium preceded initiation of AF. During AF, SVC tachycardia continued unperturbed. Sinus rhythm was restored following catheter ablation of the focus. PMID:27134438

  7. 49 CFR 71.10 - Pacific zone.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Time Act of 1966 and Pub. L. 97-449, 15 U.S.C. 260-264; 49 CFR 1.59(a)). ... 49 Transportation 1 2014-10-01 2014-10-01 false Pacific zone. 71.10 Section 71.10 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.10 Pacific zone. The...

  8. 49 CFR 71.10 - Pacific zone.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Time Act of 1966 and Pub. L. 97-449, 15 U.S.C. 260-264; 49 CFR 1.59(a)). ... 49 Transportation 1 2012-10-01 2012-10-01 false Pacific zone. 71.10 Section 71.10 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.10 Pacific zone. The...

  9. 49 CFR 71.10 - Pacific zone.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Time Act of 1966 and Pub. L. 97-449, 15 U.S.C. 260-264; 49 CFR 1.59(a)). ... 49 Transportation 1 2010-10-01 2010-10-01 false Pacific zone. 71.10 Section 71.10 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.10 Pacific zone. The...

  10. 49 CFR 71.10 - Pacific zone.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Time Act of 1966 and Pub. L. 97-449, 15 U.S.C. 260-264; 49 CFR 1.59(a)). ... 49 Transportation 1 2011-10-01 2011-10-01 false Pacific zone. 71.10 Section 71.10 Transportation Office of the Secretary of Transportation STANDARD TIME ZONE BOUNDARIES § 71.10 Pacific zone. The...

  11. AF4 and AF4N protein complexes: recruitment of P-TEFb kinase, their interactome and potential functions

    PubMed Central

    Scholz, Bastian; Kowarz, Eric; Rössler, Tanja; Ahmad, Khalil; Steinhilber, Dieter; Marschalek, Rolf

    2015-01-01

    AF4/AFF1 and AF5/AFF4 are the molecular backbone to assemble “super-elongation complexes” (SECs) that have two main functions: (1) control of transcriptional elongation by recruiting the positive transcription elongation factor b (P-TEFb = CyclinT1/CDK9) that is usually stored in inhibitory 7SK RNPs; (2) binding of different histone methyltransferases, like DOT1L, NSD1 and CARM1. This way, transcribed genes obtain specific histone signatures (e.g. H3K79me2/3, H3K36me2) to generate a transcriptional memory system. Here we addressed several questions: how is P-TEFb recruited into SEC, how is the AF4 interactome composed, and what is the function of the naturally occuring AF4N protein variant which exhibits only the first 360 amino acids of the AF4 full-length protein. Noteworthy, shorter protein variants are a specific feature of all AFF protein family members. Here, we demonstrate that full-length AF4 and AF4N are both catalyzing the transition of P-TEFb from 7SK RNP to their N-terminal domain. We have also mapped the protein-protein interaction network within both complexes. In addition, we have first evidence that the AF4N protein also recruits TFIIH and the tumor suppressor MEN1. This indicate that AF4N may have additional functions in transcriptional initiation and in MEN1-dependend transcriptional processes. PMID:26171280

  12. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 14 2013-01-01 2013-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  13. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 14 2012-01-01 2012-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  14. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  15. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  16. 7 CFR Exhibits A-F to Subpart A... - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 14 2014-01-01 2014-01-01 false A Exhibits A-F to Subpart A of Part 1955 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE... Real and Chattel Property Exhibits A-F to Subpart A of Part 1955...

  17. Part III: AFS - A Secure Distributed File System

    SciTech Connect

    Wachsmann, A.; /SLAC

    2005-06-29

    AFS is a secure distributed global file system providing location independence, scalability and transparent migration capabilities for data. AFS works across a multitude of Unix and non-Unix operating systems and is used at many large sites in production for many years. AFS still provides unique features that are not available with other distributed file systems even though AFS is almost 20 years old. This age might make it less appealing to some but with IBM making AFS available as open-source in 2000, new interest in use and development was sparked. When talking about AFS, people often mention other file systems as potential alternatives. Coda (http://www.coda.cs.cmu.edu/) with its disconnected mode will always be a research project and never have production quality. Intermezzo (http://www.inter-mezzo.org/) is now in the Linux kernel but not available for any other operating systems. NFSv4 (http://www.nfsv4.org/) which picked up many ideas from AFS and Coda is not mature enough yet to be used in serious production mode. This article presents the rich features of AFS and invites readers to play with it.

  18. Space Boundary Tool (SBT)

    2012-07-01

    SBT is an application that automatically calculates thermal zone boundaries suitable for input to the EnergyPlus simulation engine from building element and space geometry defined in IFC. SBT has multiple components. There is a general computational core, a DLL for reading and writing IFC files, and a GUI front end. The GUI also has the capability to create ready-to-simulate IDF files for EnergyPlus. Hardware req: PC; Operating Syst/Version: MSVC++2010; Type of files: source code; Documentation:more » User Manual (Electronic).« less

  19. Toward a petabyte-scale AFS service at CERN

    NASA Astrophysics Data System (ADS)

    van der Ster, Daniel; Moscicki, Jakub T.; Wiebalck, Arne

    2014-06-01

    AFS is a mature and reliable storage service at CERN, having worked for more than 20 years as the provider of Unix home directories and project areas. Recently, the AFS service has grown at unprecedented rates (200% in the past year); this growth was unlocked thanks to innovations in both the hardware and software components of our file servers. This work presents how AFS is used at CERN and how the service offering is evolving with the increasing storage needs of its local and remote user communities. In particular, we demonstrate the usage patterns for home directories, workspaces and project spaces, as well as show the daily work which is required to rebalance data and maintaining stability and performance. Finally, we highlight some recent changes and optimisations made to the AFS Service, thereby revealing how AFS can possibly operate at all while being subjected to frequent-almost DDOS-like-attacks from its users.

  20. Habitable zones and UV habitable zones around host stars

    NASA Astrophysics Data System (ADS)

    Guo, Jianpo; Zhang, Fenghui; Zhang, Xianfei; Han, Zhanwen

    2010-01-01

    Ultraviolet radiation is a double-edged sword to life. If it is too strong, the terrestrial biological systems will be damaged. And if it is too weak, the synthesis of many biochemical compounds cannot go along. We try to obtain the continuous ultraviolet habitable zones, and compare the ultraviolet habitable zones with the habitable zones of host stars. Using the boundary ultraviolet radiation of ultraviolet habitable zone, we calculate the ultraviolet habitable zones of host stars with masses from 0.08 to 4.00 M ⊙. For the host stars with effective temperatures lower than 4,600 K, the ultraviolet habitable zones are closer than the habitable zones. For the host stars with effective temperatures higher than 7,137 K, the ultraviolet habitable zones are farther than the habitable zones. For a hot subdwarf as a host star, the distance of the ultraviolet habitable zone is about ten times more than that of the habitable zone, which is not suitable for the existence of life.

  1. 15 CFR 922.130 - Boundary.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... subpart. (b) The Davidson Seamount Management Zone is also part of the Sanctuary. This area, bounded by geodetic lines connecting a rectangle centered on the top of the Davidson Seamount, consists of... County. Exact coordinates for the Davidson Seamount Management Zone boundary are provided in appendix...

  2. 15 CFR 922.130 - Boundary.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... subpart. (b) The Davidson Seamount Management Zone is also part of the Sanctuary. This area, bounded by geodetic lines connecting a rectangle centered on the top of the Davidson Seamount, consists of... County. Exact coordinates for the Davidson Seamount Management Zone boundary are provided in appendix...

  3. 15 CFR 922.130 - Boundary.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... subpart. (b) The Davidson Seamount Management Zone is also part of the Sanctuary. This area, bounded by geodetic lines connecting a rectangle centered on the top of the Davidson Seamount, consists of... County. Exact coordinates for the Davidson Seamount Management Zone boundary are provided in appendix...

  4. 15 CFR 922.130 - Boundary.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... subpart. (b) The Davidson Seamount Management Zone is also part of the Sanctuary. This area, bounded by geodetic lines connecting a rectangle centered on the top of the Davidson Seamount, consists of... County. Exact coordinates for the Davidson Seamount Management Zone boundary are provided in Appendix...

  5. 15 CFR 922.130 - Boundary.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... subpart. (b) The Davidson Seamount Management Zone is also part of the Sanctuary. This area, bounded by geodetic lines connecting a rectangle centered on the top of the Davidson Seamount, consists of... County. Exact coordinates for the Davidson Seamount Management Zone boundary are provided in appendix...

  6. 33 CFR 165.105 - Security Zones; Passenger Vessels, Portland, Maine, Captain of the Port Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., Maine, Captain of the Port zone as delineated in 33 CFR 3.05-15. (b) Location. The following areas are... person may swim upon or below the surface of the water within the boundaries of these security zones... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zones; Passenger...

  7. Boundary issues

    NASA Astrophysics Data System (ADS)

    Townsend, Alan R.; Porder, Stephen

    2011-03-01

    What is our point of no return? Caesar proclaimed 'the die is cast' while crossing the Rubicon, but rarely does modern society find so visible a threshold in our continued degradation of ecosystems and the services they provide. Humans have always used their surroundings to make a living— sometimes successfully, sometimes not (Diamond 2005)—and we intuitively know that there are boundaries to our exploitation. But defining these boundaries has been a challenge since Malthus first prophesied that nature would limit the human population (Malthus 1798). In 2009, Rockström and colleagues tried to quantify what the 6.8 billion (and counting) of us could continue to get away with, and what we couldn't (Rockström et al 2009). In selecting ten 'planetary boundaries', the authors contend that a sustainable human enterprise requires treating a number of environmental thresholds as points of no return. They suggest we breach these Rubicons at our own peril, and that we've already crossed three: biodiversity loss, atmospheric CO2, and disruption of the global nitrogen (N) cycle. As they clearly hoped, the very act of setting targets has provoked scientific inquiry about their accuracy, and about the value of hard targets in the first place (Schlesinger 2009). Such debate is a good thing. Despite recent emphasis on the science of human-ecosystem interactions, understanding of our planetary boundaries is still in its infancy, and controversy can speed scientific progress (Engelhardt and Caplan 1987). A few weeks ago in this journal, Carpenter and Bennett (2011) took aim at one of the more controversial boundaries in the Rockström analysis: that for human alteration of the global phosphorus (P) cycle. Rockström's group chose riverine P export as the key indicator, suggesting that humans should not exceed a value that could trigger widespread marine anoxic events—and asserting that we have not yet crossed this threshold. There are defensible reasons for a marine

  8. Albedo Boundary

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-510, 11 October 2003

    The sharp, nearly straight line that runs diagonally across the center of this April 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image is an albedo boundary. Albedois a term that refers to reflectance of sunlight. A surface with a low albedo is one that appears dark because it reflects less light than a high albedo (bright) surface. On Mars, albedo boundaries occur between two materials of differing texture, particle size, or composition, or some combination of these three factors. The boundary shown here is remarkable because it is so sharp and straight. This is caused by wind. Most likely, the entire surface was once covered with the lower-albedo (darker) material that is now seen in the upper half of the image. At some later time, wind stripped away this darker material from the surfaces in the lower half of the image. The difference in albedo here might be related to composition, and possibly particle size. This picture is located near the southwest rim of Schiaparelli Basin at 5.5oS, 345.9oW. The picture covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the left.

  9. An Implicit LU/AF FDTD Method

    NASA Technical Reports Server (NTRS)

    Beggs, John H.; Briley, W. Roger

    2001-01-01

    There has been some recent work to develop two and three-dimensional alternating direction implicit (ADI) FDTD schemes. These ADI schemes are based upon the original ADI concept developed by Peaceman and Rachford and Douglas and Gunn, which is a popular solution method in Computational Fluid Dynamics (CFD). These ADI schemes work well and they require solution of a tridiagonal system of equations. A new approach proposed in this paper applies a LU/AF approximate factorization technique from CFD to Maxwell s equations in flux conservative form for one space dimension. The result is a scheme that will retain its unconditional stability in three space dimensions, but does not require the solution of tridiagonal systems. The theory for this new algorithm is outlined in a one-dimensional context for clarity. An extension to two and threedimensional cases is discussed. Results of Fourier analysis are discussed for both stability and dispersion/damping properties of the algorithm. Results are presented for a one-dimensional model problem, and the explicit FDTD algorithm is chosen as a convenient reference for comparison.

  10. Prevention of Obesity and Insulin Resistance by Estrogens Requires ERα Activation Function-2 (ERαAF-2), Whereas ERαAF-1 Is Dispensable

    PubMed Central

    Handgraaf, Sandra; Riant, Elodie; Fabre, Aurélie; Waget, Aurélie; Burcelin, Rémy; Lière, Philippe; Krust, Andrée; Chambon, Pierre; Arnal, Jean-François; Gourdy, Pierre

    2013-01-01

    The beneficial metabolic actions of estrogen-based therapies are mainly mediated by estrogen receptor α (ERα), a nuclear receptor that regulates gene transcription through two activation functions (AFs): AF-1 and AF-2. Using mouse models deleted electively for ERαAF-1 (ERαAF-1°) or ERαAF-2 (ERαAF-2°), we determined their respective roles in the actions of estrogens on body composition and glucose homeostasis in response to either a normal diet or a high-fat diet (HFD). ERαAF-2° males and females developed accelerated weight gain, massive adiposity, severe insulin resistance, and glucose intolerance—quite reminiscent of the phenotype observed in mice deleted for the entire ERα protein (ERα−/−). In striking contrast, ERαAF-1° and wild-type (wt) mice shared a similar metabolic phenotype. Accordingly, 17β-estradiol administration regulated key metabolic genes in insulin-sensitive tissues and conferred a strong protection against HFD-induced metabolic disturbances in wt and ERαAF-1° ovariectomized mice, whereas these actions were totally abrogated in ERαAF-2° and ERα−/− mice. Thus, whereas both AFs have been previously shown to contribute to endometrial and breast cancer cell proliferation, the protective effect of estrogens against obesity and insulin resistance depends on ERαAF-2 but not ERαAF-1, thereby delineating new options for selective modulation of ERα. PMID:23903353

  11. Tuning the Music: Acoustic Force Spectroscopy (AFS) 2.0.

    PubMed

    Kamsma, Douwe; Creyghton, Ramon; Sitters, Gerrit; Wuite, Gijs J L; Peterman, Erwin J G

    2016-08-01

    AFS is a recently introduced high-throughput single-molecule technique that allows studying structural and mechanochemical properties of many biomolecules in parallel. To further improve the method, we developed a modelling tool to optimize the layer thicknesses, and a calibration method to experimentally validate the modelled force profiles. After optimization, we are able to apply 350pN on 4.5μm polystyrene beads, without the use of an amplifier, at the coverslip side of the AFS chip. Furthermore, we present the use of a transparent piezo to generate the acoustic force and we show that AFS can be combined with high-NA oil or water-immersion objectives. With this set of developments AFS will be applicable to a broad range of single-molecule experiments. PMID:27163865

  12. Boundary issues

    NASA Astrophysics Data System (ADS)

    Townsend, Alan R.; Porder, Stephen

    2011-03-01

    What is our point of no return? Caesar proclaimed 'the die is cast' while crossing the Rubicon, but rarely does modern society find so visible a threshold in our continued degradation of ecosystems and the services they provide. Humans have always used their surroundings to make a living— sometimes successfully, sometimes not (Diamond 2005)—and we intuitively know that there are boundaries to our exploitation. But defining these boundaries has been a challenge since Malthus first prophesied that nature would limit the human population (Malthus 1798). In 2009, Rockström and colleagues tried to quantify what the 6.8 billion (and counting) of us could continue to get away with, and what we couldn't (Rockström et al 2009). In selecting ten 'planetary boundaries', the authors contend that a sustainable human enterprise requires treating a number of environmental thresholds as points of no return. They suggest we breach these Rubicons at our own peril, and that we've already crossed three: biodiversity loss, atmospheric CO2, and disruption of the global nitrogen (N) cycle. As they clearly hoped, the very act of setting targets has provoked scientific inquiry about their accuracy, and about the value of hard targets in the first place (Schlesinger 2009). Such debate is a good thing. Despite recent emphasis on the science of human-ecosystem interactions, understanding of our planetary boundaries is still in its infancy, and controversy can speed scientific progress (Engelhardt and Caplan 1987). A few weeks ago in this journal, Carpenter and Bennett (2011) took aim at one of the more controversial boundaries in the Rockström analysis: that for human alteration of the global phosphorus (P) cycle. Rockström's group chose riverine P export as the key indicator, suggesting that humans should not exceed a value that could trigger widespread marine anoxic events—and asserting that we have not yet crossed this threshold. There are defensible reasons for a marine

  13. Tidal Boundary Conditions in SEAWAT

    USGS Publications Warehouse

    Mulligan, Ann E.; Langevin, Christian; Post, Vincent E.A.

    2011-01-01

    SEAWAT, a U.S. Geological Survey groundwater flow and transport code, is increasingly used to model the effects of tidal motion on coastal aquifers. Different options are available to simulate tidal boundaries but no guidelines exist nor have comparisons been made to identify the most effective approach. We test seven methods to simulate a sloping beach and a tidal flat. The ocean is represented in one of the three ways: directly using a high hydraulic conductivity (high-K) zone and indirect simulation via specified head boundaries using either the General Head Boundary (GHB) or the new Periodic Boundary Condition (PBC) package. All beach models simulate similar water fluxes across the upland boundary and across the sediment-water interface although the ratio of intertidal to subtidal flow is different at low tide. Simulating a seepage face results in larger intertidal fluxes and influences near-shore heads and salinity. Major differences in flow occur in the tidal flat simulations. Because SEAWAT does not simulate unsaturated flow the water table only rises via flow through the saturated zone. This results in delayed propagation of the rising tidal signal inland. Inundation of the tidal flat is delayed as is flow into the aquifer across the flat. This is severe in the high-K and PBC models but mild in the GHB models. Results indicate that any of the tidal boundary options are fine if the ocean-aquifer interface is steep. However, as the slope of that interface decreases, the high-K and PBC approaches perform poorly and the GHB boundary is preferable.

  14. Origin of the Low Velocity Zone

    NASA Astrophysics Data System (ADS)

    Stixrude, L. P.; Lithgow-Bertelloni, C. R.

    2014-12-01

    The origin of the low velocity zone is still not well understood, although the mechanisms responsible have important implications for the thermal evolution of the Earth and the origin of plate tectonics. The null hypothesis (a geotherm consisting of an adiabat and a conductive thermal boundary layer, and free of melt, water, and attenuation) accounts for many properties of the low velocity zone, including the depth at which the minimum velocity occurs and its variation with age, but the value of the minimum velocity is greater than that seen by seismology (the velocity deficit). Attenuation, as found in global seismic attenuation tomography, can explain much of the velocity deficit, but still leaves two features of the boundaries of the low velocity zone unexplained: an apparently abrupt upper boundary to the low velocity (G discontinuity, sometimes also associated with the "lithosphere-asthenosphere boundary"), and a high gradient zone beneath in which velocity increases with depth very rapidly. Here we show that by adding to the null hypothesis attenuation as recently measured experimentally, the entire velocity deficit is explained. Moreover, the upper boundary of the low velocity zone is remarkably abrupt, although possibly less sharp than receiver function analyses indicate. The high gradient zone is explained by variations in the entropy with depth, i.e. cooling with increasing depth at depths beneath the low velocity zone, a property of the geotherm that is expected on the basis of mantle convection simulations.

  15. Helena banks strike-slip(. ) fault and the relation to other Cenozoic faults along reactivated Triassic(. ) basin boundary fault zones in the Charleston, South Carolina, earthquake area - results from a marine high-resolution multichannel seismic-reflection survey

    SciTech Connect

    Behrendt, J.C.; Yuan, A.

    1985-01-01

    In 1981, the USGS conducted a high-resolution multichannel seismic (MCS) survey offshore of Charleston, South Carolina, to study the relation of Cenozoic faulting to future earthquake hazard. High-angle reverse displacement of Coastal Plain sedimentary rock indicating a linear increase with depth of 51 +/- 12 m/km is observed on the reflection profiles. This is similar to the Gants and Cooke faults in the meizoseismal area of the 1886 Charleston earthquake. The authors interpret these results to indicate that the stress field cannot have varied significantly in direction or in magnitude from Late Cretaceous time to Miocene or Pliocene time in the region. The HBF zone trends N 66/sup 0/ E; it comprises several 15- to 40-km-long segments that trend from N 68/sup 0/ E to N 77/sup 0/ E. The en-echelon pattern of the segments is compatible with left-lateral strike-slip and is thus consistent with the present northeast-trending maximum compressional stress field. The HBF zone appears to be an obliquely compressional reactivation of a tensional Triassic(.) fault zone bounding the Triassic(.) Kiawah Basin that has been identified on several MCS profiles. Similarly, the northeast-trending Gants reverse or strike-slip fault was probably reactivated from an old tensional fault bounding the Jedburg Triassic(.) basin in the 1886 meizoseismal area.

  16. Modelling the transitional boundary layer

    NASA Technical Reports Server (NTRS)

    Narasimha, R.

    1990-01-01

    Recent developments in the modelling of the transition zone in the boundary layer are reviewed (the zone being defined as extending from the station where intermittency begins to depart from zero to that where it is nearly unity). The value of using a new non-dimensional spot formation rate parameter, and the importance of allowing for so-called subtransitions within the transition zone, are both stressed. Models do reasonably well in constant pressure 2-dimensional flows, but in the presence of strong pressure gradients further improvements are needed. The linear combination approach works surprisingly well in most cases, but would not be so successful in situations where a purely laminar boundary layer would separate but a transitional one would not. Intermittency-weighted eddy viscosity methods do not predict peak surface parameters well without the introduction of an overshooting transition function whose connection with the spot theory of transition is obscure. Suggestions are made for further work that now appears necessary for developing improved models of the transition zone.

  17. Effects of Iron Depletion on CALM-AF10 Leukemias

    PubMed Central

    Heath, Jessica L.; Weiss, Joshua M.

    2014-01-01

    Iron, an essential nutrient for cellular growth and proliferation, enters cells via clathrin-mediated endocytosis (CME). The clathrin assembly lymphoid myeloid (CALM) protein plays an essential role in the cellular import of iron by CME. CALM-AF10 leukemias harbor a single copy of the normal CALM gene, and may therefore be more sensitive to the growth inhibitory effect of iron restriction compared with normal hematopoietic cells. We found that Calm heterozygous (CalmHET) murine fibroblasts exhibit signs of iron deficiency, with increased surface transferrin receptor (sTfR) levels and reduced growth rates. CalmHET hematopoietic cells are more sensitive in vitro to iron chelators than their wild type counterparts. Iron chelation also displayed toxicity towards cultured CalmHET CALM-AF10 leukemia cells and this effect was additive to that of chemotherapy. In mice transplanted with CalmHET CALM-AF10 leukemia, we found that dietary iron restriction reduces tumor burden in the spleen. However, dietary iron restriction, used alone or in conjunction with chemotherapy, did not increase survival of mice with CalmHET CALM-AF10 leukemia. In summary, while Calm heterozygosity results in iron deficiency and increased sensitivity to iron chelation in vitro, our data in mice do not suggest that iron depletion strategies would be beneficial for the therapy of CALM-AF10 leukemia patients. PMID:25193880

  18. 33 CFR 165.105 - Security Zones; Passenger Vessels, Portland, Maine, Captain of the Port Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Maine, Captain of the Port zone as delineated in 33 CFR 3.05-15. (b) Location. The following areas are... person may swim upon or below the surface of the water within the boundaries of these security...

  19. Local post-harvest practices associated with aflatoxin and fumonisin contamination of maize in three agro ecological zones of Tanzania.

    PubMed

    Kamala, Analice; Kimanya, Martin; Haesaert, Geert; Tiisekwa, Bendantuguka; Madege, Richard; Degraeve, Szanne; Cyprian, Cypriana; De Meulenaer, Bruno

    2016-01-01

    A survey was undertaken of a total of 120 farmers, 40 from each of the three studied agro-ecological zones of Tanzania, to determine local post-harvest management practices associated with aflatoxin (AF) and fumonisin (FB) contamination of maize. Data on practices (collected using a structured questionnaire) and maize samples were obtained from each of the 120 farmers. FB and AF contamination in the samples were analysed by HPLC. A total of 45% and 85% of maize samples were positive for AF and FB respectively, with levels ranging from 0.1 to 269 μg kg(-1) for AF and from 49 to 18 273 μg kg(-1) for FBs. Significant differences in contamination level were observed among the three agro-ecological zones. Farmers in the three agro-ecological zones practised similar practices in varying degrees. Drying, sorting and protecting maize against insect infestation are practices that showed significant association with AF or FB contamination of maize. Drying maize on mat/raised platform, sorting (damaged, discoloured and moulded grains) and application of synthetic insecticides during storage are practices that were associated with less contamination of maize with AF and FB. The results can be used to advise on effective post-harvest strategies for prevention of AF and FB contamination of maize in rural Tanzania. PMID:26795400

  20. RNA structure replaces the need for U2AF2 in splicing

    PubMed Central

    Lin, Chien-Ling; Taggart, Allison J.; Lim, Kian Huat; Cygan, Kamil J.; Ferraris, Luciana; Creton, Robbert; Huang, Yen-Tsung; Fairbrother, William G.

    2016-01-01

    RNA secondary structure plays an integral role in catalytic, ribosomal, small nuclear, micro, and transfer RNAs. Discovering a prevalent role for secondary structure in pre-mRNAs has proven more elusive. By utilizing a variety of computational and biochemical approaches, we present evidence for a class of nuclear introns that relies upon secondary structure for correct splicing. These introns are defined by simple repeat expansions of complementary AC and GT dimers that co-occur at opposite boundaries of an intron to form a bridging structure that enforces correct splice site pairing. Remarkably, this class of introns does not require U2AF2, a core component of the spliceosome, for its processing. Phylogenetic analysis suggests that this mechanism was present in the ancestral vertebrate lineage prior to the divergence of tetrapods from teleosts. While largely lost from land dwelling vertebrates, this class of introns is found in 10% of all zebrafish genes. PMID:26566657

  1. Stability analysis of intermediate boundary conditions in approximate factorization schemes

    NASA Technical Reports Server (NTRS)

    South, J. C., Jr.; Hafez, M. M.; Gottlieb, D.

    1986-01-01

    The paper discusses the role of the intermediate boundary condition in the AF2 scheme used by Holst for simulation of the transonic full potential equation. It is shown that the treatment suggested by Holst led to a restriction on the time step and ways to overcome this restriction are suggested. The discussion is based on the theory developed by Gustafsson, Kreiss, and Sundstrom and also on the von Neumann method.

  2. Regional variations in seismic boundaries

    NASA Astrophysics Data System (ADS)

    Shumlyanska, Ludmila

    2010-05-01

    Dividing of the Earth into zones in the frame one-dimensional velocity model was proposed Jeffreys and Gutenberg is the first half of XX century. They recovered the following zones: A - the crust; B - zone in the depth interval 33-413 km, C - zone 413-984 km, D - zone 984-2898 km, E - 2898-4982 km, F - 4982-5121 km, G - 5121-6371 km (centre of the Earth). These zones differ in their seismic properties. Later, zone D was divided to the areas D' (984-2700 km) and D" (2700-2900 km). At present, this scheme is significantly modified and only the layer D" is in wide use. The more seismological studies are carried out, the more seismic boundaries appear. Boundaries at 410, 520, 670, and 2900 km, at which increase in the velocity of the seismic waves is particularly noticeable are considered as having global significance. Moreover, there are indications of the existence of geophysical boundaries at 800, 1200-1300, 1700, 1900-2000 km. Using 3D P-velocity model of the mantle based on Taylor approximation method for solving of the inverse kinematics multi-dimensional seismic task we have obtained seismic boundaries for the area covering 20-55° E × 40-55° N. Data on the time of first arrivals of P waves from earthquakes and nuclear explosions recorded at ISC stations during 1964-2002 were used as input to construct a 3-D model. The model has two a priori limits: 1) the velocity is a continuous function of spatial coordinates, 2) the function v(r)/r where r is a radius in the spherical coordinate system r, φ, λ decreases with depth. The first limitation is forced since velocity leaps can not be sustainably restored from the times of first arrival; the second one follows from the nature of the observed data. Results presented as horizontal sections of the actual velocity every 25 km in the depth interval 850-2850 km, and as the longitudinal and latitudinal sections of the discrepancy on the 1-D reference model, obtained as a result of solving of the inversion task at 1

  3. AF-GEOSpace Version 2.5: Space Environment Software

    NASA Astrophysics Data System (ADS)

    Hilmer, R. V.; Hall, T.; Roth, C.; Ling, A.; Ginet, G. P.; Madden, D.

    2010-12-01

    AF-GEOSpace is a graphics-intensive software program with space environment models and applications developed by the Space Weather Center of Excellence at AFRL. The software addresses a wide range of physical domains, e.g., solar disturbance propagation, geomagnetic field and radiation belt configurations, auroral particle precipitation, and ionospheric scintillation. AF-GEOSpace has become a platform for developing and prototyping space weather visualization products. The new AF-GEOSpace Version 2.5 (release scheduled for 2010) expands on the content of Version 2.1 by including modules addressing the following new topics: (1) energetic proton maps for the South Atlantic Anomaly (from Ginet et al. [2007]), (2) GPS scintillation outage simulation tools, (3) magnetopause location determination (Shue et al. [1998]), (4) a plasmasphere model (Global Core Plasma Model, 2009 version based on Gallagher et al. [2000]), (5) a standard ionospheric model (International Reference Ionosphere 2007), (6) the CAMMICE/MICS model of inner magnetosphere plasma population (based on Roeder et al. [2005]), (7) magnetic field models (e.g., Tsyganenko and Sitnov [2005]), and (8) loading and displaying externally-produced 3D gridded data sets within AF-GEOSpace. Improvements to existing Version 2.1 capabilities include: (1) a 2005 update to the geomagnetic cutoff rigidity model of Smart and Shea [2003], (2) a 2005 update to the ionospheric scintillation Wide-Band Model (WBMOD) of Secan and Bussey [1994], and (3) improved magnetic field flux mapping options for the existing set of AF-GEOSpace radiation belt models. A basic review of these new AF-GEOSpace capabilities will be provided. To obtain a copy of the software, please contact the first author.

  4. AF-GEOSpace Version 2.1 Release

    NASA Astrophysics Data System (ADS)

    Hilmer, R. V.; Ginet, G. P.; Hall, T.; Holeman, E.; Madden, D.; Perry, K. L.; Tautz, M.; Roth, C.

    2006-05-01

    AF-GEOSpace Version 2.1 is a graphics-intensive software program with space environment models and applications developed recently by the Space Weather Center of Excellence at AFRL. A review of new and planned AF-GEOSpace capabilities will be given. The software addresses a wide range of physical domains and addresses such topics as solar disturbance propagation, geomagnetic field and radiation belt configurations, auroral particle precipitation, and ionospheric scintillation. Building on the success of previous releases, AF-GEOSpace has become a platform for the rapid prototyping of automated operational and simulation space weather visualization products and helps with a variety of tasks, including: orbit specification for radiation hazard avoidance; satellite design assessment and post-event anomaly analysis; solar disturbance effects forecasting; determination of link outage regions for active ionospheric conditions; satellite magnetic conjugate studies, scientific model validation and comparison, physics research, and education. Previously, Version 2.0 provided a simplified graphical user interface, improved science and application modules, significantly enhanced graphical performance, common input data archive sets, and 1-D, 2-D, and 3- D visualization tools for all models. Dynamic capabilities permit multiple environments to be generated at user- specified time intervals while animation tools enable the display of satellite orbits and environment data together as a function of time. Building on the Version 2.0 software architecture, AF-GEOSpace Version 2.1 includes a host of new modules providing, for example, plasma sheet charged particle fluxes, neutral atmosphere densities, 3-D cosmic ray cutoff maps, low-altitude trapped proton belt flux specification, DMSP particle data displays, satellite magnetic field footprint mapping determination, and meteor sky maps and shower/storm fluxes with spacecraft impact probabilities. AF-GEOSpace Version 2.1 was

  5. Screening Education And Recognition in Community pHarmacies of Atrial Fibrillation to prevent stroke in an ambulant population aged ≥65 years (SEARCH-AF stroke prevention study): a cross-sectional study protocol

    PubMed Central

    Freedman, Saul Benedict; Redfern, Julie; McLachlan, Andrew; Krass, Ines; Bennett, Alexandra; Briffa, Thomas; Bauman, Adrian; Neubeck, Lis

    2012-01-01

    Background Atrial fibrillation (AF) is associated with a high risk of stroke and may often be asymptomatic. AF is commonly undiagnosed until patients present with sequelae, such as heart failure and stroke. Stroke secondary to AF is highly preventable with the use of appropriate thromboprophylaxis. Therefore, early identification and appropriate evidence-based management of AF could lead to subsequent stroke prevention. This study aims to determine the feasibility and impact of a community pharmacy-based screening programme focused on identifying undiagnosed AF in people aged 65 years and older. Methods and analysis This cross-sectional study of community-based screening to identify undiagnosed AF will evaluate the feasibility of screening for AF using a pulse palpation and handheld single-lead electrocardiograph (ECG) device. 10 community pharmacies will be recruited and trained to implement the screening protocol, targeting a total of 1000 participants. The primary outcome is the proportion of people newly identified with AF at the completion of the screening programme. Secondary outcomes include level of agreement between the pharmacist's and the cardiologist's interpretation of the single-lead ECG; level of agreement between irregular rhythm identified with pulse palpation and with the single-lead ECG. Process outcomes related to sustainability of the screening programme beyond the trial setting, pharmacist knowledge of AF and rate of uptake of referral to full ECG evaluation and cardiology review will also be collected. Ethics and dissemination Primary ethics approval was received on 26 March 2012 from Sydney Local Health District Human Research Ethics Committee—Concord Repatriation General Hospital zone. Results will be disseminated via forums including, but not limited to, peer-reviewed publication and presentation at national and international conferences. Clinical trials registration number ACTRN12612000406808. PMID:22734120

  6. GPIM AF-M315E Propulsion System

    NASA Technical Reports Server (NTRS)

    Spores, Ronald A.; Masse, Robert; Kimbrel, Scott; McLean, Chris

    2014-01-01

    The NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) Technology Demonstration Mission (TDM) will demonstrate an operational AF-M315E green propellant propulsion system. Aerojet-Rocketdyne is responsible for the development of the propulsion system payload. This paper statuses the propulsion system module development, including thruster design and system design; Initial test results for the 1N engineering model thruster are presented. The culmination of this program will be high-performance, green AF-M315E propulsion system technology at TRL 7+, with components demonstrated to TRL 9, ready for direct infusion to a wide range of applications for the space user community.

  7. (U-Th)/He Apatite Age Data From the Inyo Mountains, California: Implications for the Timing of Extension and Dextral Slip Rates Along the Western Boundary of the Basin Range Province/Eastern California Shear Zone

    NASA Astrophysics Data System (ADS)

    Lee, J.; Stockli, D.

    2006-12-01

    With topographic relief of ~2.7 km, the Inyo Mountains, California is one of the largest mountains within the western part of the Basin Range Province (BRP) and Eastern California Shear Zone (ECSZ). This rugged range is underlain by Paleozoic sedimentary and metasedimentary rocks, Mesozoic plutons, and Quaternary alluvial deposits. An active, east-dipping normal fault, the eastern Inyo fault zone (EIFZ), defines the eastern flank of the range; the Saline Valley pull-apart basin is exposed in its hanging wall. To the south, the dextral Hunter Mountain fault (HMF) connects the EIFZ to the Panamint Valley fault. We completed the first (U-Th)/He apatite thermochronometric study on 24 samples collected from the Pat Keyes pluton across the range that bear on the timing of normal slip along the EIFZ and provide insight into the distribution of dextral shear across the ECSZ. Samples from the west-side of the range yield an elevation invariant (U-Th)/He age of 50.9±0.9 Ma. In contrast, samples from the east side of the range define two exhumed Partial Retention Zones (PRZ) and inflection points. From the top of the range ages systematically decrease from ~50 Ma at the top of the range to ~15 Ma. Below this upper inflection point, samples yield invariant (U-Th)/He ages of 15.0±0.3 Ma over a vertical distance of 0.8 km. (U-Th)/He ages then decrease again from ~15 Ma to ~3 Ma defining a Miocene-Pliocene PRZ. At the range front, below this lower inflection point, samples yield an invariant age of 2.8±0.1 Ma. We interpret these age patterns as indicating: (a) slow cooling (0.03- 0.06 mm/yr) through an older PRZ at high structural levels between >50 and 15.0 Ma; (b) rapid cooling, exhumation, and normal slip along the EIFZ at 15.0 Ma accommodated by westward tilting; (c) slow cooling (0.03-0.06 mm/yr) between 15.0 and 2.8 Ma through a younger PRZ; and (d) rapid cooling, exhumation, and renewed normal slip along the EIFZ at 2.8 Ma. The two episodes of exhumation along the EIFZ

  8. Molecular and functional identification of three interleukin-17A/F (IL-17A/F) homologues in large yellow croaker (Larimichthys crocea).

    PubMed

    Ding, Yang; Ao, Jingqun; Ai, Chunxiang; Chen, Xinhua

    2016-02-01

    The interleukin-17 (IL-17) cytokine family plays a central role in the coordination of inflammatory responses. In fish species, three genes that have a similar homology to both IL-17A and IL-17F were designated IL-17A/F1, 2, and 3. In this study, we identified three IL-17A/F homologues (LycIL-17A/F1, 2, and 3) from large yellow croaker (Larimichthys crocea). The deduced LycIL-17A/F1 and 3 had four cysteine residues conserved in teleost IL-17A/F1 and 3 homologues and shared a domain similar to the B chain of human IL-17F. The deduced LycIL-17A/F2 possessed the unique arrangement of six cysteine residues as teleost IL-17A/F2 (except Fugu IL-17A/F2) and higher vertebrate IL-17A and F, and shared a domain similar to the D/E chain of human IL-17A. Phylogenetic analysis showed that teleost IL-17A/F1 and 3 fall into a major clade, whereas IL-17A/F2 forms a separated clade and is clustered with IL-17N. Based on structural and phylogenetic analyses, we suggest that teleost IL-17A/Fs may be classified into two subgroups: one consisting of IL-17A/F1 and 3, and the other composed of IL-17A/F2. The three LycIL-17A/Fs were constitutively expressed in all tissues examined although at a different level. Following challenge with Aeromonas hydrophila, expression of these three LycIL-17A/Fs was rapidly increased in head kidney and gills. The in vivo assays showed that recombinant LycIL-17A/F1, 2, and 3 all were able to enhance the expression of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α2), chemokines (CXCL8 and CXCL13), and antimicrobial peptide hepcidin in head kidney. Furthermore, LycIL-17A/Fs appeared to mediate pro-inflammatory responses via NF-κB signalling. These results therefore reveal similar functions between the two subgroup members,LycIL-17A/F1 and 3 and LycIL-17A/F2, in promoting inflammation and host defences. PMID:26429410

  9. 33 CFR 3.05-15 - Sector Northern New England Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Sector Northern New England... England Marine Inspection Zone and Captain of the Port Zone. Sector Northern New England's office is located in Portland, ME. The boundaries of Sector Northern New England's Marine Inspection Zone...

  10. 33 CFR 3.05-10 - Sector Boston Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Sector Boston Marine Inspection... CAPTAIN OF THE PORT ZONES First Coast Guard District § 3.05-10 Sector Boston Marine Inspection Zone and Captain of the Port Zone. Sector Boston's office is located in Boston, MA. The boundaries of Sector...

  11. 33 CFR 3.35-40 - Sector Key West Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Sector Key West Marine Inspection... CAPTAIN OF THE PORT ZONES Seventh Coast Guard District § 3.35-40 Sector Key West Marine Inspection Zone and Captain of the Port Zone. Sector Key West's office is located in Key West, FL. The boundaries...

  12. 33 CFR 3.35-40 - Sector Key West Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Sector Key West Marine Inspection... CAPTAIN OF THE PORT ZONES Seventh Coast Guard District § 3.35-40 Sector Key West Marine Inspection Zone and Captain of the Port Zone. Sector Key West's office is located in Key West, FL. The boundaries...

  13. 33 CFR 3.35-40 - Sector Key West Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Sector Key West Marine Inspection... CAPTAIN OF THE PORT ZONES Seventh Coast Guard District § 3.35-40 Sector Key West Marine Inspection Zone and Captain of the Port Zone. Sector Key West's office is located in Key West, FL. The boundaries...

  14. 33 CFR 165.905 - USX Superfund Site Safety Zones: St. Louis River.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., within the designated boxes of latitude and longitude, are safety zones: (1) Safety Zone #1 (North Spirit...: 92°12′11″ W (2) Safety Zone #2 (South Spirit Lake): North Boundary: 46°40′45″ N South Boundary:...

  15. 33 CFR 165.905 - USX Superfund Site Safety Zones: St. Louis River.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., within the designated boxes of latitude and longitude, are safety zones: (1) Safety Zone #1 (North Spirit...: 92°12′11″ W (2) Safety Zone #2 (South Spirit Lake): North Boundary: 46°40′45″ N South Boundary:...

  16. Distinct binding determinants for 9-cis retinoic acid are located within AF-2 of retinoic acid receptor alpha.

    PubMed Central

    Tate, B F; Allenby, G; Janocha, R; Kazmer, S; Speck, J; Sturzenbecker, L J; Abarzúa, P; Levin, A A; Grippo, J F

    1994-01-01

    Retinoids exert their physiological action by interacting with two families of nuclear receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs), which regulate gene expression by forming transcriptionally active heterodimeric RAR/RXR or homodimeric RXR/RXR complexes on DNA. Retinoid receptor activity resides in several regions, including the DNA and ligand binding domains, a dimerization interface, and both a ligand-independent (AF-1) and a ligand-dependent (AF-2) transactivation function. While 9-cis retinoic acid (RA) alone is the cognate ligand for the RXRs, both 9-cis RA and all-trans RA (t-RA) compete for binding with high affinity to the RARs. This latter observation suggested to us that the two isomers may interact with a common binding site. Here we report that RAR alpha has two distinct but overlapping binding sites for 9-cis RA and t-RA. Truncation of a human RAR alpha to 419 amino acids yields a receptor that binds both t-RA and 9-cis RA with high affinity, but truncation to amino acid 404 yields a mutant receptor that binds only t-RA with high affinity. Remarkably, this region also defines a C-terminal boundary for AF-2, as addition of amino acids 405 to 419 restores receptor-mediated gene activity to a truncated human RAR alpha lacking this region. It is interesting to speculate that binding of retinoid stereoisomers to unique sites within an RAR may function with AF-2 to cause differential activation of retinoid-responsive gene pathways. Images PMID:8139538

  17. Boundary dynamics in landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Landscapes consist of a mosaic of distinct vegetation types and their intervening boundaries with distinct characteristics. Boundaries can exist along abrupt environmental gradients or along gradual changes that are reinforced by feedback mechanisms between plants and soil properties. Boundaries can...

  18. An Empirical Test of Oklahoma's A-F School Grades

    ERIC Educational Resources Information Center

    Adams, Curt M.; Forsyth, Patrick B.; Ware, Jordan; Mwavita, Mwarumba; Barnes, Laura L.; Khojasteb, Jam

    2016-01-01

    Oklahoma is one of 16 states electing to use an A-F letter grade as an indicator of school quality. On the surface, letter grades are an attractive policy instrument for school improvement; they are seemingly clear, simple, and easy to interpret. Evidence, however, on the use of letter grades as an instrument to rank and improve schools is scant…

  19. R2 AIRS/AFS FACILITY GIS LAYER

    EPA Science Inventory

    The AFS subsystem contains emissions, compliance, and permit data for stationary sources regulated by the U.S. EPA and state and local air pollution agencies. This information is used by states in preparation of State Implementation Plans (SIPs), to track the compliance status ...

  20. R2 AIRS/AFS PERMITS GIS LAYER

    EPA Science Inventory

    The Region 2 AIRS/AFS Permits Regulated Facility GIS layer contains identification (name, address, ID), and location (latitude, longitude, and locational metadata), attributes of stationary source(s) of air pollution associated with facilities that are regulated by the U. S. EPA....

  1. Treatment Guidelines of Atrial Fibrillation (AFib or AF)

    MedlinePlus

    ... Pressure Tools & Resources Stroke More Treatment Guidelines of Atrial Fibrillation (AFib or AF) Updated:Jun 23,2016 What ... content was last reviewed on 04/16/14. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters • ...

  2. Extracting uranium from seawater: Promising AF series adsorbents

    SciTech Connect

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8 ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.

  3. Extracting uranium from seawater: Promising AF series adsorbents

    DOE PAGESBeta

    Das, Sadananda; Oyola, Y.; Mayes, Richard T.; Janke, Christopher James; Kuo, Li-Jung; Gill, Gary; Wood, Jordana; Dai, Sheng

    2015-11-02

    Here, a new family of high surface area polyethylene fiber adsorbents (AF series) was recently developed at the Oak Ridge National Laboratory (ORNL). The AF series of were synthesized by radiation-induced graft polymerization of acrylonitrile and itaconic acid (at different monomer/co-monomer mol ratios) onto high surface area polyethylene fibers. The degree of grafting (%DOG) of AF series adsorbents was found to be 154 354%. The grafted nitrile groups were converted to amidoxime groups by treating with hydroxylamine. The amidoximated adsorbents were then conditioned with 0.44M KOH at 80 C followed by screening at ORNL with simulated seawater spiked with 8more » ppm uranium. Uranium adsorption capacity in simulated seawater screening ranged from 170-200 g-U/kg-ads irrespective of %DOG. A monomer/co-monomer mol ratio in the range of 7.57-10.14 seemed to be optimum for highest uranium loading capacity. Subsequently, the adsorbents were also tested with natural seawater at Pacific Northwest National Laboratory (PNNL) using flow-through exposure uptake experiments to determine uranium loading capacity with varying KOH conditioning time at 80 C. The highest adsorption capacity of AF1 measured after 56 days of marine testing was demonstrated as 3.9 g-U/kg-adsorbent and 3.2 g-U/kg-adsorbent for 1hr and 3hrs of KOH conditioning at 80 C, respectively. Based on capacity values of several AF1 samples, it was observed that changing KOH conditioning from 3hrs to 1hr at 80 C resulted in 22-27% increase in uranium loading capacity in seawater.« less

  4. 32 CFR 989.12 - AF Form 813, Request for Environmental Impact Analysis.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... record the focusing of environmental issues. ... 32 National Defense 6 2010-07-01 2010-07-01 false AF Form 813, Request for Environmental Impact... FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.12 AF Form...

  5. 32 CFR 989.12 - AF Form 813, Request for Environmental Impact Analysis.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... record the focusing of environmental issues. ... 32 National Defense 6 2011-07-01 2011-07-01 false AF Form 813, Request for Environmental Impact... FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.12 AF Form...

  6. 32 CFR 989.12 - AF Form 813, Request for Environmental Impact Analysis.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... record the focusing of environmental issues. ... 32 National Defense 6 2013-07-01 2013-07-01 false AF Form 813, Request for Environmental Impact... FORCE ENVIRONMENTAL PROTECTION ENVIRONMENTAL IMPACT ANALYSIS PROCESS (EIAP) § 989.12 AF Form...

  7. Destiny of earthward streaming plasma in the plasmasheet boundary layer

    NASA Technical Reports Server (NTRS)

    Green, J. L.; Horwitz, J. L.

    1986-01-01

    The dynamics of the earth's magnetotail have been investigated, and it has become clear that the plasmasheet boundary layer field lines map into the Region I Field-Aligned Currents (FAC) of the auroral zone. It is pointed out that the role of earthward streaming ions in the plasmasheet boundary layer may be of fundamental importance in the understanding of magnetotail dynamics, auroral zone physics, and especially for ionospheric-magnetospheric interactions. The present paper has the objective to evaluate propagation characteristics for the earthward streaming ions observed in the plasmasheet boundary layer. An investigation is conducted of the propagation characteristics of protons in the plasmasheet boundary layer using independent single particle dynamics, and conclusions are discussed. The density of earthward streaming ions found in the plasmasheet boundary layer should include the ring current as well as the auroral zone precipitaiton and inner plasmasheet regions of the magnetosphere.

  8. 15 CFR 922.101 - Boundary.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... high water line from this intersection point at the southern tip of Ma'ama'a Cove to the intersection... the southern tip of Ma'ama'a Cove Point. The landward boundary of Zone B is defined by the mean high high water line from this intersection point at the southern tip of Ma'ama'a Cove around the...

  9. Seismic structure of the Costa Rican subduction system from active-source onshore-offshore seismic data and imaging plate boundary processes at the Cascadia subduction zone offshore Washington

    NASA Astrophysics Data System (ADS)

    Everson, Erik D.

    The goal of this thesis is to use seismic methods, either wide-angle refraction or multi-channel seismic (MCS) reflection, to characterize the physical processes occurring at the subduction zones occurring offshore Costa Rica and Cascadia. The first two chapters use wide-angle refraction data to characterize lithospheric structure and velocities, based on the modeling of wide-angle refractions and reflections from the crust, Moho and upper mantle. They also use MCS data to characterize the uppermost structure that wide-angle refraction data alone cannot provide. The first chapter uses both wide-angle refraction and MCS data to address the hypothesis that bending-related normal faulting, clearly imaged in the MCS data, provides a pathway for seawater to percolate down into the uppermost mantle and serpentinize it. This process causes a reduction in the seismic p-wave velocity in the upper mantle, which can be detected by wide-angle refraction analysis. We found the upper 1-2 km of the mantle has reduced velocities of 7.5 - 7.6 km/s in the area of pervasive normal faulting within the CNS-2 segment, and regular upper mantle velocities of 8.0 - 8.2 km/s in the CNS-1 segment, which lacks pervasive normal faulting. Our results suggest a link between bending-related large-offset normal faults seen in bathymetric and MCS reflection data in subduction trenches and serpentinization of the upper mantle. The second chapter uses both wide-angle refraction and MCS data like the first chapter but addresses the hypothesis that juvenile continental crust is created at some volcanic arcs. We addressed this hypothesis by creating a lithospheric velocity and structural model for the Central American subduction system through Costa Rica. This model allows us to estimate the seismic velocity, structure, infer bulk composition (from seismic velocities), and estimate a magmatic flux rate for the volcanic arc. We found a total crustal thickness of ~44 km and mid-to-lower-crustal velocities

  10. Embossed Teflon AF Laminate Membrane Microfluidic Diaphragm Valves

    NASA Technical Reports Server (NTRS)

    Willis, Peter; Hunt, Brian; White,Victor; Grunthaner, Frank

    2008-01-01

    A microfluidic system has been designed to survive spaceflight and to function autonomously on the Martian surface. It manipulates microscopic quantities of liquid water and performs chemical analyses on these samples to assay for the presence of molecules associated with past or present living processes. This technology lies at the core of the Urey Instrument, which is scheduled for inclusion on the Pasteur Payload of the ESA ExoMars rover mission in 2013. Fabrication processes have been developed to make the microfabricated Teflon-AF microfluidic diaphragm pumps capable of surviving extreme temperature excursions before and after exposure to liquid water. Two glass wafers are etched with features and a continuous Teflon membrane is sandwiched between them (see figure). Single valves are constructed using this geometry. The microfabricated devices are then post processed by heating the assembled device while applying pneumatic pressure to force the Teflon diaphragm against the valve seat while it is softened. After cooling the device, the embossed membrane retains this new shape. This solves previous problems with bubble introduction into the fluid flow where deformations of the membrane at the valve seat occurred during device bonding at elevated temperatures (100-150 C). The use of laminated membranes containing commercial Teflon AF 2400 sheet sandwiched between spun Teflon AF 1600 layers performed best, and were less gas permeable than Teflon AF 1600 membranes on their own. Spinning Teflon AF 1600 solution (6 percent in FLOURINERT(Registered TradeMark) FC40 solvent, 3M Company) at 500 rpm for 1.5 seconds, followed by 1,000 rpm for 3 seconds onto Borofloat glass wafers, results in a 10-micron-thick film of extremely smooth Teflon AF. This spinning process is repeated several times on flat, blank, glass wafers in order to gradually build a thick, smooth membrane. After running this process at least five times, the wafer and Teflon coating are heated under vacuum

  11. Characterization of physically vapor deposited AF2400 thin films

    SciTech Connect

    Chow, R.; Spragge, M.K.; Loomis, G.E.; Rainer, F.; Ward, R.; Thomas, I.M.; Kozlowski, M.R.

    1993-11-01

    Anti-reflective coatings made with Teflon AF2400 had the highest damage thresholds recorded for physical vapor deposited coatings at the Lawrence Livermore National Laboratory damage facility. Physical vapor deposited layers of Teflon AF2400, a perfluorinated amorphous polymer, maintained the bulk optical properties of a high transmittance from 200 nm to 1600 nm, and a low refractive index. In addition, the refractive index can be intentionally reduced by control of two common deposition parameters, deposition rate and substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions.

  12. Sinuladiterpenes A-F, new cembrane diterpenes from Sinularia flexibilis.

    PubMed

    Lo, Kuang-Liang; Khalil, Ashraf Taha; Kuo, Yao-Haur; Shen, Ya-Ching

    2009-12-01

    Chromatographic investigation of the octocoral Sinularia flexibilis afforded six new cembrane diterpenes, sinuladiterpenes A-F (1-6, resp.), in addition to four known cembranolides, 11-episinulariolide acetate, 11-dehydrosinulariolide, 11-episinulariolide, and sinulariolide. Their structures were elucidated by spectroscopic analysis, especially 2D-NMR and HR-ESI-MS. Compound 2 exhibited significant in vitro cytotoxic activity against human colon adenocarcinoma (WiDr) cell line. PMID:20020460

  13. Reactive Flow Calculation near a Free Boundary.

    NASA Astrophysics Data System (ADS)

    Partom, Yehuda

    2007-06-01

    In reactive flow calculations of detonation in a rod, an unreacted layer is formed at the boundary, affecting the diameter effect outcome. We investigate the origin of this boundary layer, and propose a simple and practical way to eliminate it. We show that it is an artifact of the finite rise time of the shock, caused by artificial viscosity. When the shock reaches a boundary cell, it releases right away, so that pressure and temperature there only reach a fraction of their shock levels, and the reaction rate is slow. We propose to remedy this artifact by delaying the boundary motion for a short while (40 nsec for a 10 cells per mm mesh) after arrival of the shock. In this way the boundary cells reach the appropriate pressure and temperature and react at the appropriate rate. In the paper we show how this remedy works. We compute detonation in a rod with different values of the boundary motion delay, compare the breakout curve from the far end with data from the literature, and obtain good agreement. This finite rise time effect near a low impedance boundary plays a role also in calculations of corner turning situations. But there the detonation borders with a dead zone, and the boundary contour is not known in advance.

  14. Reactive Flow Calculation Near a Free Boundary

    NASA Astrophysics Data System (ADS)

    Partom, Yehuda

    2007-12-01

    In reactive flow calculations of detonation in a rod, an unreacted or slow reacting layer is formed at the boundary, affecting the diameter effect outcome. We investigate the origin of this boundary layer, and propose a simple and practical way to eliminate it. We show that it is an artifact of the finite rise time of the shock, caused by artificial viscosity. When the shock reaches a boundary cell, it is released right away, so that pressure and temperature there only reach a fraction of their shock levels, and the reaction rate is slow. We propose to remedy this artifact by delaying the boundary motion for a short while (about 40 ns for a 10 cells per mm mesh) after arrival of the shock. In this way boundary cells can reach the appropriate pressure and temperature and react at the appropriate rate. In the paper we show how this remedy works. We compute detonation in a rod with different values of the boundary motion delay, compare the breakout curve from the far end with data from the literature, and obtain good agreement. This finite rise time effect near a low impedance boundary plays a role also in calculations of corner turning situations. But there the detonation borders with a dead zone, and the boundary contour is not known in advance.

  15. Durable Superhydrophobic Surfaces via Spontaneous Wrinkling of Teflon AF.

    PubMed

    Scarratt, Liam R J; Hoatson, Ben S; Wood, Elliot S; Hawkett, Brian S; Neto, Chiara

    2016-03-16

    We report the fabrication of both single-scale and hierarchical superhydrophobic surfaces, created by exploiting the spontaneous wrinkling of a rigid Teflon AF film on two types of shrinkable plastic substrates. Sub-100 nm to micrometric wrinkles were reproducibly generated by this simple process, with remarkable control over the size and hierarchy. Hierarchical Teflon AF wrinkled surfaces showed extremely high water repellence (contact angle 172°) and very low contact angle hysteresis (2°), resulting in droplets rolling off the surface at tilt angles lower than 5°. The wrinkling process intimately binds the Teflon AF layer with its substrate, making these surfaces mechanically robust, as revealed by macroscale and nanoscale wear tests: hardness values were close to that of commercial optical lenses and aluminum films, resistance to scratch was comparable to commercial hydrophobic coatings, and damage by extensive sonication did not significantly affect water repellence. By this fabrication method the size of the wrinkles can be reproducibly tuned from the nanoscale to the microscale, across the whole surface in one step; the fabrication procedure is extremely rapid, requiring only 2 min of thermal annealing to produce the desired topography, and uses inexpensive materials. The very low roll-off angles achieved in the hierarchical surfaces offer a potentially up-scalable alternative as self-cleaning and drag-reducing coatings. PMID:26910574

  16. Genomic functions of U2AF in constitutive and regulated splicing

    PubMed Central

    Wu, Tongbin; Fu, Xiang-Dong

    2015-01-01

    The U2AF heterodimer is generally accepted to play a vital role in defining functional 3′ splice sites in pre-mRNA splicing. Given prevalent mutations in U2AF, particularly in the U2AF1 gene (which encodes for the U2AF35 subunit) in blood disorders and other human cancers, there are renewed interests in these classic splicing factors to further understand their regulatory functions in RNA metabolism in both physiological and disease settings. We recently reported that U2AF has a maximal capacity to directly bind ˜88% of functional 3′ splice sites in the human genome and that numerous U2AF binding events also occur in various exonic and intronic locations, thus providing additional mechanisms for the regulation of alternative splicing besides their traditional role in titrating weak splice sites in the cell. These findings, coupled with the existence of multiple related proteins to both U2AF65 and U2AF35, beg a series of questions on the universal role of U2AF in functional 3′ splice site definition, their binding specificities in vivo, potential mechanisms to bypass their requirement for certain intron removal events, contribution of splicing-independent functions of U2AF to important cellular functions, and the mechanism for U2AF mutations to invoke specific diseases in humans. PMID:25901584

  17. Identification and functional characterization of grass carp IL-17A/F1: An evaluation of the immunoregulatory role of teleost IL-17A/F1.

    PubMed

    Du, Linyong; Feng, Shiyu; Yin, Licheng; Wang, Xinyan; Zhang, Anying; Yang, Kun; Zhou, Hong

    2015-07-01

    In mammals, IL-17A and IL-17F are hallmark cytokines of Th17 cells which act significant roles in eradicating extracellular pathogens. IL-17A and IL-17F homologs nominated as IL-17A/F1-3 have been revealed in fish and their functions remain largely undefined. Here we identified and characterized grass carp IL-17A/F1 (gcIL-17A/F1) in fish immune system. In this regard, both tissue distribution and inductive expression of gcIL-17A/F1 indicated its possible involvement in immune response. Moreover, recombinant gcIL-17A/F1 (rgcIL-17A/F1) was prepared and displayed an ability to enhance pro-inflammatory cytokines (IL-1β, TNF-α and IL-6) mRNA expression in head kidney leukocytes. It is suggestive of that gcIL-17A/F1 may act as a proinflammatory cytokine in fish immunity. Besides, rgcIL-17A/F1 induced gene expression and protein release of grass carp chemokine CXCL-8 (gcCXCL-8) in head kidney cells (HKCs), probably via NF-κB, p38 and Erk1/2 pathways. In particular, culture medium from the HKCs treated by rgcIL-17A/F1 could stimulate peripheral blood leukocytes migration and immunoneutralization of endogenous gcCXCL-8 could partially attenuate this stimulation, suggesting that rgcIL-17A/F1 could recruit immune cells through producing gcCXCL-8 as mammalian IL-17 A and F. Taken together, we not only identified the pro-inflammatory role of gcIL-17A/F1 in host defense, but also provided the basis for clarifying Th17 cells in teleost. PMID:25847875

  18. Determination of Boundary Scattering, Intermagnon Scattering, and the Haldane Gap in Heisenberg Chains

    NASA Astrophysics Data System (ADS)

    Ueda, Hiroshi; Kusakabe, Koichi

    2012-02-01

    Low-lying magnon dispersion in a S=1 Heisenberg antiferromagnetic (AF) chain with boundary S/2 spins coupling antiferromagnetically (Jend> 0) is analyzed by use of the non-Abelian DMRG method. The Haldane gap δ, the magnon velocity v, the inter-magnon scattering length a, and the scattering length ab of the boundary coupling are evaluated. The length ab, which represents the contribution of boundary effects, depends on Jend drastically, while δ, v, and a are constant irrespective of Jend. Our method estimates the gap of the S=2 AF chain as δ= 0.0891623(9) using a chain length up to 2048, which is longer than the correlation length.

  19. Variations in the kinematics of deformation along the Zagros inclined transpression zone, Iran: Implications for defining a curved inclined transpression zone

    NASA Astrophysics Data System (ADS)

    Sarkarinejad, Khalil; Partabian, Abdolreza; Faghih, Ali

    2013-03-01

    The combination of inclined collision and plate boundary shape can control the nature of deformation and the sense of shear along a transpression zone. The present study investigated the effects of a boundary zone with curvilinear shape along a transpression zone on the kinematics of deformation. The kinematics of the Zagros transpression zone varies with the orientation of the zone boundary. Detailed structural and microstructural studies showed sinistral sense of shear on the southeastern part of the Zagros inclined transpression zone (Fars Arc), but dextral sense of shear on the northwestern part of the zone. It is inferred that the both senses of shear were developed coevally under a bulk general shear, regional-scale deformation along a curved inclined transpression miming the shape of the Fras Arc of the Zagros and the reentrant of the Bandar Abbas Syntaxis. The Zagros transpression zone formed by inclined continental collision between the Afro-Arabian continent and Iranian microcontinent.

  20. Boundary-element shape sensitivity analysis for thermal problems with nonlinear boundary conditions

    NASA Technical Reports Server (NTRS)

    Kane, James H.; Wang, Hua

    1991-01-01

    Implicit differentiation of the discretized boundary integral equations governing the conduction of heat in solid objects subjected to nonlinear boundary conditions is shown to generate an accurate and economical approach for the computation of shape sensitivities for this class of problems. This approach involves the employment of analytical derivatives of boundary-element kernel functions with respect to shape design variables. A formulation is presented that can consistently account for both temperature-dependent convection and radiation boundary conditions. Several iterative strategies are presented for the solution of the resulting sets of nonlinear equations and the computational performances examined in detail. Multizone analysis and zone condensation strategies are demonstrated to provide substantive computational economies in this process for models with either localized nonlinear boundary conditions or regions of geometric insensitivity to design variables. A series of nonlinear example problems are presented that have closed-form solutions.

  1. NATIONAL FOREST BOUNDARIES

    EPA Science Inventory

    This dataset contains National Forest boundaries for the lower 48 states, including Puerto Rico. Alaska is maintained separately. This dataset includes administrative unit boundaries, derived primarily from the GSTC SOC data system, comprised of Cartographic Feature Files (CFFs...

  2. A conservative treatment of zonal boundaries for Euler equation calculations

    NASA Technical Reports Server (NTRS)

    Rai, M. M.

    1984-01-01

    Finite-difference calculations require the generation of a grid for the region of interest. A zonal approach, wherein the given region is subdivided into zones and the grid for each zone is generated independently, makes the grid-generation process for complicated topologies and for regions requiring selective grid refinement a fairly simple task. This approach results in new boundaries within the given region, that is, zonal boundaries at the interfaces of the various zones. The zonal-boundary scheme (the integration scheme used to update the points on the zonal boundary) for the Euler equations must be conservative, accurate, stable, and applicable to general curvilinear coordinate systems. A zonal-boundary scheme with these desirable properties is developed in this study. The scheme is designed for explicit, first-order-accurate integration schemes but can be modified to accommodate second-order-accurate explicit and implicit integration schemes. Results for inviscid flow, including supersonic flow over a cylinder, blast-wave diffraction by a ramp, and one-dimensional shock-tube flow are obtained on zonal grids. The conservative nature of the zonal-boundary scheme permits the smooth transition of the discontinuities associated with these flows from one zone to another. The calculations also demonstrate the continuity of contour lines across zonal boundaries that can be achieved with the present zonal scheme.

  3. A Conservation Treatment of Zonal Boundaries for Euler Equation Calculations

    NASA Technical Reports Server (NTRS)

    Rai, Man Mohan

    1986-01-01

    Finite-difference calculations require the generation of a grid for the region of interest. A zonal approach, wherein the given region is subdivided into zones and the grid for each zone is generated independently, makes the grid-generation process for complicated topologies and for regions requiring selective grid refinement a fairly simple task. This approach results in new boundaries within the given region, that is, zonal boundaries at the interfaces of the various zones. The zonal-boundary scheme (the integration scheme used to update the points on the zonal boundary) for the Euler equations must be conservative, accurate, stable, and applicable to general curvilinear coordinate systems. A zonal-boundary scheme with these desirable properties is developed in this study. The scheme is designed for explicit, first-order-accurate integration schemes but can be modified to accommodate second-order-accurate explicit and implicit integration schemes. Results for inviscid flow, including supersonic flow over a cylinder, blast-wave diffraction by a ramp, and one-dimensional shock-tube flow are obtained on zonal grids. The conservative nature of the zonal-boundary scheme permits the smooth transition of the discontinuities associated with these flows from one zone to another. The calculations also demonstrate the continuity of contour lines across zonal boundaries that can be achieved with the present zonal scheme.

  4. Doppler images and the underlying dynamo. The case of AF Leporis

    NASA Astrophysics Data System (ADS)

    Järvinen, S. P.; Arlt, R.; Hackman, T.; Marsden, S. C.; Küker, M.; Ilyin, I. V.; Berdyugina, S. V.; Strassmeier, K. G.; Waite, I. A.

    2015-02-01

    Context. The (Zeeman-)Doppler imaging studies of solar-type stars very often reveal large high-latitude spots. This also includes F stars that possess relatively shallow convection zones, indicating that the dynamo operating in these stars differs from the solar dynamo. Aims: We aim to determine whether mean-field dynamo models of late-F type dwarf stars can reproduce the surface features recovered in Doppler maps. In particular, we wish to test whether the models can reproduce the high-latitude spots observed on some F dwarfs. Methods: The photometric inversions and the surface temperature maps of AF Lep were obtained using the Occamian-approach inversion technique. Low signal-to-noise spectroscopic data were improved by applying the least-squares deconvolution method. The locations of strong magnetic flux in the stellar tachocline as well as the surface fields obtained from mean-field dynamo solutions were compared with the observed surface temperature maps. Results: The photometric record of AF Lep reveals both long- and short-term variability. However, the current data set is too short for cycle-length estimates. From the photometry, we have determined the rotation period of the star to be 0.9660 ± 0.0023 days. The surface temperature maps show a dominant, but evolving, high-latitude (around +65°) spot. Detailed study of the photometry reveals that sometimes the spot coverage varies only marginally over a long time, and at other times it varies rapidly. Of a suite of dynamo models, the model with a radiative interior rotating as fast as the convection zone at the equator delivered the highest compatibility with the obtained Doppler images. Partially based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofísica de Canarias.Based partly on STELLA SES data.Tables 1-3 and Figs. 7-14 are available in

  5. Why subduction zones are curved

    NASA Astrophysics Data System (ADS)

    Mahadevan, L.; Bendick, R.; Liang, Haiyi

    2010-12-01

    We give an explanation for the polarity, localization, shape, size, and initiation of subduction zones on Earth. By considering a soft, thin, curved lithospheric cap with either elastic or viscous rheology supported by a thick, nearly incompressible mantle, we find two different characteristic subduction geometries arise depending on boundary conditions: (1) plate boundaries where subduction results primarily from the gravitational body force (free subduction) have characteristic plate lengths and form arc-shaped dimpled segments resulting from the competition between bending and stretching in edge buckling modes of thin spherical shells, and (2) subduction zones due to localized applied loads that push one slab of thin, positively buoyant lithosphere beneath an overriding plate (forced subduction) form localized straight segments, consistent with the deformation of indented spherical shells. Both types of subduction are nonlinear subcritical instabilities, so small perturbations in the mechanical properties of the lithosphere have pronounced effects on subduction initiation and evolution. Yet in both cases, geometric relationships determined by the shape of the Earth itself play the most critical role in controlling the basic morphology and characteristic length scales of subduction zones.

  6. Numerical Boundary Condition Procedures

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Topics include numerical procedures for treating inflow and outflow boundaries, steady and unsteady discontinuous surfaces, far field boundaries, and multiblock grids. In addition, the effects of numerical boundary approximations on stability, accuracy, and convergence rate of the numerical solution are discussed.

  7. On boundary superalgebras

    SciTech Connect

    Doikou, Anastasia

    2010-04-15

    We examine the symmetry breaking of superalgebras due to the presence of appropriate integrable boundary conditions. We investigate the boundary breaking symmetry associated with both reflection algebras and twisted super-Yangians. We extract the generators of the resulting boundary symmetry as well as we provide explicit expressions of the associated Casimir operators.

  8. Binding sites for two novel phosphoproteins, 3AF5 and 3AF3, are required for rbcS-3A expression.

    PubMed Central

    Sarokin, L P; Chua, N H

    1992-01-01

    Previous studies of boxes II (-151 to -138) and III (-125 to -114), binding sites for the nuclear factor GT-1 within the -166 deleted promoter of the ribulose-1,5-bisphosphate carboxylase-3A (rbcS-3A) gene, suggested that GT-1 might act in concert with an additional protein to confer light-responsive rbcS-3A expression. In this work, S1 analysis of RNA isolated from transgenic tobacco plants carrying mutant rbcS-3A constructs led to the identification of two short sequences located at the 5' and 3' ends of box III that are required for expression. These two sequences serve as binding sites for two novel proteins, 3AF5 and 3AF3. Gel shift studies using tetramerized binding sites for both 3AF5 and 3AF3 showed that complexes with faster mobilities were formed using nuclear extracts prepared from dark-adapted plants compared with those from light-grown tobacco plants. Phosphatase treatment of extracts from light-grown plants resulted in the formation of complexes with faster mobility. Although the binding of 3AF3 to its target site is dependent upon phosphorylation, the binding of 3AF5 does not appear to be affected by its phosphorylation state. These results suggest that the phosphorylated forms of both 3AF5 and 3AF3 are required for -166 rbcS-3A expression but that the mechanisms differ by which phosphorylation regulates the activities of 3AF5 and 3AF3. PMID:1498605

  9. Free-Stream Boundaries of Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Corrsin, Stanley; Kistler, Alan L

    1955-01-01

    Report presents the results of an experimental and theoretical study made of the instantaneously sharp and irregular front which is always found to separate turbulent fluid from contiguous "nonturbulent" fluid at a free-stream boundary. This distinct demarcation is known to give an intermittent character to hot-wire signals in the boundary zone. The overall behavior of the front is described statistically in terms of its wrinkle-amplitude growth and its lateral propagation relative to the fluid as functions of downstream coordinate.

  10. The Advancing State of AF-M315E Technology

    NASA Technical Reports Server (NTRS)

    Masse, Robert; Spores, Ronald A.; McLean, Chris

    2014-01-01

    The culmination of twenty years of applied research in hydroxyl ammonium nitrate (HAN)-based monopropellants, the NASA Space Technology mission Directorate's (STMD) Green Propellant Infusion Mission (GPIM) will achieve the first on-orbit demonstration of an operational AF-M315E green propellant propulsion system by the end of 2015. Following an contextual overview of the completed flight design of the GPIM propellant storage and feed system, results of first operation of a flight-representative heavyweight 20-N engineering model thruster (to be conducted in mid-2014) are presented with performance comparisons to prior lab model (heavyweight) test articles.

  11. RX-26-AY/AF rifle bullet tests

    SciTech Connect

    Sharp, D.D.

    1980-11-01

    A series of rifle bullet tests was performed on two explosives, RX-26-AY and RX-26-AF, using the Pantex version of the Picatinny Arsenal Test (PA-2). With the exception of one test, both explosives displayed a relatively low sensitivity to bullet impact. However, a marked difference was noted in the average burn time duration between the two types of explosives being tested. A minor modification was made on the rifle barrel used at the test site in order to improve the sighting procedure.

  12. Zone separator for multiple zone vessels

    DOEpatents

    Jones, John B.

    1983-02-01

    A solids-gas contact vessel, having two vertically disposed distinct reaction zones, includes a dynamic seal passing solids from an upper to a lower zone and maintaining a gas seal against the transfer of the separate treating gases from one zone to the other, and including a stream of sealing fluid at the seal.

  13. Remote sensing of the marginal ice zone during Marginal Ice Zone Experiment (MIZEX) 83

    NASA Technical Reports Server (NTRS)

    Shuchman, R. A.; Campbell, W. J.; Burns, B. A.; Ellingsen, E.; Farrelly, B. A.; Gloersen, P.; Grenfell, T. C.; Hollinger, J.; Horn, D.; Johannessen, J. A.

    1984-01-01

    The remote sensing techniques utilized in the Marginal Ice Zone Experiment (MIZEX) to study the physical characteristics and geophysical processes of the Fram Strait Region of the Greenland Sea are described. The studies, which utilized satellites, aircraft, helicopters, and ship and ground-based remote sensors, focused on the use of microwave remote sensors. Results indicate that remote sensors can provide marginal ice zone characteristics which include ice edge and ice boundary locations, ice types and concentration, ice deformation, ice kinematics, gravity waves and swell (in the water and the ice), location of internal wave fields, location of eddies and current boundaries, surface currents and sea surface winds.

  14. NMR study of the AF-SC-SC-AF phased transition in a pnictide superconductor LaFeAsO1-xHx

    NASA Astrophysics Data System (ADS)

    Fujiwara, Naoki; Sakurai, Ryosuke; Iimura, Soushi; Matsuishi, Satoru; Hosono, Hideo; Yamakawa, Youichi; Kontani, Hiroshi

    2014-03-01

    We have performed 75As and 1H NMR measurements in LaFeAsO1xHx, an isomorphic compound of LaFeAsO1xFx. LaFeAsO1xHx is an electron doped system, and O2- can be replaced with H- up to x = 0.5. LaFeAsO1xHx is known for having double superconducting (SC) domes on H doping. Recently, we discovered that a new antiferromagnetic (AF) phase follows the double SC domes on further H doping, forming a symmetric AF-SC-SC-AF phase alignment in the electronic phase diagram Unlike the AF ordering in the lightly H-doped regime, the AF ordering in the highly H-doped regime is attributed to the nesting between electron pockets. In the conference, we will show the data of both NMR spectra and the relaxation rate 1/T1 in the whole doping region. We will discuss the difference of electronic states between the lightly H-doped AF-SC phases and highly H-doped SC-AF phases. This work is supported by a Grant-in-Aid (Grant No. KAKENHI 23340101) from the Ministry of Education, Science, and Culture, Japan.

  15. Beyond the classic thermoneutral zone

    PubMed Central

    Kingma, Boris RM; Frijns, Arjan JH; Schellen, Lisje; van Marken Lichtenbelt, Wouter D

    2014-01-01

    The thermoneutral zone is defined as the range of ambient temperatures where the body can maintain its core temperature solely through regulating dry heat loss, i.e., skin blood flow. A living body can only maintain its core temperature when heat production and heat loss are balanced. That means that heat transport from body core to skin must equal heat transport from skin to the environment. This study focuses on what combinations of core and skin temperature satisfy the biophysical requirements of being in the thermoneutral zone for humans. Moreover, consequences are considered of changes in insulation and adding restrictions such as thermal comfort (i.e. driver for thermal behavior). A biophysical model was developed that calculates heat transport within a body, taking into account metabolic heat production, tissue insulation, and heat distribution by blood flow and equates that to heat loss to the environment, considering skin temperature, ambient temperature and other physical parameters. The biophysical analysis shows that the steady-state ambient temperature range associated with the thermoneutral zone does not guarantee that the body is in thermal balance at basal metabolic rate per se. Instead, depending on the combination of core temperature, mean skin temperature and ambient temperature, the body may require significant increases in heat production or heat loss to maintain stable core temperature. Therefore, the definition of the thermoneutral zone might need to be reformulated. Furthermore, after adding restrictions on skin temperature for thermal comfort, the ambient temperature range associated with thermal comfort is smaller than the thermoneutral zone. This, assuming animals seek thermal comfort, suggests that thermal behavior may be initiated already before the boundaries of the thermoneutral zone are reached. PMID:27583296

  16. AFS men and women differ most in their lifestyle choices

    USGS Publications Warehouse

    Connelly, N.A.; Brown, T.L.; Hardiman, J.M.

    2006-01-01

    The American Fisheries Society sponsored a survey to examine the career development choices of men and women and how they might differ by gender. A random sample of 700 men and 700 women was selected from the AFS membership database. The survey was mailed out in October 2004 and 991 questionnaires were returned for an adjusted response rate of 71%. Some differences exist between men and women in the areas of interest development, education, and employment, but the substantive differences occur in lifestyle choices. Women with a fisheries career are less likely to be married than men, even when age is controlled for, and women who are married are more likely to have dual-career considerations than their male counterparts. Among respondents without dependents in their home during their professional career, twice as many women as men think having children will adversely affect their career. For those with dependents, more than twice as many women as men said they had to put their career "on hold" because of their dependents. While AFS members do not represent all members of the fisheries profession, their experiences shed substantial light on the lifestyle choices likely faced by most members of the profession.

  17. Chemically peculiar A/F stars in open clusters of the Milky Way

    NASA Astrophysics Data System (ADS)

    Gebran, M.; Monier, R.

    2010-12-01

    Abundance anomalies have been determined at the surface of many field and open cluster A and F dwarfs. These abundance anomalies are most likely caused by microscopic diffusion at work within the stable envelopes of A stars. However diffusion can be counteracted by several other mixing processes such as convection, rotational mixing and mass loss. We present a short review of the surface abundance patterns of A/F stars in the Pleiades (100 Myr), Coma Berenices (450 Myr) and Hyades (650 Myr) open clusters. Real star-to-star variations of the abundances were found for several chemical elements in the A dwarfs in these clusters. The derived abundances are then compared to evolutionary models from the Montreal group. These comparisons strongly suggest the occurence of hydrodynamical processes at play within the radiative zones of these stars and hindering the effects of microscopic diffusion (mixing processes/mass loss). In the frame of Gaia mission, simulations are presented that predict the number of A stars and open clusters that Gaia will observe in the Galaxy.

  18. Identification and characterization of the afsR homologue regulatory gene from Streptomyces peucetius ATCC 27952.

    PubMed

    Parajuli, Niranjan; Viet, Hung Trinh; Ishida, Kenji; Tong, Hang Thi; Lee, Hei Chan; Liou, Kwangkyoung; Sohng, Jae Kyung

    2005-01-01

    We have isolated an afsR homologue, called afsR-p, through genome analysis of Streptomyces peucetius ATCC 27952. AfsR-p shares 60% sequence identity with AfsR from Streptomyces coelicolor A3 (2). afsR-p was expressed under the control of the ermE* promoter in its hosts S. peucetius, Streptomyces lividans TK 24, Streptomyces clavuligerus and Streptomyces griseus. We observed overproduction of doxorubicin (4-fold) in S. peucetius, gamma-actinorhodin (2.6-fold) in S. lividans, clavulanic acid (1.5-fold) in S. clavuligerus and streptomycin (slight) in S. griseus. Overproduction was due to expression of the gene in these strains as compared to the wild-type strains harboring the vector only. Comparative study of the expression of afsR-p revealed that regulatory networking in Streptomyces is not uniform. We speculate that phosphorylated AfsR-p becomes bound to the promoter region of afsS. The latter activates other regulatory genes, including pathway regulatory genes, and induces the production of secondary metabolites including antibiotics. We identified specific conserved amino acids and exploited them for the isolation of the partial sequence of the afsR homologue from S. clavuligerus and Streptomyces achromogens (rubradirin producer). Such findings provide additional evidence for the presence of a serine/threonine and tyrosine kinase-dependent global regulatory network in Streptomyces. PMID:15921897

  19. Dual Function for U2AF35 in AG-Dependent Pre-mRNA Splicing

    PubMed Central

    Guth, Sabine; Tange, Thomas O/.; Kellenberger, Esther; Valcárcel, Juan

    2001-01-01

    The splicing factor U2AF is required for the recruitment of U2 small nuclear RNP to pre-mRNAs in higher eukaryotes. The 65-kDa subunit of U2AF (U2AF65) binds to the polypyrimidine (Py) tract preceding the 3′ splice site, while the 35-kDa subunit (U2AF35) contacts the conserved AG dinucleotide at the 3′ end of the intron. It has been shown that the interaction between U2AF35 and the 3′ splice site AG can stabilize U2AF65 binding to weak Py tracts characteristic of so-called AG-dependent pre-mRNAs. U2AF35 has also been implicated in arginine-serine (RS) domain-mediated bridging interactions with splicing factors of the SR protein family bound to exonic splicing enhancers (ESE), and these interactions can also stabilize U2AF65 binding. Complementation of the splicing activity of nuclear extracts depleted of U2AF by chromatography in oligo(dT)-cellulose requires, for some pre-mRNAs, only the presence of U2AF65. In contrast, splicing of a mouse immunoglobulin M (IgM) M1-M2 pre-mRNA requires both U2AF subunits. In this report we have investigated the sequence elements (e.g., Py tract strength, 3′ splice site AG, ESE) responsible for the U2AF35 dependence of IgM. The results indicate that (i) the IgM substrate is an AG-dependent pre-mRNA, (ii) U2AF35 dependence correlates with AG dependence, and (iii) the identity of the first nucleotide of exon 2 is important for U2AF35 function. In contrast, RS domain-mediated interactions with SR proteins bound to the ESE appear to be dispensable, because the purine-rich ESE present in exon M2 is not essential for U2AF35 activity and because a truncation mutant of U2AF35 consisting only of the pseudo-RNA recognition motif domain and lacking the RS domain is active in our complementation assays. While some of the effects of U2AF35 can be explained in terms of enhanced U2AF65 binding, other activities of U2AF35 do not correlate with increased cross-linking of U2AF65 to the Py tract. Collectively, the results argue that

  20. 33 CFR 3.40-40 - Sector Upper Mississippi River Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Sector Upper Mississippi River... Mississippi River Marine Inspection Zone and Captain of the Port Zone. Sector Upper Mississippi River's office is located in St. Louis, MO. The boundaries of Sector Upper Mississippi River's Marine...

  1. 33 CFR 3.40-40 - Sector Upper Mississippi River Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Sector Upper Mississippi River... Mississippi River Marine Inspection Zone and Captain of the Port Zone. Sector Upper Mississippi River's office is located in St. Louis, MO. The boundaries of Sector Upper Mississippi River's Marine...

  2. 33 CFR 3.40-40 - Sector Upper Mississippi River Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Sector Upper Mississippi River... Mississippi River Marine Inspection Zone and Captain of the Port Zone. Sector Upper Mississippi River's office is located in St. Louis, MO. The boundaries of Sector Upper Mississippi River's Marine...

  3. 33 CFR 3.40-40 - Sector Upper Mississippi River Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Sector Upper Mississippi River... Mississippi River Marine Inspection Zone and Captain of the Port Zone. Sector Upper Mississippi River's office is located in St. Louis, MO. The boundaries of Sector Upper Mississippi River's Marine...

  4. 33 CFR 3.40-40 - Sector Upper Mississippi River Marine Inspection Zone and Captain of the Port Zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Sector Upper Mississippi River... Mississippi River Marine Inspection Zone and Captain of the Port Zone. Sector Upper Mississippi River's office is located in St. Louis, MO. The boundaries of Sector Upper Mississippi River's Marine...

  5. Definition Of Touch-Sensitive Zones For Graphical Displays

    NASA Technical Reports Server (NTRS)

    Monroe, Burt L., III; Jones, Denise R.

    1988-01-01

    Touch zones defined simply by touching, while editing done automatically. Development of touch-screen interactive computing system, tedious task. Interactive Editor for Definition of Touch-Sensitive Zones computer program increases efficiency of human/machine communications by enabling user to define each zone interactively, minimizing redundancy in programming and eliminating need for manual computation of boundaries of touch areas. Information produced during editing process written to data file, to which access gained when needed by application program.

  6. Grain Boundary Chemistry in Mantle Rocks

    NASA Astrophysics Data System (ADS)

    Hiraga, T.; Anderson, I. M.; Kohlstedt, D. L.

    2002-12-01

    We show that the same elements segregate to olivine grain boundaries in both natural rocks and synthetic aggregates. We conclude that this chemical segregation is an energetically favorable phenomenon that will influence the physical and chemical properties of mantle rocks. Two natural samples with unaltered and tight grain boundaries were chosen. One is an ultramylonite from Balmuccia peridotite in the Ivrea Zone. The other is a basaltic rock with olivine phenocrysts from Kilauea, Hawaii. Two olivine phenocrysts often contact one another forming straight and long grain boundaries. Two synthetic aggregates, one composed of olivine + diopside and the other of olivine + anorthite, were synthesized. The diopside and anorthite powders were mechanically mixed with dried San Carlos olivine powder and subsequently isostatically hot-pressed inside an Fe jacket at 1373 K and 300 MPa in a gas-medium apparatus. Some of the hot-pressed samples were annealed at 1373 K and room pressure. Scanning-transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM/EDX) profiling was used to determine the chemical compositions of olivine grain boundaries. In this study, we used a Philips CM200 TEM/STEM equipped with a Schottky field emission gun (FEG) and operated at 200 kV to obtain a probe size (full width at half maximum) of 1.3-1.4 nm. The profiles across every grain boundary exhibited similar chemical features. The primary features are 1) significant Ca enrichment, 2) weak Si and Mg depletion, and 3) weak to significant Al and Ti enrichment. Both the enrichment and the depletion are restricted a zone <5 nm wide along the grain boundaries. The Ca concentration in the grain boundaries is positively correlated with that in the grains. Segregation can result from kinetic and thermodynamic effects. In nature, a decrease in the solubility of specific elements in the grains during cooling of a rock can cause segregation. However, the effect cannot explain the

  7. Boundary lubrication: Revisited

    NASA Technical Reports Server (NTRS)

    Jones, W. R., Jr.

    1982-01-01

    A review of the various lubrication regimes, with particular, emphasis on boundary lubrication, is presented. The types of wear debris and extent of surface damage is illustrated for each regime. The role of boundary surface films along with their modes of formation and important physical properties are discussed. In addition, the effects of various operating parameters on friction and wear in the boundary lubrication regime are considered.

  8. Coastal Zone Color Scanner

    NASA Technical Reports Server (NTRS)

    Johnson, B.

    1988-01-01

    The Coastal Zone Color Scanner (CZCS) spacecraft ocean color instrument is capable of measuring and mapping global ocean surface chlorophyll concentration. It is a scanning radiometer with multiband capability. With new electronics and some mechanical, and optical re-work, it probably can be made flight worthy. Some additional components of a second flight model are also available. An engineering study and further tests are necessary to determine exactly what effort is required to properly prepare the instrument for spaceflight and the nature of interfaces to prospective spacecraft. The CZCS provides operational instrument capability for monitoring of ocean productivity and currents. It could be a simple, low cost alternative to developing new instruments for ocean color imaging. Researchers have determined that with global ocean color data they can: specify quantitatively the role of oceans in the global carbon cycle and other major biogeochemical cycles; determine the magnitude and variability of annual primary production by marine phytoplankton on a global scale; understand the fate of fluvial nutrients and their possible affect on carbon budgets; elucidate the coupling mechanism between upwelling and large scale patterns in ocean basins; answer questions concerning the large scale distribution and timing of spring blooms in the global ocean; acquire a better understanding of the processes associated with mixing along the edge of eddies, coastal currents, western boundary currents, etc., and acquire global data on marine optical properties.

  9. Western boundary of Mesozoic North America

    SciTech Connect

    Chamberlain, V.E.; Lambert, R.

    1985-01-01

    The line most often used to delineate the western edge of cratonic North America is the strontium isotope line. Strontium isotopes, however, differentiate, essentially, between continental crust and oceanic crust. They cannot usually distinguish between old autochthonous continental crust and old allochthonous continental crust. Geophysical parameters are often better suited to this purpose. In many places in the Western Cordillera, notably in SE British Columbia, the use of the strontium isotope line as a cratonic boundary line conflicts with other evidence, including other isotopic evidence, geological field relations, paleomagnetic evidence and geophysical data. Magnetic and gravity anomalies, conductivity, heat flow and seismic data suggest that the cratonic boundary there is approximately along the line of Kootenay Lake (117/sup 0/ W). This boundary, which is also a magnetic quiet zone, continues south into Idaho, where it is on strike with the western edge of the Idaho Batholith. Further south, the western boundary of Mesozoic North American probably lay west of the basement quiet zone, at the pre-extension western edge of the Basin and Range Province. The geophysical evidence in northern Canada suggests that the Rocky Mountain Trench and the Tintina fault mark the cratonic edge of Mesozoic North America in that region.

  10. Pharmacokinetics of cefaclor AF: effects of age, antacids and H2-receptor antagonists.

    PubMed

    Satterwhite, J H; Cerimele, B J; Coleman, D L; Hatcher, B L; Kisicki, J; DeSante, K A

    1992-01-01

    The pharmacokinetics and bioavailability of cefaclor advanced formulation (cefaclor AF) were investigated in two studies, one comparing healthy elderly and younger volunteers and the other assessing the effects of an antacid and H2-receptor antagonist on cefaclor AF bioavailability. The pharmacokinetics of a 750 mg dose of cefaclor AF were studied in 30 subjects ranging in age from 65 to 84 years and 10 control subjects 21-45 years of age. Compared with controls, elderly subjects exhibited higher plasma concentrations of cefaclor which were attributed to lower plasma clearance. There was a strong association between age and renal function, and the plasma clearance of cefaclor was highly dependent upon renal function. Thus, elderly patients with impaired renal function had a reduced ability to eliminate cefaclor. Due to a short elimination half-life and wide therapeutic index, dosage adjustments are not necessary in patients exhibiting moderate renal dysfunction. The 15 healthy men in the second trial were crossed over to receive five treatments, including cefaclor AF (500 mg) alone, cefaclor AF with or preceded by cimetidine, cefaclor AF followed by Maalox TC and cefaclor immediate release (500 mg) alone. Cefaclor AF and immediate release cefaclor had similar bioavailability, but plasma concentrations were maintained for a longer period of time when cefaclor AF was administered. Cimetidine did not alter the bioavailability of cefaclor AF but Maalox TC, coadministered with cefaclor AF, reduced the extent of absorption. This suggests that cefaclor AF bioavailability is influenced by the antacid Maalox TC but not by H2-receptor antagonist cimetidine. PMID:1287615

  11. Satellite-Derived Management Zones

    NASA Technical Reports Server (NTRS)

    Lepoutre, Damien; Layrol, Laurent

    2005-01-01

    The term "satellite-derived management zones" (SAMZ) denotes agricultural management zones that are subdivisions of large fields and that are derived from images of the fields acquired by instruments aboard Earth-orbiting satellites during approximately the past 15 years. "SAMZ" also denotes the methodology and the software that implements the methodology for creating such zones. The SAMZ approach is one of several products of continuing efforts to realize a concept of precision agriculture, which involves optimal variations in seeding, in application of chemicals, and in irrigation, plus decisions to farm or not to farm certain portions of fields, all in an effort to maximize profitability in view of spatial and temporal variations in the growth and health of crops, and in the chemical and physical conditions of soils. As used here, "management zone" signifies, more precisely, a subdivision of a field within which the crop-production behavior is regarded as homogeneous. From the perspective of precision agriculture, management zones are the smallest subdivisions between which the seeding, application of chemicals, and other management parameters are to be varied. In the SAMZ approach, the main sources of data are the archives of satellite imagery that have been collected over the years for diverse purposes. One of the main advantages afforded by the SAMZ approach is that the data in these archives can be reused for purposes of precision agriculture at low cost. De facto, these archives contain information on all sources of variability within a field, including weather, crop types, crop management, soil types, and water drainage patterns. The SAMZ methodology involves the establishment of a Web-based interface based on an algorithm that generates management zones automatically and quickly from archival satellite image data in response to requests from farmers. A farmer can make a request by either uploading data describing a field boundary to the Web site or else

  12. 75 FR 12729 - Foreign-Trade Zone 133-Quad-Cities, Iowa/Illinois; Application for Expansion

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... (Board Order 338, 51 FR 40238, 11/5/86). After a subsequent minor boundary modification was approved on... Foreign-Trade Zones Board Foreign-Trade Zone 133--Quad-Cities, Iowa/Illinois; Application for Expansion An... Zone, Inc., grantee of FTZ 133, requesting authority to expand the zone within the...

  13. Penipyridones A-F, Pyridone Alkaloids from Penicillium funiculosum.

    PubMed

    Zhou, Haibo; Li, Liyuan; Wu, Chongming; Kurtán, Tibor; Mándi, Attila; Liu, Yankai; Gu, Qianqun; Zhu, Tianjiao; Guo, Peng; Li, Dehai

    2016-07-22

    Six new pyridone alkaloids, named penipyridones A-F (1-6), were isolated from the fermentation broth of an Antarctic moss-derived fungus, Penicillium funiculosum GWT2-24. Their structures were elucidated from extensive NMR and MS data. Although they possess the same major chromophore and some of them presented almost mirror ECD spectra, their absolute configurations were found to be uniformly S, as evidenced by X-ray single-crystal diffraction analysis, stereocontrolled total synthesis, and chemical conversions. TDDFT-ECD calculations of compounds 3 and 6 revealed that subtle conformational changes are responsible for the significantly different ECD curves. None of the compounds were cytotoxic (IC50 > 50 μM), while compounds 1, 2, 5, and 7 elicited lipid-lowering activity in HepG2 hepatocytes. PMID:27359163

  14. Optimised secure transmission through untrusted AF relays using link adaptation

    NASA Astrophysics Data System (ADS)

    Taki, Mehrdad; Sadeghi, Mohammad

    2016-05-01

    A new transmission scheme is presented for a two-hop relay network including two AF relays, considering physical layer security where relays are not able to detect signal with an acceptable bit error rate (BER) but the combined received signal is detected with an acceptable BER at the final receiver. It is assumed that there is no direct path between the transmitter and the receiver (relay network without diversity). Adaptive modulation and coding is utilised at the transmitter and transmission powers of the transmitter and of the relays are continuously adapted provisioning individual average power constraint for each node. Numerical evaluations show that an acceptable performance degradation is seen by the proposed secure relaying scheme compared to the optimum relay selection scheme without security constraint.

  15. NATIONAL PARK BOUNDARIES

    EPA Science Inventory

    The National Park Service has produced a data base of boundaries for its National Parks. A copy of this data was downloaded from the National Parks Service ftp site by Region 10. These digital boundaries represent the best guess and data that could be collected in a short time....

  16. The Atmospheric Boundary Layer

    ERIC Educational Resources Information Center

    Tennekes, Hendrik

    1974-01-01

    Discusses some important parameters of the boundary layer and effects of turbulence on the circulation and energy dissipation of the atmosphere. Indicates that boundary-layer research plays an important role in long-term forecasting and the study of air-pollution meteorology. (CC)

  17. Evaluation of the atoxigenic Aspergillus flavus strain AF36 in pistachio orchards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The atoxigenic strain Aspergillus flavus AF36, which has been extensively used as a biocontrol agent in commercial corn and cotton fields to reduce aflatoxin contamination, was applied in research pistachio orchards from 2002 to 2005 and in commercial pistachio orchards from 2008 to 2011. AF36 was a...

  18. Vadose zone microbiology

    SciTech Connect

    Kieft, Thomas L.; Brockman, Fred J.

    2001-01-17

    The vadose zone is defined as the portion of the terrestrial subsurface that extends from the land surface downward to the water table. As such, it comprises the surface soil (the rooting zone), the underlying subsoil, and the capillary fringe that directly overlies the water table. The unsaturated zone between the rooting zone and the capillary fringe is termed the "intermediate zone" (Chapelle, 1993). The vadose zone has also been defined as the unsaturated zone, since the sediment pores and/or rock fractures are generally not completely water filled, but instead contain both water and air. The latter characteristic results in the term "zone of aeration" to describe the vadose zone. The terms "vadose zone," "unsaturated zone", and "zone of aeration" are nearly synonymous, except that the vadose zone may contain regions of perched water that are actually saturated. The term "subsoil" has also been used for studies of shallow areas of the subsurface immediately below the rooting zone. This review focuses almost exclusively on the unsaturated region beneath the soil layer since there is already an extensive body of literature on surface soil microbial communities and process, e.g., Paul and Clark (1989), Metting (1993), Richter and Markowitz, (1995), and Sylvia et al. (1998); whereas the deeper strata of the unsaturated zone have only recently come under scrutiny for their microbiological properties.

  19. Mutant U2AF1 Expression Alters Hematopoiesis and Pre-mRNA Splicing In Vivo

    PubMed Central

    Shirai, Cara Lunn; Ley, James N.; White, Brian S.; Kim, Sanghyun; Tibbitts, Justin; Shao, Jin; Ndonwi, Matthew; Wadugu, Brian; Duncavage, Eric J.; Okeyo-Owuor, Theresa; Liu, Tuoen; Griffith, Malachi; McGrath, Sean; Magrini, Vincent; Fulton, Robert S.; Fronick, Catrina; O’Laughlin, Michelle; Graubert, Timothy A.; Walter, Matthew J.

    2015-01-01

    SUMMARY Heterozygous somatic mutations in the spliceosome gene U2AF1 occur in ~11% of patients with myelodysplastic syndromes (MDS), the most common adult myeloid malignancy. It is unclear how these mutations contribute to disease. We examined in vivo hematopoietic consequences of the most common U2AF1 mutation using a doxycycline-inducible transgenic mouse model. Mice expressing mutant U2AF1(S34F) display altered hematopoiesis and changes in pre-mRNA splicing in hematopoietic progenitor cells by whole transcriptome analysis (RNA-seq). Integration with human RNA-seq datasets determined that common mutant U2AF1-induced splicing alterations are enriched in RNA processing genes, ribosomal genes, and recurrently-mutated MDS and acute myeloid leukemia-associated genes. These findings support the hypothesis that mutant U2AF1 alters downstream gene isoform expression, thereby contributing to abnormal hematopoiesis in MDS patients. PMID:25965570

  20. Boundary element and finite element coupling for aeroacoustics simulations

    NASA Astrophysics Data System (ADS)

    Balin, Nolwenn; Casenave, Fabien; Dubois, François; Duceau, Eric; Duprey, Stefan; Terrasse, Isabelle

    2015-08-01

    We consider the scattering of acoustic perturbations in the presence of a flow. We suppose that the space can be split into a zone where the flow is uniform and a zone where the flow is potential. In the first zone, we apply a Prandtl-Glauert transformation to recover the Helmholtz equation. The well-known setting of boundary element method for the Helmholtz equation is available. In the second zone, the flow quantities are space dependent, we have to consider a local resolution, namely the finite element method. Herein, we carry out the coupling of these two methods and present various applications and validation test cases. The source term is given through the decomposition of an incident acoustic field on a section of the computational domain's boundary. Validations against analytic, another numerical method and measurements on different test cases are presented.

  1. A diffuse plate boundary model for Indian Ocean tectonics

    NASA Technical Reports Server (NTRS)

    Wiens, D. A.; Demets, C.; Gordon, R. G.; Stein, S.; Argus, D.

    1985-01-01

    It is suggested that motion along the virtually aseismic Owen fracture zone is negligible, so that Arabia and India are contained within a single Indo-Arabian plate divided from the Australian plate by a diffuse boundary. The boundary is a zone of concentrated seismicity and deformation commonly characterized as 'intraplate'. The rotation vector of Australia relative to Indo-Arabia is consistent with the seismologically observed 2 cm/yr of left-lateral strike-slip along the Ninetyeast Ridge, north-south compression in the Central Indian Ocean, and the north-south extension near Chagos.

  2. Atrial Fibrillation Management Strategies in Routine Clinical Practice: Insights from the International RealiseAF Survey

    PubMed Central

    Chiang, Chern-En; Naditch-Brûlé, Lisa; Brette, Sandrine; Silva-Cardoso, José; Gamra, Habib; Murin, Jan; Zharinov, Oleg J.; Steg, Philippe Gabriel

    2016-01-01

    Background Atrial fibrillation (AF) can be managed with rhythm- or rate-control strategies. There are few data from routine clinical practice on the frequency with which each strategy is used and their correlates in terms of patients’ clinical characteristics, AF control, and symptom burden. Methods RealiseAF was an international, cross-sectional, observational survey of 11,198 patients with AF. The aim of this analysis was to describe patient profiles and symptoms according to the AF management strategy used. A multivariate logistic regression identified factors associated with AF management strategy at the end of the visit. Results Among 10,497 eligible patients, 53.7% used a rate-control strategy, compared with 34.5% who used a rhythm-control strategy. In 11.8% of patients, no clear strategy was stated. The proportion of patients with AF-related symptoms (EHRA Class > = II) was 78.1% (n = 4396/5630) for those using a rate-control strategy vs. 67.8% for those using a rhythm-control strategy (p<0.001). Multivariate logistic regression analysis revealed that age <75 years or the paroxysmal or persistent form of AF favored the choice of a rhythm-control strategy. A change in strategy was infrequent, even in patients with European Heart Rhythm Association (EHRA) Class > = II. Conclusions In the RealiseAF routine clinical practice survey, rate control was more commonly used than rhythm control, and a change in strategy was uncommon, even in symptomatic patients. In almost 12% of patients, no clear strategy was stated. Physician awareness regarding optimal management strategies for AF may be improved. PMID:26800084

  3. A general boundary capability embedded in an orthogonal mesh

    SciTech Connect

    Hewett, D.W.; Yu-Jiuan Chen

    1995-07-01

    The authors describe how they hold onto orthogonal mesh discretization when dealing with curved boundaries. Special difference operators were constructed to approximate numerical zones split by the domain boundary; the operators are particularly simple for this rectangular mesh. The authors demonstrated that this simple numerical approach, termed Dynamic Alternating Direction Implicit, turned out to be considerably more efficient than more complex grid-adaptive algorithms that were tried previously.

  4. Lessons from the dissection of the activation functions (AF-1 and AF-2) of the estrogen receptor alpha in vivo.

    PubMed

    Arnal, Jean-François; Fontaine, Coralie; Abot, Anne; Valera, Marie-Cécile; Laurell, Henrik; Gourdy, Pierre; Lenfant, Françoise

    2013-06-01

    Estrogens influence most of the physiological processes in mammals, including but not limited to reproduction, cognition, behavior, vascular system, metabolism and bone integrity. Given this widespread role for estrogen in human physiology, it is not surprising that estrogen influence the pathophysiology of numerous diseases, including cancer (of the reproductive tract as breast, endometrial but also colorectal, prostate,…), as well as neurodegenerative, inflammatory-immune, cardiovascular and metabolic diseases, and osteoporosis. These actions are mediated by the activation of estrogen receptors (ER) alpha (ERα) and beta (ERβ), which regulate target gene transcription (genomic action) through two independent activation functions (AF)-1 and AF-2, but can also elicit rapid membrane initiated steroid signals (MISS). Targeted ER gene inactivation has shown that although ERβ plays an important role in the central nervous system and in the heart, ERα appears to play a prominent role in most of the other tissues. Pharmacological activation or inhibition of ERα and/or ERβ provides already the basis for many therapeutic interventions, from hormone replacement at menopause to prevention of the recurrence of breast cancer. However, the use of these estrogens or selective estrogen receptors modulators (SERMs) have also induced undesired effects. Thus, an important challenge consists now to uncouple the beneficial actions from other deleterious ones. The in vivo molecular "dissection" of ERα represents both a molecular and integrated approach that already allowed to delineate in mouse the role of the main "subfunctions" of the receptor and that could pave the way to an optimization of the ER modulation. PMID:23200732

  5. Earthquake supercycle in subduction zones controlled by the downdip width of the seismogenic zone

    NASA Astrophysics Data System (ADS)

    Herrendörfer, Robert; van Dinther, Ylona; Gerya, Taras; Dalguer, Luis Angel

    2015-04-01

    Supercycles describe a long-term cluster of megathrust earthquakes that consist of partial ruptures before a complete failure of a subduction zone segment (Sieh et al. 2008, Goldfinger et al. 2013). The controls on supercycles remain unclear, although structural or fault frictional heterogeneities were proposed (Sieh et al. 2008). We recognize that supercycles have been suggested in those subduction zones (Sieh et al. 2008, Goldfinger et al. 2013, Metois et al. 2014, Chlieh et al. 2014) for which the seismogenic zone downdip width is estimated (Heuret et al. 2011, Hayes et al. 2012, Hayes et al. 2013) to be larger than average. Here we assess this potential link between the seismogenic zone downdip width and supercycles. For this purpose we use the continuum-based seismo-mechanical model of megathrust earthquake cycles in subduction zones (Van Dinther et al. 2013), which was validated through a comparison against scaled analogue subduction experiments (Corbi et al. 2013). The two-dimensional numerical model setup consists of a visco-elastic wedge underthrusted by a rigid plate and a frictional boundary layer simulating the megathrust. In this boundary layer, we evaluate a non-associative Drucker-Prager plasticity with pressure dependent yield strength and a strongly rate-dependent friction formulation. The velocity-weakening seismogenic zone with a downdip width W is limited up-and downdip by velocity-strengthening regions. In our numerical models, an increasing seismogenic zone downdip width leads to a transition from ordinary cycles of similar sized complete ruptures to supercycles. For supercycles in wide seismogenic zones, we demonstrate how interseismic deformation accompanied by partial ruptures effectively increases the stress throughout the seismogenic zone until a crack-like superevent releases most of the accumulated stresses. Our findings suggest that supercycles are more likely to occur in subduction zones with a large seismogenic downdip width due to a

  6. The ULF wave foreshock boundary: Cluster observations

    NASA Astrophysics Data System (ADS)

    Andres, N.; Meziane, K.; Mazelle, C. X.; Bertucci, C.; Gomez, D. O.

    2013-12-01

    In the upstream region of the bow shock, the interaction of backstreaming ions with the incoming solar wind gives rise to a number of plasma instabilities from which ultra-low frequency (ULF) waves can grow. Due to the finite growth rate, it is expected that the region of ULF wave activity is spatially localized in the ion foreshock. Observational evidence of the ULF wave foreshock boundary has accumulated over the last three decades. Among other things, it has been shown that the geometrical characteristics of the boundary are very sensitive to the interplanetary magnetic field (IMF) cone angle. In the present work, we aimed at revisiting the properties of the ULF wave foreshock boundary. For this purpose, we use the first three years of magnetic field data from the flux gate magnetometer (FGM), and the plasma densities and velocities from the hot ion analyzer (HIA) low-geometry factor side on board RUMBA (SC 1). We use a specific and accurate criterion for the determination of boundary crossings, and a 3-D structure bow shock model to reconstruct the foreshock geometry. In particular, our criterion is used to qualitatively measure the differences between the magnetic field in the wave and no-wave zones, taking into account possible rotations of the IMF. A new identification of the ULF wave foreshock boundary is presented and it is compared with previous results reported in the literature as well as with theoretical predictions.

  7. Shear rupture under constant normal stiffness boundary conditions

    NASA Astrophysics Data System (ADS)

    Bewick, R. P.; Kaiser, P. K.; Bawden, W. F.

    2014-11-01

    A grain based Distinct Element Method and its embedded Grain Based Method are used to simulate the fracturing processes leading to shear rupture zone creation in a calibrated massive (non-jointed) brittle rock specimen deformed in direct shear under constant normal stiffness boundary conditions. Under these boundary conditions, shear rupture zone creation relative to the shear stress versus applied horizontal displacement (load-displacement) curve occurs pre-peak, before the maximum peak shear strength is reached. This is found to be the result of a normal stress feedback process caused by the imposed shear displacement which couples increases in normal stress, due to rupture zone dilation, with shear stress, producing a complex normal-shear stress-path that reaches and then follows the rock's yield (strength) envelope. While the yield envelope is followed, the shear strength increases further and shear stress oscillations (repeated stress drops followed by re-strengthening periods) in the load-displacement curves occur due to fracture creation as the rupture zone geometry smoothens. Once the maximum peak strength is reached (after a series of shear stress oscillations) the largest stress drops occur as the ultimate or residual shear strength is approached. The simulation results provide insight into the fracturing process during rupture zone creation and improve the understanding of the shear stress versus applied horizontal displacement response, as well as the stick-slip behaviour of shear rupture zones that are being created under constant normal stiffness boundary conditions.

  8. The effect of boundary-layer turbulence on mixing in heated jets

    NASA Astrophysics Data System (ADS)

    Strykowski, P. J.; Russ, S.

    1992-05-01

    The mixing properties of a heated axisymmetric jet at a density ratio of 0.55 were examined for initially laminar and turbulent separated boundary layers. Initially laminar jets displayed large intermittent spread rates with half-angles up to 45 deg and a corresponding rapid decay af the streamwise velocity and temperature on the jet axis. When the boundary layer was disturbed upstream of the nozzle exit, creating an initially turbulent separated layer, the jet mixing was significantly reduced. Flow visualization revealed that the turbulent conditions eliminated the intermittent nature of the jet spreading, producing constant spreading rates at half-angles near 10 deg.

  9. Hsp90 Directly Modulates the Spatial Distribution of AF9/MLLT3 and Affects Target Gene Expression*

    PubMed Central

    Lin, Jeffrey J.; Hemenway, Charles S.

    2010-01-01

    AF9/MLLT3 contributes to the regulation of the gene encoding the epithelial sodium channel α, ENaCα, in renal tubular cells. Specifically, increases in AF9 protein lead to a reduction in ENaCα expression and changes in AF9 activity appear to be an important component of aldosterone signaling in the kidney. Whereas AF9 is found in the nucleus where it interacts with the histone H3 lysine 79 methyltransferase, Dot1, AF9 is also present in the cytoplasm. Data presented in this report indicate that the heat shock protein Hsp90 directly and specifically interacts with AF9 as part of an Hsp90-Hsp70-p60/Hop chaperone complex. Experimental manipulation of Hsp90 function by the inhibitor novobiocin, but not 17-AAG, results in redistribution of AF9 from a primarily nuclear to cytoplasmic location. Knockdown of Hsp90 with siRNA mimics the effect elicited by novobiocin. As expected, a shift in AF9 from the nucleus to the cytoplasm in response to Hsp90 interference leads to increased ENaCα expression. This is accompanied by a decrease in AF9 occupancy at the ENaCα promoter. Our data suggest that the interaction of Hsp90, Hsp70, and p60/Hop with AF9 is necessary for the proper subnuclear localization and activity of AF9. AF9 is among a growing number of nuclear proteins recognized to rely on the Hsp90 complex for nuclear targeting. PMID:20159978

  10. Hybrid Zones: Windows on Climate Change

    PubMed Central

    Larson, Erica L.; Harrison, Richard G.

    2016-01-01

    Defining the impacts of anthropogenic climate change on biodiversity and species distributions is currently a high priority. Niche models focus primarily on predicted changes in abiotic factors; however, species interactions and adaptive evolution will impact the ability of species to persist in the face of changing climate. Our review focuses on the use of hybrid zones to monitor species' responses to contemporary climate change. Monitoring hybrid zones provides insight into how range boundaries shift in response to climate change by illuminating the combined effects of species interactions and physiological sensitivity. At the same time, the semi-permeable nature of species boundaries allows us to document adaptive introgression of alleles associated with response to climate change. PMID:25982153

  11. [Factor AF2--the 4th column in tumor therapy. Documentation No.22].

    PubMed

    Kast, A; Hauser, S P

    1990-04-17

    Factor AF2 is an extract from the spleen and liver of sheep embryos and lambs. The product contains biotechnologically produced, chromatographically uniform, molecularly standardized polypeptides, glycopeptides, glycolipids and nucleotides, deproteinized and free of pyrogens'. Factor AF2 is intended mainly for use in 'supportive antitumour therapy', as a 'biological antiemetic and analgesic'. The proposed duration of treatment is usually more than six months. The dosage varies considerably according to the indication. The average daily costs are, therefore, between DM 4.- (prevention of recurrence) and DM 107.- (adjuvant to chemotherapy). Allergic reactions have been reported in 'rare cases'. Factor AF2 was developed in the forties by Guarnieri in Rome. Since 1984, Factor AF2 is 'biotechnologically' produced and as a 'biological response modifier' (BRM) in the oncotherapy distributed by Biosyn Arzneimittel GmbH, Stuttgart. Dr. rer. nat. T. Stiefel and Dr. rer. nat. H. Porcher are the representatives of Biosyn Arzneimittel GmbH. In the past, both worked with Vitorgan Arzneimittel GmbH (cytoplasmatic therapy according to Theurer). It is claimed that Factor AF2 contains 'immunomodulating and immunorestorative biomolecules' assignable to the BRM group. Terms and investigations from current immunological research are applied to Factor AF2. No preclinical investigations are available which demonstrate any cytostatic effect of Factor AF2. In vivo, no effects were observed on the transplanted meth-A-sarcoma in mice.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2349412

  12. The Ras Target AF-6 is a Substrate of the Fam Deubiquitinating Enzyme

    PubMed Central

    Taya, Shinichiro; Yamamoto, Takaharu; Kano, Kyoko; Kawano, Yoji; Iwamatsu, Akihiro; Tsuchiya, Tomoko; Tanaka, Keiji; Kanai-Azuma, Masami; Wood, Stephen A.; Mattick, John S.; Kaibuchi, Kozo

    1998-01-01

    The Ras target AF-6 has been shown to serve as one of the peripheral components of cell–cell adhesions, and is thought to participate in cell–cell adhesion regulation downstream of Ras. We here purified an AF-6-interacting protein with a molecular mass of ∼220 kD (p220) to investigate the function of AF-6 at cell–cell adhesions. The peptide sequences of p220 were identical to the amino acid sequences of mouse Fam. Fam is homologous to a deubiquitinating enzyme in Drosophila, the product of the fat facets gene. Recent genetic analyses indicate that the deubiquitinating activity of the fat facets product plays a critical role in controlling the cell fate. We found that Fam accumulated at the cell–cell contact sites of MDCKII cells, but not at free ends of plasma membranes. Fam was partially colocalized with AF-6 and interacted with AF-6 in vivo and in vitro. We also showed that AF-6 was ubiquitinated in intact cells, and that Fam prevented the ubiquitination of AF-6. PMID:9722616

  13. Critical behavior of a triangular lattice Ising AF/FM bilayer

    NASA Astrophysics Data System (ADS)

    Žukovič, M.; Bobák, A.

    2016-03-01

    We study a bilayer Ising spin system consisting of antiferromagnetic (AF) and ferromagnetic (FM) triangular planes, coupled by ferromagnetic exchange interaction, by standard Monte Carlo and parallel tempering methods. The AF/FM bilayer is found to display the critical behavior completely different from both the single FM and AF constituents as well as the FM/FM and AF/AF bilayers. Namely, by finite-size scaling (FSS) analysis we identify at the same temperature a standard Ising transition from the paramagnetic to FM state in the FM plane that induces a ferrimagnetic state with a finite net magnetic moment in the AF plane. At lower temperatures there is another phase transition, that takes place only in the AF plane, to different ferrimagnetic state with spins on two sublattices pointing parallel and on one sublattice antiparallel to the spins on the FM plane. FSS indicates that the corresponding critical exponents are close to the two-dimensional three-state ferromagnetic Potts model values.

  14. U2AF1 Mutations Alter Sequence Specificity of pre-mRNA Binding and Splicing

    PubMed Central

    Okeyo-Owuor, Theresa; White, Brian S.; Chatrikhi, Rakesh; Mohan, Dipika R.; Kim, Sanghyun; Griffith, Malachi; Ding, Li; Ketkar-Kulkarni, Shamika; Hundal, Jasreet; Laird, Kholiswa M.; Kielkopf, Clara L.; Ley, Timothy J.; Walter, Matthew J.; Graubert, Timothy A.

    2014-01-01

    We previously identified missense mutations in the U2AF1 splicing factor affecting codons S34 (S34F and S34Y) or Q157 (Q157R and Q157P) in 11% of patients with de novo myelodysplastic syndromes (MDS). Although the role of U2AF1 as an accessory factor in the U2 snRNP is well established, it is not yet clear how mutations affect splicing or contribute to MDS pathophysiology. We analyzed splice junctions in RNA-seq data generated from transfected CD34+ hematopoietic cells and found significant differences in the abundance of known and novel junctions in samples expressing mutant U2AF1 (S34F). For selected transcripts, splicing alterations detected by RNA-seq were confirmed by analysis of primary de novo MDS patient samples. These effects were not due to impaired U2AF1 (S34F) localization as it co-localized normally with U2AF2 within nuclear speckles. We further found evidence in the RNA-seq data for decreased affinity of U2AF1 (S34F) for uridine (relative to cytidine) at the e-3 position immediately upstream of the splice acceptor site and corroborated this finding using affinity binding assays. These data suggest that the S34F mutation alters U2AF1 function in the context of specific RNA sequences, leading to aberrant alternative splicing of target genes, some of which may be relevant for MDS pathogenesis. PMID:25311244

  15. Simulating weld-fusion boundary microstructures in aluminum alloys

    NASA Astrophysics Data System (ADS)

    Kostrivas, Anastasios D.; Lippold, John C.

    2004-02-01

    A fundamental study of weld-fusion boundary microstructure evolution in aluminum alloys was conducted in an effort to understand equiaxed grain zone formation and fusion boundary nucleation and growth phenomena. In addition to commercial aluminum alloys, experimental Mg-bearing alloys with Zr and Sc additions were studied along with the widely used Cu- and Licontaining alloy 2195-T8. This article describes work conducted to clarify the interrelation among composition, base metal substrate, and temperature as they relate to nucleation and growth phenomena at the fusion boundary.

  16. The Pleistocene/Holocene boundary in south-western Sweden

    NASA Astrophysics Data System (ADS)

    Olausson, E.

    The boundary between the Pleistocene/Holocene epochs was placed at 10,000 C(14) years B.P. (Libby half time) by the Holocene Commission. In search of a stratotype locality three cores from the province of Bohusian, south-western Sweden, were scrutinized concerning different geophysical, geochemical and bioastratigraphical parameters. The marine sequences of the cores from Moltemyr and Solberga reveal a distinct boundary and a transition zone respectively which meet the requirements laid down by the Holocene Commission. The suggested age of the lithological boundary is c. 10,200-10,300 years B.P.

  17. A study of tornadic thunderstorm interactions with thermal boundaries

    NASA Technical Reports Server (NTRS)

    Maddox, R. A.; Hoxit, L. R.; Chappell, C. F.

    1980-01-01

    A study of tornadic thunderstorm interactions with thermal boundaries using a model of subcloud wind profiles is presented. Within a hot, moist, and conditionally unstable air mass, warm thermal advection and surface friction cause the winds to veer and increase with height, while within a cool, moist air mass cool thermal advection and friction combine to produce a wind profile that has maximum speeds near the surface and veers little with height. The spatial distribution of different wind profiles and moisture contents within the boundary layer may act together to maximize mesoscale moisture contents, convergence, and cyclonic vorticity within a narrow mixing zone along the thermal boundary.

  18. Ternary complex formation and competition quench fluorescence of ZnAF family zinc sensors.

    PubMed

    Staszewska, Anna; Kurowska, Ewa; Bal, Wojciech

    2013-11-01

    Our current understanding of the intracellular thermodynamics and kinetics of Zn(ii) ions is largely based on the application of fluorescent sensor molecules, used to study and visualize the concentration, distribution and transport of Zn(ii) ions in real time. Such agents are designed for high selectivity for zinc in respect to other biological metal ions. However, the issue of their sensitivity to physiological levels of low molecular weight Zn(ii) ligands (LMWLs) has not been addressed. We followed the effects of eight such compounds on the fluorescence of ZnAF-1 and ZnAF-2F, two representatives of the ZnAF family of fluorescein-based zinc sensors containing the N,N-bis(2-pyridylmethyl)ethylenediamine chelating unit. Fluorescence titrations of equimolar Zn(ii)-ZnAF-1 and Zn(ii)-ZnAF-2F solutions with acetate, phosphate, citrate, glycine, glutamic acid, histidine, ATP and GSH demonstrated strong fluorescence quenching. These results are interpreted in terms of an interplay of the formation of the [ZnAF-Zn(ii)-LMWL] ternary complexes and the competition for Zn(ii) between ZnAF and LMWLs. UV-vis spectroscopic titrations revealed the existence of supramolecular interactions between the fluorescein moiety of ZnAF-1 and ATP and His, which, however, did not contribute to fluorescence quenching. Therefore, the obtained results show that the ZnAF sensors, other currently used zinc sensors containing the N,N-bis(2-pyridylmethyl)ethylenediamine unit, and, in general, all sensors that do not saturate the Zn(ii) coordination sphere may co-report cellular metabolites and Zn(ii) ions, leading to misrepresentations of the concentrations and fluxes of biological zinc. PMID:23939683

  19. Hospitalizations in patients with atrial fibrillation: an analysis from ROCKET AF

    PubMed Central

    DeVore, Adam D.; Hellkamp, Anne S.; Becker, Richard C.; Berkowitz, Scott D.; Breithardt, Guenter; Hacke, Werner; Halperin, Jonathan L.; Hankey, Graeme J.; Mahaffey, Kenneth W.; Nessel, Christopher C.; Singer, Daniel E.; Fox, Keith A. A.; Patel, Manesh R.; Piccini, Jonathan P.

    2016-01-01

    Aims The high costs associated with treatment for atrial fibrillation (AF) are primarily due to hospital care, but there are limited data to understand the reasons for and predictors of hospitalization in patients with AF. Methods and results The ROCKET AF trial compared rivaroxaban with warfarin for stroke prophylaxis in AF. We described the frequency of and reasons for hospitalization during study follow-up and utilized Cox proportional hazards models to assess for baseline characteristics associated with all-cause hospitalization. Of 14 171 patients, 14% were hospitalized at least once. Of 2614 total hospitalizations, 41% were cardiovascular including 4% for AF; of the remaining, 12% were for bleeding. Compared with patients not hospitalized, hospitalized patients were older (74 vs. 72 years), and more frequently had diabetes (46 vs. 39%), prior MI (23 vs. 16%), and paroxysmal AF (19 vs. 17%), but less frequently had prior transient ischaemic attack/stroke (49 vs. 56%). After multivariable adjustment, lung disease [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.29–1.66], diabetes [1.22, (1.11–1.34)], prior MI [1.27, (1.13–1.42)], and renal dysfunction [HR 1.07 per 5 unit GFR < 65 mL/min, (1.04–1.10)] were associated with increased hospitalization risk. Treatment assignment was not associated with differential rates of hospitalization. Conclusion Nearly 1 in 7 of the moderate-to-high-risk patients with AF enrolled in this trial was hospitalized within 2 years, and both AF and bleeding were rare causes of hospitalization. Further research is needed to determine whether care pathways directed at comorbid conditions among AF patients could reduce the need for and costs associated with hospitalization. PMID:27174904

  20. Map showing lava-flow hazard zones, Island of Hawaii

    USGS Publications Warehouse

    Wright, Thomas L.; Chun, Jon Y.F.; Exposo, Jean; Heliker, Christina; Hodge, Jon; Lockwood, John P.; Vogt, Susan M.

    1992-01-01

    This map shows lava-flow hazard zones for the five volcanoes on the Island of Hawaii. Volcano boundaries are shown as heavy, dark bands, reflecting the overlapping of lava flows from adjacent volcanoes along their common boundary. Hazard-zone boundaries are drawn as double lines because of the geologic uncertainty in their placement. Most boundaries are gradational, and the change In the degree of hazard can be found over a distance of a mile or more. The general principles used to place hazard-zone boundaries are discussed by Mullineaux and others (1987) and Heliker (1990). The differences between the boundaries presented here and in Heliker (1990) reflect new data used in the compilation of a geologic map for the Island of Hawaii (E.W. Wolfe and Jean Morris, unpub. data, 1989). The primary source of information for volcano boundaries and generalized ages of lava flows for all five volcanoes on the Island of Hawaii is the geologic map of Hawaii (E.W. Wolfe and Jean Morris, unpub. data, 1989). More detailed information is available for the three active volcanoes. For Hualalai, see Moore and others (1987) and Moore and Clague (1991); for Mauna Loa, see Lockwood and Lipman (1987); and for Kilauea, see Holcomb (1987) and Moore and Trusdell (1991).

  1. Psychodynamic Perspective on Therapeutic Boundaries

    PubMed Central

    Bridges, Nancy A.

    1999-01-01

    Discussion of boundaries in therapeutic work most often focuses on boundary maintenance, risk management factors, and boundary violations. The psychodynamic meaning and clinical management of boundaries in therapeutic relationships remains a neglected area of discourse. Clinical vignettes will illustrate a psychodynamic, developmental-relational perspective using boundary dilemmas to deepen and advance the therapeutic process. This article contributes to the dialogue about the process of making meaning and constructing therapeutically useful and creative boundaries that further the psychotherapeutic process. PMID:10523432

  2. The Inhibition of Inflammasome by Brazilian Propolis (EPP-AF)

    PubMed Central

    Hori, Juliana I.; Zamboni, Dario S.; Carrão, Daniel B.; Goldman, Gustavo Henrique; Berretta, Andresa A.

    2013-01-01

    Propolis extracts have gained the attention of consumers and researchers due to their unique chemical compositions and functional properties such as its anti-inflammatory activity. Recently, it was described a complex that is also important in inflammatory processes, named inflammasome. The inflammasomes are a large molecular platform formed in the cell cytosol in response to stress signals, toxins, and microbial infections. Once activated, the inflammasome induces caspase-1, which in turn induces the processing of inflammatory cytokines such as IL-1β and IL-18. So, to understand inflammasomes regulation becomes crucial to treat several disorders including autoinflammatory diseases. Since green propolis extracts are able to regulate inflammatory pathways, this work purpose was to investigate if this extract could also act on inflammasomes regulation. First, the extract was characterized and it demonstrated the presence of important compounds, especially Artepillin C. This extract was effective in reducing the IL-1β secretion in mouse macrophages and this reduction was correlated with a decrease in activation of the protease caspase-1. Furthermore, we found that the extract at a concentration of 30 μg/mL was not toxic to the cells even after a 18-hour treatment. Altogether, these data indicate that Brazilian green propolis (EPP-AF) extract has a role in regulating the inflammasomes. PMID:23690844

  3. Flacourtosides A-F, phenolic glycosides isolated from Flacourtia ramontchi.

    PubMed

    Bourjot, Mélanie; Leyssen, Pieter; Eydoux, Cécilia; Guillemot, Jean-Claude; Canard, Bruno; Rasoanaivo, Philippe; Guéritte, Françoise; Litaudon, Marc

    2012-04-27

    In an effort to identify novel inhibitors of chikungunya (CHIKV) and dengue (DENV) virus replication, a systematic study with 820 ethyl acetate extracts of madagascan plants was performed in a virus-cell-based assay for CHIKV, and a DENV NS5 RNA-dependent RNA polymerase (RdRp) assay. The extract obtained from the stem bark of Flacourtia ramontchi was selected for its significant activity in both assays. Six new phenolic glycosides, named flacourtosides A-F (1-6), phenolic glycosides itoside H, xylosmin, scolochinenoside D, and poliothrysoside, and betulinic acid 3β-caffeate were obtained using the bioassay-guided isolation process. Their structures were elucidated by comprehensive analyses of NMR spectroscopic and mass spectrometric data. Even though several extracts and fractions showed significant selective antiviral activity in the CHIKV virus-cell-based assay, none of the purified compounds did. However, in the DENV RNA polymerase assay, significant inhibition was observed with betulinic acid 3β-caffeate (IC(50) = 0.85 ± 0.1 μM) and to a lesser extent for the flacourtosides A and E (1 and 5, respectively), and scolochinenoside D (IC(50) values ~10 μM). PMID:22439591

  4. Reactivated tectonic boundaries and implications for the reconstruction of southeastern Australia and northern Victoria Land, Antarctica

    SciTech Connect

    Foster, D.A.; Gleadow, A.J.W. )

    1992-03-01

    Rifted continental margins are strongly influenced by the location of zones of preexisting crustal weakness. Apatite fission track thermochronological data indicate that the Paleozoic lithospheric boundary between the Kanmantoo and Lachlan fold belts in western Victoria, Australia, was reactivated during Mesozoic rifting as a transfer fault. To the east of this boundary, 1-2 km of material was denuded during extension, while essentially no denudation took place during rifting to the west. The correlated tectonic boundary within the Bowers terrane of northern Victoria Land, Antarctica, was also reactivated upon rifting. During fragmentation of Gondwana, movement on this zone perpendicular to the direction of rifting probably determined the location of the Tasman Fracture Zone. When Australia and Antarctica are reconstructed along the trace of the Tasman Fracture Zone, the tectonic boundary in Victoria falls into precise alignment with the Bowers terrane.

  5. A framework of boundary collision data aggregation into neighbourhoods.

    PubMed

    Cui, Ge; Wang, Xin; Kwon, Dae-Won

    2015-10-01

    A large portion of the total number of motor collisions can be boundary collisions; therefore, exaggerated or underestimated numbers for boundary collisions aggregated into neighbourhoods may hamper road safety analyses and management. In this paper, we propose a systematic framework for boundary collision aggregation. First, an entropy-based histogram thresholding method is utilized to determine the boundary zone size and identify boundary collisions. Next, the collision density probability distribution is then established, based on the collisions in each neighbourhood. Last, an effective boundary collision aggregation method, called the collision density ratio (CDR), is used to aggregate boundary collisions into neighbourhoods. The proposed framework is applied to collision data in the City of Edmonton for a case study. The experimental results show that the proposed entropy-based histogram thresholding method can identify boundary collision with the high precision and recall, and the proposed CDR method is more effective than the existing methods, the half-to-half ratio method and the one-to-one ratio method, to aggregate boundary collisions into neighbourhoods. PMID:26143631

  6. Reassessment of the Bahamas Fracture Zone

    SciTech Connect

    Ball, M.M. )

    1991-03-01

    The Bahamas Fracture Zone trends northwestward across south Florida and the Western Florida shelf, and it appears to connect with the Gilbertown-Pickens-Pollard portion of the circum-Gulf of Mexico fault system. Along the fracture zone's trend, seismic reflection data reveal normal displacement in the Late Jurassic section of a kilometer, on a down-to-the-west fault, 9 km east of the east end of Destin dome in the Apalachicola basin. This fault was active in Late Jurassic and Early Cretaceous time during the gulf spreading event. The Middle Jurassic Louann Salt thins abruptly to the east across this fault. Toward the southeast, where the fracture zone crosses the Florida peninsula, gravity data have previously been interpreted to indicate coincidence of the Bahamas Fracture Zone with a hinge zone attended by relief on the Mohorovicic discontinuity. This interpretation is an artifact resulting from the use of erroneously low densities for the sedimentary fill of the South Florida basin. The inclusion of a nonexistent negative component for the basin's sedimentary fill necessitated the inclusion of an equally nonexistent positive contribution from relief on the Moho in order to match the observed anomaly. Although northwestward-trending faults do cross south Florida and the Western Florida shelf, the role of the Bahamas Fracture Zone as a boundary between continental and transitional or oceanic crust is insupportable.

  7. Habitable zone dependence on stellar parameter uncertainties

    SciTech Connect

    Kane, Stephen R.

    2014-02-20

    An important property of exoplanetary systems is the extent of the Habitable Zone (HZ), defined as that region where water can exist in a liquid state on the surface of a planet with sufficient atmospheric pressure. Both ground- and space-based observations have revealed a plethora of confirmed exoplanets and exoplanetary candidates, most notably from the Kepler mission using the transit detection technique. Many of these detected planets lie within the predicted HZ of their host star. However, as is the case with the derived properties of the planets themselves, the HZ boundaries depend on how well we understand the host star. Here we quantify the uncertainties of HZ boundaries on the parameter uncertainties of the host star. We examine the distribution of stellar parameter uncertainties from confirmed exoplanet hosts and Kepler candidate hosts and translate these into HZ boundary uncertainties. We apply this to several known systems with an HZ planet to determine the uncertainty in their HZ status.

  8. On the Ekman instability at the core-mantle boundary

    NASA Astrophysics Data System (ADS)

    Chkhetiani, O. G.; Shalimov, S. L.

    2016-05-01

    It is shown that the instability of turbulent flows with Ekman velocity profiles in the vicinity of the core-mantle boundary leads to the formation of horizontally oriented circulating roll structures. The geophysical implications of the presence of such structures in the liquid core are explored, namely, the formation of the hot zones with enhanced conductivity and their influence on geomagnetic reversals.

  9. Investigations of the wall-shearing stress in turbulent boundary layers

    NASA Technical Reports Server (NTRS)

    Ludwieg, Hubert; Tillmann, W

    1950-01-01

    Because of the unsatisfactory state of knowledge concerning the surface shearing stress of boundary layers with pressure gradients, the problem is re-examined. It is found that for general turbulent boundary layers in wall proximity, that is, in the laminar sublayer, in the transition zone and in the part of the completely turbulent zone near the wall, the same universal law applies as for the plate flow.

  10. HREM of general and twist grain boundaries.

    SciTech Connect

    Merkle, K. L.; Thompson, L. J.

    1999-03-10

    The observation of atomic-scale structures of grain boundaries (GBs) via axial illumination HREM has been largely restricted to tilt GBs, due to the requirement that the electron beam be parallel to a low-index zone axis on both sides of the interface. This condition can be fulfilled for all tilt GBs with disorientation about a low-index direction. The information obtained through HREM studies in many materials has brought important insights concerning the atomic-scale structure of such boundaries. However, it is well known that tilt GBs occupy only an infinitesimally small fraction of the 5-dimensional phase space which describes the macroscopic geometry of all GBs. Therefore, although tilt GBs are very important due to their low energy, it would be useful to also study twist GBs and general GBs that contain twist and tilt components.

  11. Spatial periodic boundary condition for MODFLOW.

    PubMed

    Laattoe, Tariq; Post, Vincent E A; Werner, Adrian D

    2014-01-01

    Small-scale hyporheic zone (HZ) models often use a spatial periodic boundary (SPB) pair to simulate an infinite repetition of bedforms. SPB's are common features of commercially available multiphysics modeling packages. MODFLOW's lack of this boundary type has precluded it from being effectively utilized in this area of HZ research. We present a method to implement the SPB in MODFLOW by development of the appropriate block-centered finite-difference expressions. The implementation is analogous to MODFLOW's general head boundary package. The difference is that the terms on the right hand side of the solution equations must be updated with each iteration. Consequently, models that implement the SPB converge best with solvers that perform both inner and outer iterations. The correct functioning of the SPB condition in MODFLOW is verified by two examples. This boundary condition allows users to build HZ-bedform models in MODFLOW, facilitating further research using related codes such as MT3DMS and PHT3D. PMID:23808416

  12. Turbulent boundary layers over nonstationary plane boundaries

    NASA Technical Reports Server (NTRS)

    Roper, A. T.

    1976-01-01

    Methods of predicting integral parameters and skin-friction coefficients of turbulent boundary layers developing over moving-ground-planes are evaluated using test information from three different wind tunnel facilities at the NASA Langley Research Center. These data include test information from the VSTOL tunnel which is presented for the first time. The three methods evaluated were: (1) relative integral parameter method, (2) relative power law method, and (3) modified law of the wall method. Methods (1) and (2) can be used to predict moving-ground-plane shape factors with an expected accuracy of + or - 10%. They may also be used to predict moving-ground-plane displacement and momentum thicknesses with lower expected accuracy. This decrease in accuracy can be traced to the failure of approximations upon which these methods are based to prove universal when compared with VSTOL tunnel test results.

  13. Probabilistic boundary element method

    NASA Technical Reports Server (NTRS)

    Cruse, T. A.; Raveendra, S. T.

    1989-01-01

    The purpose of the Probabilistic Structural Analysis Method (PSAM) project is to develop structural analysis capabilities for the design analysis of advanced space propulsion system hardware. The boundary element method (BEM) is used as the basis of the Probabilistic Advanced Analysis Methods (PADAM) which is discussed. The probabilistic BEM code (PBEM) is used to obtain the structural response and sensitivity results to a set of random variables. As such, PBEM performs analogous to other structural analysis codes such as finite elements in the PSAM system. For linear problems, unlike the finite element method (FEM), the BEM governing equations are written at the boundary of the body only, thus, the method eliminates the need to model the volume of the body. However, for general body force problems, a direct condensation of the governing equations to the boundary of the body is not possible and therefore volume modeling is generally required.

  14. Boundary layer simulator improvement

    NASA Technical Reports Server (NTRS)

    Praharaj, Sarat C.; Schmitz, Craig P.; Nouri, Joseph A.

    1989-01-01

    Boundary Layer Integral Matrix Procedure (BLIMPJ) has been identified by the propulsion community as the rigorous boundary layer program in connection with the existing JANNAF reference programs. The improvements made to BLIMPJ and described herein have potential applications in the design of the future Orbit Transfer Vehicle engines. The turbulence model is validated to include the effects of wall roughness and a way is devised to treat multiple smooth-rough surfaces. A prediction of relaminarization regions is examined as is the combined effects of wall cooling and surface roughness on relaminarization. A turbulence model to represent the effects of constant condensed phase loading is given. A procedure is described for thrust decrement calculation in thick boundary layers by coupling the T-D Kinetics Program and BLIMPJ and a way is provided for thrust loss optimization. Potential experimental studies in rocket nozzles are identified along with the required instrumentation to provide accurate measurements in support of the presented new analytical models.

  15. Road boundary detection

    NASA Technical Reports Server (NTRS)

    Sowers, J.; Mehrotra, R.; Sethi, I. K.

    1989-01-01

    A method for extracting road boundaries using the monochrome image of a visual road scene is presented. The statistical information regarding the intensity levels present in the image along with some geometrical constraints concerning the road are the basics of this approach. Results and advantages of this technique compared to others are discussed. The major advantages of this technique, when compared to others, are its ability to process the image in only one pass, to limit the area searched in the image using only knowledge concerning the road geometry and previous boundary information, and dynamically adjust for inconsistencies in the located boundary information, all of which helps to increase the efficacy of this technique.

  16. Totally thorascopic surgical ablation of persistent AF and long-standing persistent atrial fibrillation using the "Dallas" lesion set.

    PubMed

    Edgerton, James R; Jackman, Warren M; Mahoney, Cecile; Mack, Michael J

    2009-12-01

    Minimally invasive surgery consisting of bipolar radiofrequency pulmonary vein (PV) isolation and limited ganglionated plexus ablation is effective in eliminating atrial fibrillation (AF) in patients with paroxysmal AF but is less effective in those with persistent AF or long-standing persistent AF. The purpose of this study was examine the results of minimally invasive surgery incorporating an additional set of radiofrequency ablation lines replicating a left-sided Cox maze III procedure. Thirty patients with persistent AF (n = 10) or long-standing persistent AF (n = 20) underwent minimally invasive surgery with an extended lesion set and PV isolation for a minimum follow-up of 6 months. Linear lesions were created at the roof line, at the anterior line, and between the roof line and the left atrial appendage. All patients underwent limited ganglionated plexus ablation and left atrial appendage excision as well as PV isolation verification. Block across the roof and anterior lines was confirmed in 29 (96.6%) of the 30 patients. Follow-up included 2-week event monitoring with auto-trigger in 21 patients, pacemaker interrogation in 8, and ECG in 1 who was in AF and refused longer-term monitoring. No operative mortality or major morbidity occurred. At 6 months, 24 (80%) of the 30 patients were free of AF: 15 (75%) with long-standing persistent AF and 9 (90%) with persistent AF. Among the six failures, burden of AF was low: one had 1 episode >15 seconds, two had 4 episodes, one had 6 episodes, one had >50 episodes, and one had AF on ECG and refused further monitoring. Early results of minimally invasive surgery with a new extended linear lesion set suggest increased efficacy over PV isolation and limited ganglionated plexus ablation in patients with persistent AF or long-standing persistent AF. PMID:19959146

  17. Seismic images of a Grenvillian terrane boundary

    USGS Publications Warehouse

    Milkereit, B.; Forsyth, D. A.; Green, A.G.; Davidson, A.; Hanmer, S.; Hutchinson, Deborah R.; Hinze, W. J.; Mereu, R. F.

    1992-01-01

    A series of gently dipping reflection zones extending to mid-crustal depths is recorded by seismic data from Lakes Ontario and Erie. These prominent reflection zones define a broad complex of southeast-dipping ductile thrust faults in the interior of the Grenville orogen. One major reflection zone provides the first image of a proposed Grenvillian suture—the listric boundary zone between allochthonous terranes of the Central Gneiss and Central Metasedimentary belts. Curvilinear bands of reflections that may represent "ramp folds" and "ramp anticlines" that originally formed in a deep crustal-scale duplex abut several faults. Vertical stacking of some curvilinear features suggests coeval or later out-of-sequence faulting of imbricated and folded thrust sheets. Grenvillian structure reflections are overlain by a thin, wedge-shaped package of shallow-dipping reflections that probably originates from sediments deposited in a local half graben developed during a period of post-Grenville extension. This is the first seismic evidence for such extension in this region, which could have occurred during terminal collapse of the Grenville orogen, or could have marked the beginning of pre-Appalachian continental rifting.

  18. Fault damage zones

    NASA Astrophysics Data System (ADS)

    Kim, Young-Seog; Peacock, David C. P.; Sanderson, David J.

    2004-03-01

    Damage zones show very similar geometries across a wide range of scales and fault types, including strike-slip, normal and thrust faults. We use a geometric classification of damage zones into tip-, wall-, and linking-damage zones, based on their location around faults. These classes can be sub-divided in terms of fault and fracture patterns within the damage zone. A variety of damage zone structures can occur at mode II tips of strike-slip faults, including wing cracks, horsetail fractures, antithetic faults, and synthetic branch faults. Wall damage zones result from the propagation of mode II and mode III fault tips through a rock, or from damage associated with the increase in slip on a fault. Wall damage zone structures include extension fractures, antithetic faults, synthetic faults, and rotated blocks with associated triangular openings. The damage formed at the mode III tips of strike-slip faults (e.g. observed in cliff sections) are classified as wall damage zones, because the damage zone structures are distributed along a fault trace in map view. Mixed-mode tips are likely to show characteristics of both mode II and mode III tips. Linking damage zones are developed at steps between two sub-parallel faults, and the structures developed depend on whether the step is extensional or contractional. Extension fractures and pull-aparts typically develop in extensional steps, whilst solution seams, antithetic faults and synthetic faults commonly develop in contractional steps. Rotated blocks, isolated lenses or strike-slip duplexes may occur in both extensional and contractional steps. Damage zone geometries and structures are strongly controlled by the location around a fault, the slip mode at a fault tip, and by the evolutionary stage of the fault. Although other factors control the nature of damage zones (e.g. lithology, rheology and stress system), the three-dimensional fault geometry and slip mode at each tip must be considered to gain an understanding of

  19. USACE DIVISION AND DISTRICT BOUNDARIES

    EPA Science Inventory

    The USACE Division and District Boundary data contains the delination of Corps Division and District boundaries. District and Division Boundaries are based on the US political and watershed boundaries. In the mid 1990's, WES created the file by digitizing the 1984 Civil Wor...

  20. Lithosphere-asthenosphere boundary: Where and why?

    NASA Astrophysics Data System (ADS)

    Aryasova, Olga; Khazan, Yakov

    2015-04-01

    A necessary condition of the lithosphere steady state is that the convective boundary layer (CBL) accommodating a transition from the lithosphere to the convecting mantle is on the verge of instability. The common practice of solving the stationary heat equation with boundary conditions (temperature and heat flow) imposed on the surface provides a solution which does not necessarily satisfy the marginal stability condition (MSC) of the CBL and therefore does not necessarily describe a valid steady state. We suggest the approach to the thermal modeling that uses the MSC instead of the heat flow boundary condition, which guarantees that the solution describes the steady-state lithosphere. In addition, in contrast to the commonly used approach, the MSC-based solution only weakly depends on the uncertainty of the crustal heat production in the sense that any two steady-state geotherms corresponding to different crustal heat production, but the same potential temperature and lithosphere structure, converge at depth. We demonstrate that if there is no obstacle to the mantle convection like chemical boundary layer (ChBL) comprising the crust and the layer of depleted rock then the lithosphere base occurs at the rheological depth, Hrh, which is of 70 to 50 km under the potential temperature of 1300 to 1350oC. This situation is characteristic of the mantle beneath the old oceanic crust areas far from disturbed regions, with the heat flow and the seafloor depth depending only on the potential temperature,Tp. An absence of noticeable distinctions between the heat flows in different oceanic basins suggests a global constancy of the potential temperature Tp at least in suboceanic mantle. Beneath continents, the ChBL thickness, Hdepl, exceeds Hrh even in Phanerozoic regions and, all the more so, in Precambrian ones. Therefore, in the subcontinental mantle the lithosphere is the same as the chemical boundary layer and the CBL is immediately adjacent to the lithosphere base. We

  1. Seismotectonics of the southern boundary of Anatolia, Eastern Mediterranean region: subduction, collision, and arc jumping

    SciTech Connect

    Rotstein, Y.; Kafka, A.L.

    1982-09-10

    The pattern of seismicity and fault plane solutions of earthquakes are used to outline the tectonic features of the southern boundary of Anatolia in the eastern Mediterranean and southeastern Turkey. The results of this study show that this boundary is composed of two distinct parts. One, in southeastern Turkey and Syria, is a wide and complex zone of continental collision. The other, in the Levantine basin of the eastern Mediterranean, is a zone of oceanic subduction. In the region of continental collision three zones of seismicity are observed. Most of the seismic activity in this region follows the Bitlis zone and is associated with a zone of thrusting and mountain building. This appears to be the zone of most active deformation and plate consumption in the plate boundary region between Arabia and Turkey. A less active zone of seismicity to the north of the Bitlis zone is interpreted to have been more active in the past whereas another active zone of seismicity to the south is interpreted to be a zone which may be more active in the future as the main zone of plate consumption jumps to the south. In the subduction zone of the eastern Mediterranean the depth of the subducted slab and the rate of seismicity generally increease from east to west. The zone of present-day convergence between Africa and Turkey in the Levantine basin can be best outlined by the northern edge of the Mediterranean ridge. Deep seismic activity near the Gulf of Antalya is associated with a detached subducted slab north of the Anaximander Mountains that is distinctly different from the seismic trend which is associated with present-day active subduction. Most of the focal mechanisms of the earthquakes along the entire southern boundary of Anatolia indicate that N to NNW thrusting is the dominant mode of seismic deformation.

  2. Anaerobic treatment of strong sewage by a two stage system of AF and UASB reactors.

    PubMed

    Sawajneh, Z; Al-Omari, A; Halalsheh, M

    2010-01-01

    An anaerobic treatment system that consists of an Anaerobic Filter (AF) and an Upflow Anaerobic Sludge Blanket (UASB) in series was built and operated to investigate its performance in treating strong domestic wastewater with high suspended solids fraction under Jordan's ambient temperatures of 25 degrees C for summer and 18 degrees C for winter. The system was operated from September 2003 until early April 2004. The system was operated at a Hydraulic Retention Time (HRT) of 4 hours for the first stage AF and 8 hours for the second stage UASB. Average COD(t) and COD(ss) removal efficiencies of the AF/UASB were 58% and 81% respectively for the operation period. The results showed that the first stage AF was effective in removing suspended solids. In addition, hydrolysis, acidification and methanogenesis took place in the first stage AF which was advantageous to the second stage UASB. It was concluded that the AF/UASB system is effective in treating strong domestic wastewater with high suspended solids content under Jordan's ambient temperatures. PMID:20418638

  3. PUF60: a novel U2AF65-related splicing activity.

    PubMed Central

    Page-McCaw, P S; Amonlirdviman, K; Sharp, P A

    1999-01-01

    We have identified a new pyrimidine-tract binding factor, PUF, that is required, together with U2AF, for efficient reconstitution of RNA splicing in vitro. The activity has been purified and consists of two proteins, PUF60 and the previously described splicing factor p54. p54 and PUF60 form a stable complex in vitro when cotranslated in a reaction mixture. PUF activity, in conjunction with U2AF, facilitates the association of U2 snRNP with the pre-mRNA. This reaction is dependent upon the presence of the large subunit of U2AF, U2AF65, but not the small subunit U2AF35. PUF60 is homologous to both U2AF65 and the yeast splicing factor Mud2p. The C-terminal domain of PUF60, the PUMP domain, is distantly related to the RNA-recognition motif domain, and is probably important in protein-protein interactions. PMID:10606266

  4. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    PubMed

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity. PMID:27372134

  5. Dynamics of diffuse oceanic plate boundaries: insensitivity to rheology

    NASA Astrophysics Data System (ADS)

    Zatman, Stephen; Gordon, Richard G.; Mutnuri, Kartik

    2005-07-01

    Diffuse plate boundaries, which are zones of deformation hundreds to thousands of kilometres wide, occur in both continental and oceanic lithosphere. Here, we build on our prior work in which we described analytic approximations to simple dynamical models that assume that the vertically averaged viscous force resisting deformation in diffuse oceanic plate boundaries (DOPBs) is described by either a linear Newtonian viscous rheology or a yield-stress (high-exponent power-law) rheology. An important observation is that the poles of relative rotation of adjacent component plates tend to lie in the diffuse plate boundary that separates them. A key cause of this tendency is that a faster spin is needed to balance a component of torque through the middle of a diffuse plate boundary than to balance an equal component of torque lying 90° from the middle of the diffuse boundary. The strength of that tendency depends on rheology, however, with the tendency being stronger for a yield-stress rheology than for a Newtonian viscous rheology. For the special case of the pole of rotation lying outside of and along the strike of the boundary, these large differences can be simply explained in terms of the distribution of boundary-perpendicular normal forces acting across the boundary. In the Newtonian case, the distribution of forces has an along-strike gradient that can balance a component of torque about the middle of the boundary, while in the yield-stress case, the distribution of forces has zero along-strike gradient and cannot balance a component of torque about the middle of the diffuse plate boundary. To expand our analysis to intermediate power laws of geophysical interest (i.e. power-law exponents of 3 to 30), as well as to investigate more thoroughly the behaviour for a high-exponent power law, we numerically integrate the force distribution to obtain the torques. Results for intermediate power laws resemble the yield-stress rheology much more than they resemble the

  6. RCRA TSD BOUNDARIES

    EPA Science Inventory

    This is a shapefile of RCRA Treatment, Storage, and Disposal facility boundaries developed by PRC Environmental Management, Inc (PRC) per a Work Assignment from the U.S. EPA under the Resource Conservation and Recovery Act (RCRA) Enforcement, Permitting, and Assistance (REPA) Con...

  7. 2000 CENSUS BLOCK BOUNDARIES

    EPA Science Inventory

    This data set is a polygon shapefile of the boundaries of Census Blocks in New England derived from U.S. Census Bureau 2000 TIGER/Line data. Numerous attributes pertaining to population are included. TIGER, TIGER/Line, and Census TIGER are registered trademarks of the Bureau o...

  8. Saturn's Magnetospheric Boundaries

    NASA Astrophysics Data System (ADS)

    Kurth, W. S.; Gurnett, D. A.; Hospodarsky, G. B.; Dougherty, M. K.; Arridge, C. S.; Achilleos, N. A.; Andre, N.; Crary, F. J.; McAndrews, H. J.; Szego, K.; Rymer, A. M.; Krimigis, S. M.; Mitchell, D. G.; Krupp, N.; Hamilton, D. C.; Hansen, K. C.

    2005-12-01

    Cassini has now been in orbit at Saturn for more than a year, making more than 12 passes through Saturn's magnetosphere. While the apoapses of these orbits have so far remained clustered near dawn and the inclinations have been mostly below about 20 degrees, progress has been made in mapping and understanding various magnetospheric boundaries. For example, initial modeling of the bow shock and magnetopause by Hendricks et al. [GRL, 32, 2005] suggest the magnetosphere is somewhat more inflated than thought from Pioneer- and Voyager-based models. Of perhaps even more interest are internal boundaries within the magnetosphere. These boundaries separate various magnetospheric regions and are less rigorously defined than the external boundaries. In fact, a number of authors have identified different regions based on particular sets of measurements; we review some of these and attempt to integrate these into a scheme of general utility, realizing that ongoing work on interpretation of existing observations and high inclination orbits to come will likely modify any such scheme we may devise this early in Cassini's tour.

  9. The atmospheric boundary layer

    SciTech Connect

    Garratt, J.R.

    1992-01-01

    This book is aimed at researchers in the atmospheric and associated sciences who require a moderately advanced text on the Atmospheric Boundary Layer (ABL) in which the many links between turbulence, air-surface transfer, boundary-layer structure and dynamics, and numerical modeling are discussed and elaborated upon. Chapter 1 serves as an introduction, with Chapters 2 and 3 dealing with the development of mean and turbulence equations, and the many scaling laws and theories that are the cornerstone of any serious ABL treatment. Modelling of the ABL is crucially dependent for its realism on the surface boundary conditions, and Chapters 4 and 5 deal with aerodynamic and energy considerations, with attention to both dry and wet land surfaces and the sea. The structure of the clear-sky, thermally stratified ABL is treated in Chapter 6, including the convective and stable cases over homogeneous land, the marine ABL and the internal boundary layer at the coastline. Chapter 7 then extends the discussion to the cloudy ABL. This is seen as particularly relevant since the extensive stratocumulus regions over the sub-tropical oceans and stratus regions over the Arctic are now identified as key players in the climate system. Finally, Chapters 8 and 9 bring much of the book's material together in a discussion of appropriate ABL and surface parameterization schemes for the general circulation models of the atmosphere that are being used for climate simulation.

  10. FIVE-DIGIT ZIP CODE BOUNDARIES FOR THE CONTERMINOUS UNITED STATES

    EPA Science Inventory

    The Five-Digit ZIP (Zoning Improvement Plan) Code boundary layer (zip5) is derived from the Geographic Data Technology (GDT), Inc. ZIP Boundary and Inventory Files (v. 5.0) and stored in the EPA Spatial Data Library System (ESDLS). This layer contains data for the conterminous U...

  11. AF9 promotes hESC neural differentiation through recruiting TET2 to neurodevelopmental gene loci for methylcytosine hydroxylation

    PubMed Central

    Qiao, Yunbo; Wang, Xiongjun; Wang, Ran; Li, Yuanyuan; Yu, Fang; Yang, Xianfa; Song, Lu; Xu, Guoliang; Chin, Y Eugene; Jing, Naihe

    2015-01-01

    AF9 mutations have been implicated in human neurodevelopmental diseases and murine Af9 mediates histone methylation during cortical neuron generation. However, AF9 function and related mechanisms in human neurodevelopment remain unknown. Here we show that AF9 is necessary and sufficient for human embryonic stem cell (hESC) neural differentiation and neurodevelopmental gene activation. The 5-methylcytosine (5mC) dioxygenase TET2, which was identified in an AF9-associated protein complex, physically interacted with AF9. Both AF9 and TET2 co-localized in 5-hydroxymethylcytosine (5hmC)-positive hESC-derived neurons and were required for appropriate hESC neural differentiation. Upon binding to AAC-containing motifs, AF9 recruited TET2 to occupy the common neurodevelopmental gene loci to direct 5mC-to-5hmC conversion, which was followed by sequential activation of neural target genes and hESC neural commitment. These findings define an AF9–TET2 regulatory complex for modulating human neural development and reveal a novel mechanism by which the AF9 recognition specificity and TET2 hydroxylation activity cooperate to control neurodevelopmental gene activation. PMID:27462416

  12. Computation of grain boundary stiffness and mobility from boundary fluctuations.

    SciTech Connect

    Hoyt, Jeffrey John; Foiles, Stephen Martin

    2005-06-01

    Grain boundary stiffness and mobility determine the kinetics of curvature-driven grain growth. Here the stiffness and mobility are computed using an analysis of fluctuations in the grain boundary position during molecular dynamics simulations. This work represents the first determination of grain boundary stiffness for a realistic three-dimensional system. The results indicate that the boundary stiffness for a given boundary plane has a strong dependence on the direction of the boundary distortion. The mobility deduced is comparable with that determined in previous computer simulation studies. The advantages and limitations of the fluctuation approach are discussed.

  13. Normal anatomic relationship between urethral sphincter complex and zones of prostrate in young Chinese males on MRI

    PubMed Central

    Wang, Xiangdong; Liu, Tieyan; Zhao, Jing; Sun, Jingyi; Chen, Yuefeng; Sun, Pengyu; Wang, Xuesong; Liu, Sheng

    2015-01-01

    Objective In this research, the normal anatomic relationship between urethral sphincter complex and zones of prostrate in young Chinese males has been studied. Methods: The sagittal, coronal, and axial T2-weighted non-fat suppressed fast spin-echo images of pelvic cavities of 86 Chinese young males were studied. Result: Urethral sphincter complex threaded through the prostate and divided it into 2 parts: transition zone (TZ), periurethral glands internal to the urethral sphincter and peripheral zone (PZ), central zone (CZ), anterior fibromuscular stroma (AFS) zone external to the urethral sphincter. The length of urethral striated sphincter is 12.26-20.94 mm (mean 16.59 mm) at membranous urethra. Conclusions: In this paper, we summarized the normal anatomic relationship between urethral sphincter complex and zones of prostrate in young Chinese males with no urinary control problems. PMID:26629244

  14. Influence of melt motion on the shape of molten zone in the FZ crystal growth process

    NASA Astrophysics Data System (ADS)

    Dadzis, K.; Muiznieks, A.; Rudevics, A.; Riemann, H.; Ludge, A.

    2007-06-01

    In numerical simulations of the floating-zone crystal growth process, the shape of phase boundaries is unknown beforehand and must be obtained as a part of the solution. One of the factors, which may influence the shape of phase boundaries significantly, is convective heat transfer in the molten zone. The present paper offers an analysis based on mathematical modelling of the influence of the melt motion on the shape of phase boundaries by investigating a specific 2" floating zone growth system and compares the modelling results with experiment. A needle-eye inductor is used in the growth system leading to curved boundaries of the molten zone and to strong high-frequency electromagnetic forces in the melt. The influence of the melt motion on the crystallization interface is also estimated analytically. Figs 12, Refs 8.

  15. Statin Therapy for the Prevention of Atrial Fibrillation Trial (SToP AF trial)

    PubMed Central

    Negi, Smita; Shukrullah, Irfan; Veledar, Emir; Bloom, Heather L.; Jones, Dean P.; Dudley, Samuel C.

    2010-01-01

    Background Inflammation and oxidative stress are associated with atrial fibrillation (AF). Statins have antioxidant and anti-inflammatory properties. We tested if atorvastatin reduced AF recurrence after DC cardioversion (CV) by modifying systemic oxidative stress and inflammation. (NCT00252967) Methods and Results In a randomized, double-blinded, placebo-controlled trial, patients with atrial fibrillation/flutter (AF) were randomized to receive either atorvastatin 80 mg (n=33) or placebo (n=31) before CV. Treatment was continued for 12 months or until AF recurred. Serum oxidative stress markers (ratios of oxidized to reduced glutathione and cysteine, derivatives of reactive oxygen species, isoprostanes) and inflammatory markers [ high sensitivity C- reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-1β(IL-1β), tumor necrosis factor-α (TNFα)] were measured at baseline and on follow-up. AF recurred in 22 (66.7%) of atorvastatin and 26 (83.9%) of placebo group (p=0.2). The adjusted hazard ratio of having recurrence on atorvastatin versus on placebo was 0.99 (95% CI: 0.98-1.01, p=0.3). There was no significant difference in the time to recurrence using Kaplan-Meier survival estimates (median (IR): 29 (2-145) days vs. 22 (7-70) days, p=0.9). While no significant effect was seen on oxidative stress, 2 of 4 inflammatory markers, IL-6 (adjusted OR: 0.59, 95% CI: 0.35-0.97, p= 0.04) and hs-CRP (adjusted OR: 0.59, 95% CI: 0.37-0.95, p=0.03) were significantly lowered with atorvastatin. Cholesterol levels significantly decreased with atorvastatin (p=0.03). Conclusions High dose atorvastatin did not reduce the recurrence of AF after CV. It reduced selective markers of inflammation without affecting systemic oxidative stress. Failure of atorvastatin to prevent AF recurrence may be due to its failure to affect oxidative stress. PMID:20946227

  16. Natalizumab-induced POU2AF1/Spi-B upregulation

    PubMed Central

    Meira, Maria; Sievers, Claudia; Hoffmann, Francine; Haghikia, Aiden; Rasenack, Maria; Décard, Bernhard F.; Kuhle, Jens; Derfuss, Tobias; Kappos, Ludwig

    2016-01-01

    Objectives: To assess messenger RNA (mRNA) expression of POU2AF1 and Spi-B and their potential regulatory microRNAs (miRNAs) in natalizumab-treated patients with multiple sclerosis and in therapy-associated progressive multifocal leukoencephalopathy (PML). Methods: Expression of POU2AF1/Spi-B was analyzed by using real-time reverse transcription PCR assays on isolated B/CD8+ T lymphocytes and peripheral blood mononuclear cells (PBMCs) from cohorts of untreated and natalizumab-treated patients with and without PML. Longitudinal expression analysis was performed on CD4+, CD8+ T and B cells from 14 patients who interrupted natalizumab therapy for 8 weeks. The miRNA profiling was conducted in PBMCs from 5 untreated and 5 natalizumab-treated patients using low-density arrays followed by validation with single miRNAs assays in untreated and natalizumab-treated patients. Results: POU2AF1 and Spi-B mRNAs were upregulated in B and CD8+ T cells from natalizumab-treated patients, which was validated in PBMCs from different cohorts of natalizumab-treated patients with and without PML, with a noteworthy higher expression of Spi-B in patients with PML. In contrast, downregulation of POU2AF1/Spi-B expression was measured in B and CD8+ T cells after natalizumab discontinuation. Seventeen differentially expressed miRNAs including miR-10b, a regulator of POU2AF1 mRNA, were identified in long-term natalizumab-treated patients compared with untreated ones. Conclusions: Upregulation of POU2AF1 and Spi-B, known transactivators of the JC virus, the causative agent for PML, and its association with occurrence of PML in natalizumab-treated patients, corroborates POU2AF1/Spi-B as potential biomarkers for PML risk, which merits further evaluation. PMID:27088119

  17. Sound Radiation from a Turbulent Boundary Layer

    NASA Technical Reports Server (NTRS)

    Laufer, J.

    1961-01-01

    If the restriction of incompressibility in the turbulence problem is relaxed, the phenomenon of energy radiation in the form of sound from the turbulent zone arises. In order to calculate this radiated energy, it is shown that new statistical quantities, such as time-space correlation tensors, have to be known within the turbulent zone in addition to the conventional quantities. For the particular case of the turbulent boundary layer, indications are that the intensity of radiation becomes significant only in supersonic flows. Under these conditions, the recent work of Phillips is examined together with some experimental findings of the author. It is shown that the qualitative features of the radiation field (intensity, directionality) as predicted by the theory are consistent with the measurements; however, even for the highest Mach number flow, some of the assumptions of the asymptotic theory are not yet satisfied in the experiments. Finally, the question of turbulence damping due to radiation is discussed, with the result that in the Mach number range covered by the experiments, the energy lost from the boundary layer due to radiation is a small percentage of the work done by the wall shearing stresses.

  18. Microgravity silicon zoning investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.; Gill, G. L., Jr.

    1983-01-01

    A resistance heated zoner, suitable for early zoning experiments with silicon, was designed and put into operation. The initial power usage and size was designed for an shown to be compatible with payload carriers contemplated for the Shuttle. This equipment will be used in the definition and development of flight experiments and apparatus for float zoning silicon and other materials in microgravity.

  19. Float Zone Workshop

    NASA Technical Reports Server (NTRS)

    Naumann, R. J.

    1980-01-01

    A summary of the Analytical Float Zone Experiment System (AFZES) concept is presented. The types of experiments considered for such a facility are discussed. Reports from various industrial producers and users of float zone material are presented. Special emphasis is placed on state-of-the-art developments in low gravity manufacturing and their applications to space processing.

  20. Investigating Aquatic Dead Zones

    ERIC Educational Resources Information Center

    Testa, Jeremy; Gurbisz, Cassie; Murray, Laura; Gray, William; Bosch, Jennifer; Burrell, Chris; Kemp, Michael

    2010-01-01

    This article features two engaging high school activities that include current scientific information, data, and authentic case studies. The activities address the physical, biological, and chemical processes that are associated with oxygen-depleted areas, or "dead zones," in aquatic systems. Students can explore these dead zones through both…

  1. Coastal zone management

    NASA Technical Reports Server (NTRS)

    Tilton, E. L., III

    1975-01-01

    A panel of federal and state representatives concerned with coastal zone affairs discussed their problems in this area. In addition, several demonstrations of the application of remote sensing technology to coastal zone management were described. These demonstrations were performed by several agencies in a variety of geographical areas.

  2. Microstructures and microhardness at fusion boundary of 316 stainless steel/Inconel 182 dissimilar welding

    SciTech Connect

    Wang, Wei; Lu, Yonghao; Ding, Xianfei; Shoji, Tetsuo

    2015-09-15

    Microstructures and microhardness at fusion boundary of a weld joint were investigated in a 316 stainless steel/Inconel 182 dissimilar weldment. The results showed that there were two alternately distributed typical fusion boundaries, a narrow random boundary (possessed 15% in length) with a clear sharp interface and an epitaxial fusion one with (100){sub BM}//(100){sub WM} at the joint interface. The composition transition, microstructure and hardness across the fusion boundary strongly depended on the type of the fusion boundary. For the random boundary, there was a clear sharp interface and the composition transition with a width of 100 μm took place symmetrically across the grain boundary. For the epitaxial fusion one, however, there were Type-I and Type-II grain boundaries perpendicular and parallel to the epitaxial fusion boundary, respectively. The composition transition took place in the Inconel 182 weld side. Σ3 boundaries in the HAZ of 316SS side and Σ5 grain boundaries in weld metal were usually observed, despite the type of fusion boundary, however the former was much more in epitaxial fusion boundary. Microhardness was continuously decreased across the random fusion boundary from the side of Inconel 182 to 316SS, but a hardening phenomenon appeared in the epitaxial fusion boundary zone because of its fine cellular microstructure. - Highlights: • Two typical fusion boundaries alternately distributed in the fusion interface • The microstructure, composition and hardness across fusion boundary depended on its type. • Different regions in welded joint have different special CSL value boundaries. • Hardening phenomenon only appeared in the epitaxial fusion boundary.

  3. The structure and evolution of boundary layers in stratified convection

    NASA Astrophysics Data System (ADS)

    Anders, Evan H.; Brown, Benjamin; Brandenburg, Axel; Rast, Mark

    2016-05-01

    Solar convection is highly stratified, and the density in the Sun increases by many orders of magnitude from the photosphere to the base of the convection zone. The photosphere is an important boundary layer, and interactions between the surface convection and deep convection may lie at the root of the solar convection conundrum, where observed large-scale velocities are much lower than predicted by full numerical simulations. Here, we study the structure and time evolution of boundary layers in numerical stratified convection. We study fully compressible convection within plane-parallel layers using the Dedalus pseudospectral framework. Within the context of polytropic stratification, we study flows from low (1e-3) to moderately high (0.1) Mach number, and at moderate to high Rayleigh number to study both laminar and turbulent convective transport. We aim to characterize the thickness and time variation of velocity and thermal (entropy) boundary layers at the top and bottom boundaries of the domain.

  4. Boundary layer simulator improvement

    NASA Technical Reports Server (NTRS)

    Praharaj, S. C.; Schmitz, C.; Frost, C.; Engel, C. D.; Fuller, C. E.; Bender, R. L.; Pond, J.

    1984-01-01

    High chamber pressure expander cycles proposed for orbit transfer vehicles depend primarily on the heat energy transmitted from the combustion products through the thrust wall chamber wall. The heat transfer to the nozzle wall is affected by such variables as wall roughness, relamarization, and the presence of particles in the flow. Motor performance loss for these nozzles with thick boundary layers is inaccurate using the existing procedure coded BLIMPJ. Modifications and innovations to the code are examined. Updated routines are listed.

  5. Boundary transfer matrices and boundary quantum KZ equations

    SciTech Connect

    Vlaar, Bart

    2015-07-15

    A simple relation between inhomogeneous transfer matrices and boundary quantum Knizhnik-Zamolodchikov (KZ) equations is exhibited for quantum integrable systems with reflecting boundary conditions, analogous to an observation by Gaudin for periodic systems. Thus, the boundary quantum KZ equations receive a new motivation. We also derive the commutativity of Sklyanin’s boundary transfer matrices by merely imposing appropriate reflection equations, in particular without using the conditions of crossing symmetry and unitarity of the R-matrix.

  6. Overriding Plate Controls on Subduction Zone Evolution

    NASA Astrophysics Data System (ADS)

    Sharples, W. K.; Jadamec, M. A.; Moresi, L. N.; Capitanio, F. A.

    2014-12-01

    Seismic data, rock deformation experiments, and geochemical studies indicate variability in the thickness, buoyancy, and strength of the lithosphere at plate boundaries. However, geodynamic models of subduction commonly either omit an overriding plate or do not investigate role of the variation in overriding plate properties on the subduction evolution. We present time-dependent numerical models of subduction that vary the overriding plate thickness, strength, and density and allow for a plate interface that evolves with time via an anisotropic brittle failure rheology. We examine the emergence of (a) asymmetric versus symmetric subduction, (b) trench retreat versus advance, (c) subduction zone geometry, (d) slab stagnation versus penetration into the lower mantle, and (e) flat slab subduction. The majority of the models result in sustained asymmetric subduction. The models demonstrate that trench retreat is correlated with a thin overriding plate, whereas, trench advance is correlated with a thick and/or strong overriding plate. Slab dip, measured at a depth below the plate boundary interface, has a negative correlation with an increase in overriding plate thickness. Overriding plate thickness exerts a first order control over slab penetration into the lower mantle, with penetration most commonly occurring in models with a thick overriding plate. Periods of flat slab subduction occur with thick, strong overriding plates producing strong plate boundary interface coupling. The results provide insight into how the overriding plate plays a role in establishing advancing and retreating subduction, as well as providing an explanation for the variation of slab geometry observed in subduction zones on Earth.

  7. Structure of the upper mantle boundaries in North Eurasia and their origin

    NASA Astrophysics Data System (ADS)

    Pavlenkova, Ninel

    2016-04-01

    The seismic profiling with Peace Nuclear Explosions (PNE) shows unusual velocity stratification of the North Eurasia upper mantle. The asthenosphere is not traced as a low velocity layer, on the contrary, the 10-20 km thick velocity inversion zones are revealed at depth around 100 km. Several seismic boundaries are traced along the profiles. The most regular boundaries are at depths of 80-120 km (N boundary or 80 boundary) and 200-250 km (L boundary). The reflections from these boundaries are complicate many phase groups which may be formed by the reflective zones with alternating of the high- and low-velocity layers. These boundaries and the low velocity layers were unexpected results of the seismic profiling because it appeared unrealistic to find the regular and strong velocity contrasts in the upper mantle whose velocities are insensitive to the material composition, and no phase transitions were revealed at the boundary depths. The interpretation of the low velocity layers at depth around 100 km as zones of partial melting is invalid in the old platform areas where the melting ("thermal asthenosphere") was supposed at the depths of 250-300 km. The revealed boundaries might appear as the physical boundaries marked by the sharp changes in the different physical or mechanical properties of the material (porosity, permeability, fissuring and others). The increase or decrease in porosity is invariably followed by the change in the fluid content, which can initiate the different physicochemical transformations of the material, such as the new degrees of metamorphism, and initiate partial melting and mobility of the material at relatively low temperature. The laboratory study of the fluids transportation through the mantle rocks at the high pressure and temperature confirm such transformation. The matter flow along these weak zones may assist the formation of the anisotropic high velocity intermediate layers. Comparison of the seismic data with other geophysical data

  8. Geophysical Limitations on the Habitable Zone

    NASA Astrophysics Data System (ADS)

    Noack, L.; Van Hoolst, T.

    2015-10-01

    Planets are typically classified as potentially life-bearing planets (i.e. habitable planets) if they are rocky planets and if a liquid (e.g. water) could exist at the surface. The latter depends on several factors, like for example the amount of available solar energy, greenhouse effects in the atmosphere and an efficient CO2-cycle. However, the definition of the habitable zone should be updated to include possible geophy-sical constraints, that could potentially influence the CO2-cycle. Planets like Mars without plate tectonics and no or only limited volcanic events can only be considered to be habitable at the inner boundary of the habitable zone, since the greenhouse effect needed to ensure liquid surface water farther away from the sun is strongly reduced. We investigate how these geophysical processes depend on the mass and interior structure of terrestrial planets. We find that plate tectonics, if it occurs, always leads to sufficient volcanic outgassing and therefore greenhouse effect needed for the outer boundary of the habitable zone (several tens of bar CO2). One-plate planets, however, may suffer strong volcanic limitations if their mass and/or iron content exceeds a critical value, reducing their possible surface habitability.

  9. Inclusions and Microstructure of Ce-Added Weld Metal Coarse Grain Heat-Affected Zone in Twin-Wire Submerged-Arc Welding

    NASA Astrophysics Data System (ADS)

    Yu, S. F.; Yan, N.; Chen, Y.

    2016-04-01

    In high heat-input multi-pass twin-wire submerged-arc welding, weld metal of previous pass will be affected by the heat input of subsequent one and form coarse-grained heat-affected zone (CGHAZ). This study focused on the effects of welding thermal cycle on the inclusions and microstructure of Ce-alloyed weld metal CGHAZ. According to the study of inclusions and microstructure of weld metal CGHAZ, it was found that the composition and type of the inclusions did not change under the effect of welding thermal cycle. Although the inclusions were coarsened slightly, the promoting ability to acicular ferrite (AF) was not deprived after thermal cycling. There are three types of AF in weld metal CGHAZ, which include oxy-sulfides of Ce inclusions-promoted AF, home-position-precipitated AF, and sympathetic AF. Results showed more than 80% of microstructure was AF, which greatly benefited the mechanical properties of weld metal CGHAZ, even though granular bainite and M-A constituents were generated.

  10. Inclusions and Microstructure of Ce-Added Weld Metal Coarse Grain Heat-Affected Zone in Twin-Wire Submerged-Arc Welding

    NASA Astrophysics Data System (ADS)

    Yu, S. F.; Yan, N.; Chen, Y.

    2016-06-01

    In high heat-input multi-pass twin-wire submerged-arc welding, weld metal of previous pass will be affected by the heat input of subsequent one and form coarse-grained heat-affected zone (CGHAZ). This study focused on the effects of welding thermal cycle on the inclusions and microstructure of Ce-alloyed weld metal CGHAZ. According to the study of inclusions and microstructure of weld metal CGHAZ, it was found that the composition and type of the inclusions did not change under the effect of welding thermal cycle. Although the inclusions were coarsened slightly, the promoting ability to acicular ferrite (AF) was not deprived after thermal cycling. There are three types of AF in weld metal CGHAZ, which include oxy-sulfides of Ce inclusions-promoted AF, home-position-precipitated AF, and sympathetic AF. Results showed more than 80% of microstructure was AF, which greatly benefited the mechanical properties of weld metal CGHAZ, even though granular bainite and M-A constituents were generated.

  11. Low strain, long life creep fatigue of AF2-1DA and INCO 718

    SciTech Connect

    Thakker, A.B.; Cowles, B.A.

    1983-04-01

    Two aircraft turbine disk alloys, GATORIZED AF2-DA and INCO 718 were evaluated for their low strain long life creep-fatigue behavior. Static (tensile and creep rupture) and cyclic properties of both alloys were characterized. The cntrolled strain LCF tests were conducted at 760 C (1400 F) and 649 C (1200 F) for AF2-1DA and INCO 718, respectively. Hold times were varied for tensile, compressive and tensile/compressive strain dwell (relaxation) tests. Stress (creep) hold behavior of AF2-1DA was also evaluated. Generally, INCO 718 exhibited more pronounced reduction in cyclic life due to hold than AF2-1DA. The percent reduction in life for both alloys for strain dwell tests was greater at low strain ranges (longer life regime). Changing hold time from 0 to 0.5, 2.0 and 15.0 min. resulted in corresponding reductions in life. The continuous cycle and cyclic/dwell initiation failure mechanism was predominantly transgranular for AF2-1DA and intergranular for INCO 718.

  12. A simple web-based tool to compare freshwater fish data collected using AFS standard methods

    USGS Publications Warehouse

    Bonar, Scott A.; Mercado-Silva, Norman; Rahr, Matt; Torrey, Yuta T.; Cate, Averill, Jr.

    2016-01-01

    The American Fisheries Society (AFS) recently published Standard Methods for Sampling North American Freshwater Fishes. Enlisting the expertise of 284 scientists from 107 organizations throughout Canada, Mexico, and the United States, this text was developed to facilitate comparisons of fish data across regions or time. Here we describe a user-friendly web tool that automates among-sample comparisons in individual fish condition, population length-frequency distributions, and catch per unit effort (CPUE) data collected using AFS standard methods. Currently, the web tool (1) provides instantaneous summaries of almost 4,000 data sets of condition, length frequency, and CPUE of common freshwater fishes collected using standard gears in 43 states and provinces; (2) is easily appended with new standardized field data to update subsequent queries and summaries; (3) compares fish data from a particular water body with continent, ecoregion, and state data summaries; and (4) provides additional information about AFS standard fish sampling including benefits, ongoing validation studies, and opportunities to comment on specific methods. The web tool—programmed in a PHP-based Drupal framework—was supported by several AFS Sections, agencies, and universities and is freely available from the AFS website and fisheriesstandardsampling.org. With widespread use, the online tool could become an important resource for fisheries biologists.

  13. GLA-AF, an emulsion-free vaccine adjuvant for pandemic influenza.

    PubMed

    Clegg, Christopher H; Roque, Richard; Perrone, Lucy A; Rininger, Joseph A; Bowen, Richard; Reed, Steven G

    2014-01-01

    The ongoing threat from Influenza necessitates the development of new vaccine and adjuvant technologies that can maximize vaccine immunogenicity, shorten production cycles, and increase global vaccine supply. Currently, the most successful adjuvants for Influenza vaccines are squalene-based oil-in-water emulsions. These adjuvants enhance seroprotective antibody titers to homologous and heterologous strains of virus, and augment a significant dose sparing activity that could improve vaccine manufacturing capacity. As an alternative to an emulsion, we tested a simple lipid-based aqueous formulation containing a synthetic TLR4 ligand (GLA-AF) for its ability to enhance protection against H5N1 infection. GLA-AF was very effective in adjuvanting recombinant H5 hemagglutinin antigen (rH5) in mice and was as potent as the stable emulsion, SE. Both adjuvants induced similar antibody titers using a sub-microgram dose of rH5, and both conferred complete protection against a highly pathogenic H5N1 challenge. However, GLA-AF was the superior adjuvant in ferrets. GLA-AF stimulated a broader antibody response than SE after both the prime and boost immunization with rH5, and ferrets were better protected against homologous and heterologous strains of H5N1 virus. Thus, GLA-AF is a potent emulsion-free adjuvant that warrants consideration for pandemic influenza vaccine development. PMID:24551202

  14. Low strain, long life creep fatigue of AF2-1DA and INCO 718

    NASA Technical Reports Server (NTRS)

    Thakker, A. B.; Cowles, B. A.

    1983-01-01

    Two aircraft turbine disk alloys, GATORIZED AF2-DA and INCO 718 were evaluated for their low strain long life creep-fatigue behavior. Static (tensile and creep rupture) and cyclic properties of both alloys were characterized. The cntrolled strain LCF tests were conducted at 760 C (1400 F) and 649 C (1200 F) for AF2-1DA and INCO 718, respectively. Hold times were varied for tensile, compressive and tensile/compressive strain dwell (relaxation) tests. Stress (creep) hold behavior of AF2-1DA was also evaluated. Generally, INCO 718 exhibited more pronounced reduction in cyclic life due to hold than AF2-1DA. The percent reduction in life for both alloys for strain dwell tests was greater at low strain ranges (longer life regime). Changing hold time from 0 to 0.5, 2.0 and 15.0 min. resulted in corresponding reductions in life. The continuous cycle and cyclic/dwell initiation failure mechanism was predominantly transgranular for AF2-1DA and intergranular for INCO 718.

  15. Effect of X irradiation on optical properties of Teflon-AF

    NASA Astrophysics Data System (ADS)

    Jahan, M. S.; Ermer, D. R.; Cooke, D. W.

    1993-03-01

    Radiation effects in optical-grade amorphous fluoropolymer, Teflon-AF, is investigated by UV-visible absorption and electron spin resonance (ESR) measurements. When irradiated with low-energy (40 kVp) X-rays at room temperature in air, Teflon-AF is found to develop a broad, structureless UV-absorption band in the wavelength interval 200-350 nm. While the UV absorption increases as a function of X-ray dose, with relative rates of approx 2 × 10 -5 Gy -1 (1 × 10 -5 Gy -1) in Teflon-AF 1600 (Teflon-AF 2400), its optical transparency for a given dose of 67.5 kGy, however, remains unaffected. Additional measurements conducted using electron spin resonance (ESR) technique reveal that the observed UV absorption is caused by the X-ray induced peroxy radical (POO .˙). The results also suggest that the inclusion of dioxole monomer in the PTFE chain not only improves the optical clarity of Teflon-AF, as reported, but also increases its radiation tolerance. During a post-irradiation storage in air at RT for about 30 days the peroxy radical is observed to decay, with a concomitant decrease in UV absorption. A tentative model is proposed to explain the radiation damage and recovery mechanisms.

  16. The response of a laminar boundary layer in supersonic flow to small amplitude progressive waves

    NASA Technical Reports Server (NTRS)

    Duck, Peter W.

    1989-01-01

    The effect of a small amplitude progressive wave on the laminar boundary layer on a semi-infinite flat plate, due to a uniform supersonic freestream flow, is considered. The perturbation to the flow divides into two streamwise zones. In the first, relatively close to the leading edge of the plate, on a transverse scale comparable to the boundary layer thickness, the perturbation flow is described by a form of the unsteady linearized compressible boundary layer equations. In the freestream, this component of flow is governed by the wave equation, the solution of which provides the outer velocity conditions for the boundary layer. This system is solved numerically, and also the asymptotic structure in the far downstream limit is studied. This reveals a breakdown and a subsequent second streamwise zone, where the flow disturbance is predominantly inviscid. The two zones are shown to match in a proper asymptotic sense.

  17. Multi-zone furnace system

    SciTech Connect

    Orbeck, G.A.

    1986-05-06

    A multi-zone furnace is described which consists of: a furnace chamber having at least one heat zone and at least one zone adjacent to the heat zone and disposed along the length of the furnace chamber; the heat zone having a hearth at a level different from the hearth level of the adjacent zone; a walking beam conveyor disposed in the furnace chamber and operative in a short stroke mode to convey a product along the hearth of the heat zone, and in a long stroke mode to convey a product from the heat zone to the adjacent zone.

  18. SOLE SOURCE AQUIFER BOUNDARY DATA

    EPA Science Inventory

    There are 7 polygons representing 6 individual sole source aquifer boundaries and one streamflow source area in California, Arizona, and Nevada. Various efforts were combined to create the final product, which represents the Federal Register boundary description. Sole source aqu...

  19. Cell boundary fault detection system

    DOEpatents

    Archer, Charles Jens; Pinnow, Kurt Walter; Ratterman, Joseph D.; Smith, Brian Edward

    2009-05-05

    A method determines a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  20. Divide et impera: boundaries shape the plant body and initiate new meristems.

    PubMed

    Wang, Quan; Hasson, Alice; Rossmann, Susanne; Theres, Klaus

    2016-01-01

    485 I. 485 II. 486 III. 491 IV. 491 V. 495 495 References 495 SUMMARY: Boundaries, established and maintained in different regions of the plant body, have diverse functions in development. One role is to separate different cell groups, for example the differentiating cells of a leaf primordium from the pluripotent cells of the apical meristem. Boundary zones are also established during compound leaf development, to separate young leaflets from each other, and in many other positions of the plant body. Recent studies have demonstrated that different boundary zones share similar properties. They are characterized by a low rate of cell divisions and specific patterns of gene expression. In addition, the levels of the plant hormones auxin and brassinosteroids are down-regulated in boundary zones, resulting in a low differentiation level of boundary cells. This feature seems to be crucial for a second important role of boundary zones, the formation of new meristems. The primary shoot meristem, as well as secondary and ectopic shoot meristems, initiate from boundary cells that exhibit competence for meristem formation. PMID:26391543

  1. Double Seismic Zones and Dehydration Embrittlement

    NASA Astrophysics Data System (ADS)

    Seno, T.; Yamasaki, T.

    2001-12-01

    Dehydration embrittlement is still an attractive mechanism for intermediate-depth earthquake occurrence. We explore the possibility whether this hypothesis can explain the observed geometry of the double seismic zones. We calculate transient temperature structures of slabs using a finite element method, based on geologically estimated subduction histories for NE Japan, SW Japan, E. Aleutian, N. Chile, Taiwan, and Cape Mendocino, where double zones have been observed. We then delineate the dehydration loci utilizing the phase diagrams of serpentine by Wunder and Schreyer (1997), Bose and Navrotsky (1998) and Ulmer and Trommsdorff (1995), and of meta-basalt by Kerrick and Connolly (2001). For slabs whose crust passes from blueschist to lawsonite-eclogite facies, we take the glaucophane-out boundary as the upper limit of the significant dehydration of meta-basalt. The dehydration loci of serpentine produces a double-layered structure for NE Japan, E. Aleutian, N. Chile, and Taiwan, whose slabs are older than 40 Ma at the trench. In these regions, the lower zone of the double zones can be explained by the lower dehydration locus of serpentine, and the upper zone by that of meta-basalt. The deepest portion of the upper zone might contain the upper dehydration locus of serpentine; however, this occurs only in NE Japan and E. Aleutian. The dehydration loci of serpentine degenerate into a single one in SW Japan and Cape Mendocino whose slabs are younger than 20 Ma at the trench. For these regions, the lower zone of the double zone is explained by the degenerated dehydration locus of serpentine and the upper zone by successive dehydration of meta-basalt from greenschist to dry eclogite facies in the shallow depth. Provided that the oceanic crust is metamorphosed into hydrated minerals at the mid-ocean ridge, the condition for the existence of a double zone is the serpentinization of the subducting oceanic plate at mid-plate depth for a cold slab and at shallow depth for a

  2. Seismic reflection imaging of two megathrust shear zones in the northern Cascadia subduction zone.

    PubMed

    Calvert, Andrew J

    2004-03-11

    At convergent continental margins, the relative motion between the subducting oceanic plate and the overriding continent is usually accommodated by movement along a single, thin interface known as a megathrust. Great thrust earthquakes occur on the shallow part of this interface where the two plates are locked together. Earthquakes of lower magnitude occur within the underlying oceanic plate, and have been linked to geochemical dehydration reactions caused by the plate's descent. Here I present deep seismic reflection data from the northern Cascadia subduction zone that show that the inter-plate boundary is up to 16 km thick and comprises two megathrust shear zones that bound a >5-km-thick, approximately 110-km-wide region of imbricated crustal rocks. Earthquakes within the subducting plate occur predominantly in two geographic bands where the dip of the plate is inferred to increase as it is forced around the edges of the imbricated inter-plate boundary zone. This implies that seismicity in the subducting slab is controlled primarily by deformation in the upper part of the plate. Slip on the shallower megathrust shear zone, which may occur by aseismic slow slip, will transport crustal rocks into the upper mantle above the subducting oceanic plate and may, in part, provide an explanation for the unusually low seismic wave speeds that are observed there. PMID:15014496

  3. Boundary terms for causal sets

    NASA Astrophysics Data System (ADS)

    Buck, Michel; Dowker, Fay; Jubb, Ian; Surya, Sumati

    2015-10-01

    We propose a family of boundary terms for the action of a causal set with a spacelike boundary. We show that in the continuum limit one recovers the Gibbons-Hawking-York boundary term in the mean. We also calculate the continuum limit of the mean causal set action for an Alexandrov interval in flat spacetime. We find that it is equal to the volume of the codimension-2 intersection of the two light-cone boundaries of the interval.

  4. Pseudomonas syringae type III effector HopAF1 suppresses plant immunity by targeting methionine recycling to block ethylene induction

    PubMed Central

    Washington, Erica J.; Mukhtar, M. Shahid; Finkel, Omri M.; Wan, Li; Kieber, Joseph J.; Dangl, Jeffery L.

    2016-01-01

    HopAF1 is a type III effector protein of unknown function encoded in the genomes of several strains of Pseudomonas syringae and other plant pathogens. Structural modeling predicted that HopAF1 is closely related to deamidase proteins. Deamidation is the irreversible substitution of an amide group with a carboxylate group. Several bacterial virulence factors are deamidases that manipulate the activity of specific host protein substrates. We identified Arabidopsis methylthioadenosine nucleosidase proteins MTN1 and MTN2 as putative targets of HopAF1 deamidation. MTNs are enzymes in the Yang cycle, which is essential for the high levels of ethylene biosynthesis in Arabidopsis. We hypothesized that HopAF1 inhibits the host defense response by manipulating MTN activity and consequently ethylene levels. We determined that bacterially delivered HopAF1 inhibits ethylene biosynthesis induced by pathogen-associated molecular patterns and that Arabidopsis mtn1 mtn2 mutant plants phenocopy the effect of HopAF1. Furthermore, we identified two conserved asparagines in MTN1 and MTN2 from Arabidopsis that confer loss of function phenotypes when deamidated via site-specific mutation. These residues are potential targets of HopAF1 deamidation. HopAF1-mediated manipulation of Yang cycle MTN proteins is likely an evolutionarily conserved mechanism whereby HopAF1 orthologs from multiple plant pathogens contribute to disease in a large variety of plant hosts. PMID:27274076

  5. A Critical Role for CRM1 in Regulating HOXA Gene Transcription in CALM-AF10 Leukemias

    PubMed Central

    Conway, Amanda E.; Haldeman, Jonathan M.; Wechsler, Daniel S.; Lavau, Catherine P.

    2014-01-01

    The leukemogenic CALM-AF10 fusion protein is found in patients with immature acute myeloid and T-lymphoid malignancies. CALM-AF10 leukemias display abnormal H3K79 methylation and increased HOXA cluster gene transcription. Elevated expression of HOXA genes is critical for leukemia maintenance and progression; however, the precise mechanism by which CALM-AF10 alters HOXA gene expression is unclear. We previously determined that CALM contains a CRM1-dependent nuclear export signal (NES), which is both necessary and sufficient for CALM-AF10-mediated leukemogenesis. Here, we find that interaction of CALM-AF10 with the nuclear export receptor CRM1 is necessary for activating HOXA gene expression. We show that CRM1 localizes to HOXA loci where it recruits CALM-AF10, leading to transcriptional and epigenetic activation of HOXA genes. Genetic and pharmacological inhibition of the CALM-CRM1 interaction prevents CALM-AF10 enrichment at HOXA chromatin, resulting in immediate loss of transcription. These results provide a comprehensive mechanism by which the CALM-AF10 translocation activates the critical HOXA cluster genes. Furthermore, this report identifies a novel function of CRM1: the ability to bind chromatin and recruit the NES-containing CALM-AF10 transcription factor. PMID:25027513

  6. An Evaluation of the Impacts of AF-M315E Propulsion Systems for Varied Mission Applications

    NASA Technical Reports Server (NTRS)

    Deans, Matthew C.; Oleson, Steven R.; Fittje, James; Colozza, Anthony; Packard, Tom; Gyekenyesi, John; McLean, Christopher H.; Spores, Ronald A.

    2015-01-01

    The purpose of the AF-M315E COMPASS study is to identify near-term (3-5 years) and long term (5 years +) opportunities for infusion, specifically the thruster and associated component technologies being developed as part of the GPIM project. Develop design reference missions which show the advantages of the AF-M315E green propulsion system. Utilize a combination of past COMPASS designs and selected new designs to demonstrate AF-M315E advantages. Use the COMPASS process to show the puts and takes of using AF-M315E at the integrated system level.

  7. AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis.

    PubMed

    Park, Jino; Schlederer, Michaela; Schreiber, Martin; Ice, Ryan; Merkel, Olaf; Bilban, Martin; Hofbauer, Sebastian; Kim, Soojin; Addison, Joseph; Zou, Jie; Ji, Chunyan; Bunting, Silvia T; Wang, Zhengqi; Shoham, Menachem; Huang, Gang; Bago-Horvath, Zsuzsanna; Gibson, Laura F; Rojanasakul, Yon; Remick, Scot; Ivanov, Alexey; Pugacheva, Elena; Bunting, Kevin D; Moriggl, Richard; Kenner, Lukas; Tse, William

    2015-08-21

    AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1. In addition, enhanced AF1q expression promotes breast cancer cell proliferation, migration, mammosphere formation, and chemo-resistance. In xenograft models, enforced AF1q expression in breast cancer cells also promotes liver metastasis and lung colonization. In a cohort of 63 breast cancer patients, higher percentages of AF1q-positive cancer cells in primary sites were associated with significantly poorer overall survival (OS), disease-free survival (DFS), and brain metastasis-free survival (b-MFS). Using paired primary/metastatic samples from the same patients, we demonstrate that AF1q-positive breast cancer cells become dynamically dominant in the metastatic sites compared to the primary sites. Our findings indicate that breast cancer cells with a hyperactive AF1q/TCF7/CD44 regulatory axis in the primary sites may represent "metastatic founder cells" which have invasive properties. PMID:26079538

  8. AF1q is a novel TCF7 co-factor which activates CD44 and promotes breast cancer metastasis

    PubMed Central

    Park, Jino; Schlederer, Michaela; Schreiber, Martin; Ice, Ryan; Merkel, Olaf; Bilban, Martin; Hofbauer, Sebastian; Kim, Soojin; Addison, Joseph; Zou, Jie; Ji, Chunyan; Bunting, Silvia T.; Wang, Zhengqi; Shoham, Menachem; Huang, Gang; Bago-Horvath, Zsuzsanna; Gibson, Laura F.; Rojanasakul, Yon; Remick, Scot; Ivanov, Alexey; Pugacheva, Elena; Bunting, Kevin D.; Moriggl, Richard

    2015-01-01

    AF1q is an MLL fusion partner that was identified from acute myeloid leukemia (AML) patients with t (1; 11) (q21; q23) chromosomal abnormality. The function of AF1q is not yet fully known, however, elevated AF1q expression is associated with poor clinical outcomes in various malignancies. Here, we show that AF1q specifically binds to T-cell-factor-7 (TCF7) in the Wnt signaling pathway and results in transcriptional activation of CD44 as well as multiple downstream targets of the TCF7/LEF1. In addition, enhanced AF1q expression promotes breast cancer cell proliferation, migration, mammosphere formation, and chemo-resistance. In xenograft models, enforced AF1q expression in breast cancer cells also promotes liver metastasis and lung colonization. In a cohort of 63 breast cancer patients, higher percentages of AF1q-positive cancer cells in primary sites were associated with significantly poorer overall survival (OS), disease-free survival (DFS), and brain metastasis-free survival (b-MFS). Using paired primary/metastatic samples from the same patients, we demonstrate that AF1q-positive breast cancer cells become dynamically dominant in the metastatic sites compared to the primary sites. Our findings indicate that breast cancer cells with a hyperactive AF1q/TCF7/CD44 regulatory axis in the primary sites may represent “metastatic founder cells” which have invasive properties. PMID:26079538

  9. Outcomes registry for better informed treatment of atrial fibrillation II: Rationale and design of the ORBIT-AF II registry

    PubMed Central

    Steinberg, Benjamin A.; Blanco, Rosalia G.; Ollis, Donna; Kim, Sunghee; Holmes, DaJuanicia N.; Kowey, Peter R.; Fonarow, Gregg C.; Ansell, Jack; Gersh, Bernard; Go, Alan S.; Hylek, Elaine; Mahaffey, Kenneth W.; Thomas, Laine; Chang, Paul; Peterson, Eric D.; Piccini, Jonathan P.

    2014-01-01

    Background Recent clinical trials have demonstrated the safety and efficacy of several non–vitamin K oral anticoagulants (NOACs) for the treatment of atrial fibrillation (AF). However, there are limited data on their use and outcomes in routine clinical practice, particularly among patients newly diagnosed as having AF and patients with AF recently transitioned to a NOAC. Methods/Design ORBIT-AF II is a multicenter, national registry of patients with AF that is enrolling up to 15,000 newly diagnosed patients with AF and/or those with AF recently transitioned to a NOAC from 300 US outpatient practices. These patients will be followed for up to 2 years, including clinical status, outcomes (major adverse cardiovascular events, bleeding), and management of anticoagulation surrounding bleeding events. In addition, detailed data regarding the use of these agents in and around cardiac procedures, their complications, and management of such complications will be collected. Conclusions The ORBIT-AF II registry will provide valuable insights into the safety and effectiveness of NOACs used in AF in community practice settings. PMID:25066554

  10. Fault zone hydrogeology

    NASA Astrophysics Data System (ADS)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (< 1 km) introduces permeability heterogeneity and anisotropy, which has an important impact on processes such as regional groundwater flow, hydrocarbon migration, and hydrothermal fluid circulation. Fault zones have the capacity to be hydraulic conduits connecting shallow and deep geological environments, but simultaneously the fault cores of many faults often form effective barriers to flow. The direct evaluation of the impact of faults to fluid flow patterns remains a challenge and requires a multidisciplinary research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and

  11. The Magnetic Signature of Zones of Continental Collision

    NASA Astrophysics Data System (ADS)

    Purucker, M. E.; Whaler, K. A.

    2007-12-01

    Near-surface and satellite maps of the crustal component of the magnetic field can be interpreted in terms of thermal conditions at depth because the magnetic properties of rocks depend on their temperature. Observations related to continental deformation at diffuse plate boundaries are often considered in relation to three length scales: the thickness of the seismogenic upper crust, the entire continental crust, and the mechanical lithosphere. The lower boundary of the magnetic crust coincides with the Moho, or in the presence of an elevated geotherm, with the Curie isotherm. New global perspectives on the magnetic signature of zones of continental collision are afforded by the recently published Magnetic Anomaly Map of the World (Purucker, 2007, EOS, 88, 263), the MF-5 satellite magnetic field (Maus et al., 2007, Gcubed), and NASA's ST-5 constellation mission in 2006. The thickness of the magnetic crust can be estimated by integrating the MF-5 satellite magnetic field into the 3SMAC compositional and thermal model of the lithosphere, and a minimum estimate of the magnetization can be estimated using a Greens function approach. We compare our magnetic maps with the diffuse plate boundary maps of Gordon (1998) and Dumoulin et al. (1998). The diffuse plate boundary zones exhibit intermediate (22-31 km) magnetic thicknessses, significantly less than those of the adjacent stable plate. The diffuse NE Asia plate boundary zone, from the Lena River delta to the Sea of Okhotsk, is especially well- expressed in both satellite and near-surface magnetic maps.

  12. Redefinition of the Meramecian/Chesterian boundary (Mississippian)

    SciTech Connect

    Maples, C.G.; Waters, J.A.

    1987-07-01

    The Meramecian/Chesterian (Mississippi) boundary in the type area is currently defined as the highest occurrence of the crinoid Platycrinites penicillus and the lowest occurrence of the crinoid genera Agassizocrinus and Talarocrinus. Because these taxa have not been reported outside eastern North America, attempts have been made to use conodonts and Foraminifera to extend the Meramecian/Chesterian boundary outside the type area. Unfortunately, changes in conodont and foraminiferal assemblages do not coincide with the currently defined Meramecian/Chesterian boundary, and use of these fossil groups does not allow exact placement of the boundary outside of eastern North America. The authors suggest that the Meramecian/Chesterian boundary be redefined as the boundary between Foraminiferal Zones 15 and 16i of the Mamet scheme, irrespective of the occurrence of Platycrinites penicillus. This change in definition places the Ste. Genevieve Limestone (Genevievian Stage) in the lowermost part of the Chesterian Series, with which it is biotically and sedimentologically more allied than with the underlying St. Louis Limestone. This change provides a sound biostratigraphic base for correlating the Meramecian/Chesterian boundary outside of the type area. Foraminifera, conodonts, brachiopods, and corals all show significant changes at or slightly below the St. Louis/Ste. Genevieve contact rather than at the Genevievian/Chesterian contact. 52 references.

  13. Magnetostratigraphy of a Marine Triassic-Jurassic Boundary Section, Kennecott Point, Queen Charlotte Islands: Implications for the Temporal Correlation of a 'Big Five' Mass Extinction Event.

    NASA Astrophysics Data System (ADS)

    Hilburn, I. A.; Kirschvink, J. L.; Ward, P. D.; Haggart, J. W.; Raub, T. D.

    2008-12-01

    Several causes have been proposed for Triassic-Jurassic (T-J) boundary extinctions, including global ocean anoxia/euxinia, an impact event, and/or eruption of the massive Central Atlantic Magmatic Province (CAMP), but poor intercontinental correlation makes testing these difficult. Sections at Kennecott Point, Queen Charlotte Islands, British Columbia span the late Norian through Rhaetian (Triassic) and into the earliest Hettangian (Jurassic) and provide the best integrated magneto- and chemostratigraphic framework for placing necessary temporal constraints upon the T-J mass extinctions. At Kennecott Point, turnover of radiolaria and ammonoids define the T-J boundary marine extinction and are coincident with a 2 ‰ negative excursion in δ13Corg similar in magnitude to that observed at Ferguson Hill (Muller Canyon), Nevada (1, 2). With Conodont Alteration Index values in the 1-2 range, Kennecott Point provides the ideal setting for use of magnetostratigraphy to tie the marine isotope excursion into the chronostratigraphic framework of the Newark, Hartford, and Fundy Basins. In the summer of 2005, we collected a ~1m resolution magnetostratigraphic section from 105 m of deep marine, silt- and sandstone turbidites and interbedded mudstones, spanning the T-J boundary at Kennecott Point. Hybrid progressive demagnetization - including zero-field, low-temperature cycling; low-field AF cleaning; and thermal demagnetization in ~25°C steps to 445°C under flowing N2 gas (3) - first removed a Northerly, steeply inclined component interpreted to be a Tertiary overprint, revealing an underlying dual-polarity component of moderate inclination. Five major polarity zones extend through our section, with several short, one-sample reversals interspersed amongst them. Comparison of this pattern with other T-J boundary sections (4-6) argues for a Northern hemisphere origin of our site, albeit with large vertical-axis rotations. A long normal chron bounds the T-J boundary punctuated

  14. Design and position control of AF lens actuator for mobile phone using IPMC-EMIM

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Joo; Kim, Chul-Jin; Park, No-Cheol; Yang, Hyun-Seok; Park, Young-Pil; Park, Kang-Ho; Lee, Hyung-Kun; Choi, Nak-Jin

    2008-03-01

    IPMC-EMIM (Ionic Polyer Metal Composites + 1-ethyl-3- methyl imidazolium trifluromethane sulfonate, EMIM-Tfo) is fabricated by substituting ionic liquid for water in Nafion film, which improves water sensitiveness of IPMC and guarantees uniform performance regardless of the surrounding environment. In this paper, we will briefly introduce the procedure of fabrication of IPMC-EMIM and proceed to introduce the Hook-type actuator using IPMC-EMIM and application to AF Lens actuator. Parameters of Hook-type actuator are estimated from experimental data. In the simulation, The proposed AF Lens Actuator is assumed to be a linear system and based on estimated parameters, PID controller will be designed and controlled motion of AF Lens actuator will be shown through simulation.

  15. Effects of Oxides on Tensile and Charpy Impact Properties and Fracture Toughness in Heat Affected Zones of Oxide-Containing API X80 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Sung, Hyo Kyung; Sohn, Seok Su; Shin, Sang Yong; Oh, Kyung Shik; Lee, Sunghak

    2014-06-01

    This study is concerned with effects of complex oxides on acicular ferrite (AF) formation, tensile and Charpy impact properties, and fracture toughness in heat affected zones (HAZs) of oxide-containing API X80 linepipe steels. Three steels were fabricated by adding Mg and O2 to form oxides, and various HAZ microstructures were obtained by conducting HAZ simulation tests under different heat inputs. The no. of oxides increased with increasing amount of Mg and O2, while the volume fraction of AF present in the steel HAZs increased with increasing the no. of oxides. The strengths of the HAZ specimens were generally higher than those of the base metals because of the formation of hard microstructures of bainitic ferrite and granular bainite. When the total Charpy absorbed energy was divided into the fracture initiation and propagation energies, the fracture initiation energy was maintained constant at about 75 J at room temperature, irrespective of volume fraction of AF. The fracture propagation energy rapidly increased from 75 to 150 J and saturated when the volume fraction of AF exceeded 30 pct. At 253 K (-20 °C), the total absorbed energy increased with increasing volume fraction of AF, as the cleavage fracture was changed to the ductile fracture when the volume fraction of AF exceeded 45 pct. Thus, 45 vol pct of AF at least was needed to improve the Charpy impact energy, which could be achieved by forming a no. of oxides. The fracture toughness increased with increasing the no. of oxides because of the increased volume fraction of AF formed around oxides. The fracture toughness did not show a visible correlation with the Charpy absorbed energy at room temperature, because toughness properties obtained from these two toughness testing methods had different significations in view of fracture mechanics.

  16. Cloning and characterization of two duplicated interleukin-17A/F2 genes in common carp (Cyprinus carpio L.): Transcripts expression and bioactivity of recombinant IL-17A/F2.

    PubMed

    Li, Hongxia; Yu, Juhua; Li, Jianlin; Tang, Yongkai; Yu, Fan; Zhou, Jie; Yu, Wenjuan

    2016-04-01

    Interleukin-17 (IL-17) plays an important role in inflammation and host defense in mammals. In this study, we identified two duplicated IL-17A/F2 genes in the common carp (Cyprinus carpio) (ccIL-17A/F2a and ccIL-17A/F2b), putative encoded proteins contain 140 amino acids (aa) with conserved IL-17 family motifs. Expression analysis revealed high constitutive expression of ccIL-17A/F2s in mucosal tissues, including gill, skin and intestine, their expression could be induced by Aeromonas hydrophila, suggesting a potential role in mucosal immunity. Recombinant ccIL-17A/F2a protein (rccIL-17A/F2a) produced in Escherichia coli could induce the expression of proinflammatory cytokines (IL-1β) and the antimicrobial peptides S100A1, S100A10a and S100A10b in the primary kidney in a dose- and time-dependent manner. Above findings suggest that ccIL-17A/F2 plays an important role in both proinflammatory and innate immunity. Two duplicated ccIL-17A/F2s showed different expression level with ccIL-17A/F2a higher than b, comparison of two 5' regulatory regions indicated the length from anticipated promoter to transcriptional start site (TSS) and putative transcription factor binding site (TFBS) were different. Promoter activity of ccIL-17A/F2a was 2.5 times of ccIL-17A/F2b which consistent with expression results of two genes. These suggest mutations in 5'regulatory region contributed to the differentiation of duplicated genes. To our knowledge, this is the first report to analyze 5'regulatory region of piscine IL-17 family genes. PMID:26921542

  17. Boundaries and Boundary Marks - Substantive Cultural Heritage of Extensive Importance

    NASA Astrophysics Data System (ADS)

    Waldhaeusl, P.; Koenig, H.; Mansberger, R.

    2015-08-01

    The Austrian Society for surveying and Geoinformation (ASG) has proposed to submit "Boundaries and Boundary Marks" for the UNESCO World Heritage title. It was time that boundaries, borders and limits of all types as well as ownership rights would find the proper attention in the global public. Landmarks symbolize the real property and the associated rights and obligations, in a figurative sense, the property generally and all legal limits. A democratic state of law is impossible at today's population density without a functioning land administration system with surveying and jurisdiction. As monumental World Heritage representatives of the geodetic artwork "Boundaries and Boundary Marks" are specifically proposed: remaining monuments of the original cadastral geodetic network, the first pan-Austrian surveying headquarters in Vienna, and a specific selection of outstanding boundary monuments. Landmarks are monuments to the boundaries which separate rights and obligations, but also connect the neighbors peacefully after written agreement. "And cursed be he who does not respect the boundaries" you wrote already 3000 years ago. Boundaries and Boundary Marks are a real thing; they all belong to the tangible or material heritage of human history. In this context also the intangible heritage is discussed. This refers to oral tradition and expressions, performing arts; social practices, rituals and festive events; as well as to knowledge and practices handling nature and the universe. "Boundaries and Boundary Marks" do not belong to it, but clearly to the material cultural world heritage. "Boundary and Boundary Marks" is proposed to be listed according to the criteria (ii),(iv),(vi).

  18. Open boundary molecular dynamics

    NASA Astrophysics Data System (ADS)

    Delgado-Buscalioni, R.; Sablić, J.; Praprotnik, M.

    2015-09-01

    This contribution analyzes several strategies and combination of methodologies to perform molecular dynamic simulations in open systems. Here, the term open indicates that the total system has boundaries where transfer of mass, momentum and energy can take place. This formalism, which we call Open Boundary Molecular Dynamics (OBMD), can act as interface of different schemes, such as Adaptive Resolution Scheme (AdResS) and Hybrid continuum-particle dynamics to link atomistic, coarse-grained (CG) and continuum (Eulerian) fluid dynamics in the general framework of fluctuating Navier-Stokes equations. The core domain of the simulation box is solved using all-atom descriptions. The CG layer introduced using AdResS is located at the outer part of the open box to make feasible the insertion of large molecules into the system. Communications between the molecular system and the outer world are carried out in the outer layers, called buffers. These coupling preserve momentum and mass conservation laws and can thus be linked with Eulerian hydro- dynamic solvers. In its simpler form, OBMD allows, however, to impose a local pressure tensor and a heat flux across the system's boundaries. For a one component molecular system, the external normal pressure and temperature determine the external chemical potential and thus the independent parameters of a grand-canonical ensemble simulation. Extended ensembles under non-equilibrium stationary states can also be simulated as well as time dependent forcings (e.g. oscillatory rheology). To illustrate the robustness of the combined OBMD-AdResS method, we present simulations of star-polymer melts at equilibrium and in sheared flow.

  19. BOUndary Plasma Turbulence

    2008-01-25

    BOUT is a parallelized 3D nonlocal electromagnetic turbulence code. The principal calculations are the boundary plasma turbulence in a realistic magnetic geometry. BOUT uses fluid Braginskii equations for plasma vorticity, density, electron and ion temperature and Parallel mementum. With sources added in the core-edge region and sinks in the scrape-off-layer (SOL), BOUT follows the self-consistent profile evolution together with turbulence. BOUT also includes coupling to a magnetohyfrodynamic equlibrium (EFIT package) and a two-dimensional hydrodynamic edgemore » transport model (UEDGE package).« less

  20. Compliance testing of the Clear AFS Power Plant, coal-fired boiler 1, Clear AFS, Alaska. Final report, 18-23 April 1989

    SciTech Connect

    Scott, P.T.

    1989-10-01

    The 13 MWS/DE through HQ AFSPACECOM/SG requested AFOEHL Quality Function conduct source emission testing of the Clear AFS Power Plant to determine compliance with applicable Alaska Air Quality Control Codes. The Alaska Department of Environmental Conservation required testing of one representative boiler for permit compliance and to determine operating limitations for each boiler. At 80,000 lbs steam/hour particulate emission were within emission limits allowed by the State of Alaska.

  1. Microgravity silicon zoning investigation

    NASA Technical Reports Server (NTRS)

    Kern, E. L.; Gill, G. L., Jr.

    1985-01-01

    The flow instabilities in floating zones of silicon were investigated and methods for investigation of these instabilities in microgravity were defined. Three principal tasks were involved: (1) characterization of the float zone in small diameter rods; (2) investigation of melt flow instabilities in circular melts in silicon disks; and (3) the development of a prototype of an apparatus that could be used in near term space experiments to investigate flow instabilities in a molten zone. It is shown that in a resistance heated zoner with 4 to 7 mm diameter silicon rods that the critical Marangoni number is about 1480 compared to a predicted value of 14 indicative that viable space experiments might be performed. The prototype float zone apparatus is built and specifications are prepared for a flight zoner should a decision be reached to proceed with a space flight experimental investigation.

  2. Theory of zone radiometry

    NASA Technical Reports Server (NTRS)

    Farmer, R. C.; Audeh, B. J.

    1973-01-01

    A spectroscopic instrumentation system was developed which was used to measure temperature and concentration distributions in axisymmetric and two dimensional combusting flows. This measurement technique is known as zone radiometry.

  3. A sharp and flat section of the core-mantle boundary

    USGS Publications Warehouse

    Vidale, J.E.; Benz, H.M.

    1992-01-01

    THE transition zone between the Earth's core and mantle plays an important role as a boundary layer for mantle and core convection1. This zone conducts a large amount of heat from the core to the mantle, and contains at least one thermal boundary layer2,3; the proximity of reactive silicates and molten iron leads to the possibility of zones of intermediate composition4. Here we investigate one region of the core-mantle boundary using seismic waves that are converted from shear to compressional waves by reflection at the boundary. The use of this phase (known as ScP), the large number of receiving stations, and the large aperture of our array all provide higher resolution than has previously been possible5-7. For the 350-km-long section of the core-mantle boundary under the northeast Pacific sampled by the reflections, the local boundary topography has an amplitude of less than 500 m, no sharp radial gradients exist in the 400 km above the boundary, and the mantle-lo-core transition occurs over less than 1 km. The simplicity of the structure near and above the core-mantle boundary argues against chemical heterogeneity at the base of the mantle in this location.

  4. 33 CFR 3.70-20 - Activities Far East Marine Inspection Zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Activities Far East Marine... ZONES Fourteenth Coast Guard District § 3.70-20 Activities Far East Marine Inspection Zone. (a) Activities Far East's office is located in Yokota, Japan. The boundaries of Activities Far East's...

  5. 44 CFR 64.5 - Relationship of rates to zone designations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the entire community at chargeable rates (i.e., subsidized) for first layer coverage of existing... authorize the sale of such insurance without designating any Zones A, M, or E within a community, provided... technical information to delineate Zones A, M, or E, he/she shall delineate the tentative boundaries on...

  6. 75 FR 12731 - Foreign-Trade Zone 50-Long Beach, CA; Site Renumbering Notice

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-17

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Foreign-Trade Zone 50--Long Beach, CA; Site Renumbering Notice Foreign-Trade... the Long Beach/Los Angeles area. The current update does not alter the physical boundaries that...

  7. 33 CFR 165.106 - Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone: Seabrook Nuclear... Guard District § 165.106 Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire. (a... property boundary of Seabrook Nuclear Power Plant identified as follows: beginning at position 42°53′58″...

  8. 33 CFR 165.106 - Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone: Seabrook Nuclear... Guard District § 165.106 Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire. (a... property boundary of Seabrook Nuclear Power Plant identified as follows: beginning at position 42°53′58″...

  9. 33 CFR 165.106 - Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone: Seabrook Nuclear... Guard District § 165.106 Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire. (a... property boundary of Seabrook Nuclear Power Plant identified as follows: beginning at position 42°53′58″...

  10. 33 CFR 165.106 - Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone: Seabrook Nuclear... Guard District § 165.106 Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire. (a... property boundary of Seabrook Nuclear Power Plant identified as follows: beginning at position 42°53′58″...

  11. 33 CFR 165.106 - Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone: Seabrook Nuclear... Guard District § 165.106 Security Zone: Seabrook Nuclear Power Plant, Seabrook, New Hampshire. (a... property boundary of Seabrook Nuclear Power Plant identified as follows: beginning at position 42°53′58″...

  12. 33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... below the surface of the water within the boundaries of this security zone. ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Security Zone: Walkers Point... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS...

  13. 33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... below the surface of the water within the boundaries of this security zone. ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Security Zone: Walkers Point... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS...

  14. 33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... below the surface of the water within the boundaries of this security zone. ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone: Walkers Point... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS...

  15. 33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... below the surface of the water within the boundaries of this security zone. ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Security Zone: Walkers Point... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS...

  16. 33 CFR 165.102 - Security Zone: Walkers Point, Kennebunkport ME.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... below the surface of the water within the boundaries of this security zone. ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Security Zone: Walkers Point... SECURITY (CONTINUED) PORTS AND WATERWAYS SAFETY REGULATED NAVIGATION AREAS AND LIMITED ACCESS...

  17. Boundary anomalies and correlation functions

    NASA Astrophysics Data System (ADS)

    Huang, Kuo-Wei

    2016-08-01

    It was shown recently that boundary terms of conformal anomalies recover the universal contribution to the entanglement entropy and also play an important role in the boundary monotonicity theorem of odd-dimensional quantum field theories. Motivated by these results, we investigate relationships between boundary anomalies and the stress tensor correlation functions in conformal field theories. In particular, we focus on how the conformal Ward identity and the renormalization group equation are modified by boundary central charges. Renormalized stress tensors induced by boundary Weyl invariants are also discussed, with examples in spherical and cylindrical geometries.

  18. The Hale solar sector boundary

    NASA Technical Reports Server (NTRS)

    Svalgaard, L.; Wilcox, J. M.

    1976-01-01

    A Hale solar-sector boundary is defined as that half (northern hemisphere or southern hemisphere) of a sector boundary in which the change of sector-magnetic-field polarity is the same as the change of polarity from a preceding spot to a following spot. Above a Hale sector boundary the green corona has maximum brightness, while above a non-Hale boundary the green corona has a minimum brightness. The Hale portion of a photospheric sector boundary tends to have maximum magnetic-field strength, while the non-Hale portion has minimum field strength.

  19. The Hale solar sector boundary

    NASA Technical Reports Server (NTRS)

    Svalgaard, L.; Wilcox, J. M.

    1976-01-01

    A Hale solar sector boundary is defined as the half (Northern Hemisphere or Southern Hemisphere) of a sector boundary in which the change of sector magnetic field polarity is the same as the change of polarity from a preceding spot to a following spot. Above a Hale sector boundary the green corona has maximum brightness, while above a non-Hale boundary the green corona has a minimum brightness. The Hale portion of a photospheric sector boundary tends to have maximum magnetic field strength, while the non-Hale portion has minimum field strength.

  20. A classification of ecological boundaries

    USGS Publications Warehouse

    Strayer, D.L.; Power, M.E.; Fagan, W.F.; Pickett, S.T.A.; Belnap, J.

    2003-01-01

    Ecologists use the term boundary to refer to a wide range of real and conceptual structures. Because imprecise terminology may impede the search for general patterns and theories about ecological boundaries, we present a classification of the attributes of ecological boundaries to aid in communication and theory development. Ecological boundaries may differ in their origin and maintenance, their spatial structure, their function, and their temporal dynamics. A classification system based on these attributes should help ecologists determine whether boundaries are truly comparable. This system can be applied when comparing empirical studies, comparing theories, and testing theoretical predictions against empirical results.

  1. Hydrothermal experiments on serpentinization at crust/mantle boundary

    NASA Astrophysics Data System (ADS)

    Oyanagi, R.; Okamoto, A.; Tsuchiya, N.

    2013-12-01

    Serpentinization commonly proceeds in seafloor hydrothermal systems at mid-ocean ridges, along the bending faults, and at the boundary of wedge mantle and subducting plate. Silica activity are key factors in controlling reaction paths and the rate of serpentinization (e.g., Frost and Beard, 2007; Klein et al., 2009; Ogasawara et al.,2013). However, most of the previous experimental studies focused on bulk solid materials and solutions within the reaction vessel, and local changes of products reaction rate in response to concentration gradient have not been clarified. Ogasawara et al. (2013) conducted hydrothermal experiments in Ol-Opx-H2O system, and modeled the progress of serpentinization by coupled reactions and silica diffusion. In their experiment, reaction product is only serpentine and no talc or brucite were found. In this study, we conducted hydrothermal experiments in olivine (Ol)-quartz (Qtz)-H2O and Ol-plagioclase (Pl)-H2O systems as the analogue of crust/mantle boundary. The condition was 250 degreeC and at a vapor-saturated pressure. Composite powders (composed of Qtz/Ol zone, or Pl/Ol zone) were set in tube-in-tube vessels, and then loaded into autocrave with fluid ( NaOHaq, pH = 13.8 at 25 degreeC ). Runnig time is up to 25 days and maximum water content in the products is 12 wt% H2O. After the experiments, solution chemistry and the extent of serpentinization were analyzed in detail. In the Ol-Qtz-H2O experiments, we observed systematic changes of reaction products in the Ol zone. Smectite and serpentine was formed at Ol-Qtz boundary due to high Na concentration although talc is expected to form in MgO-SiO2-H2O system at Ol-Qtz boundary. Mg/Si ratio of products from EDS analyze shows high Si gradient near the boundary indicate that amount of smectite decreased with increasing distance from the Ol-Qtz boundary and only serpentine zone was observed at ~10mm. At >10mm away from Ol-Qtz boundary, serpentine ( chrysotile nano tubes) and brucite was

  2. Seismotectonics of the southern boundary of Anatolia, eastern Mediterranean region: Subduction, collision, and arc jumping

    NASA Astrophysics Data System (ADS)

    Rotstein, Yair; Kafka, Alan L.

    1982-09-01

    The pattern of seismicity and fault plane solutions of earthquakes are used to outline the tectonic features of the southern boundary of Anatolia in the eastern Mediterranean and southeastern Turkey. The results of this study show that this boundary is composed of two distinct parts. One, in southeastern Turkey and Syria, is a wide and complex zone of continental collision. The other, in the Levantine basin of the eastern Mediterranean, is a zone of oceanic subduction. In the region of continental collision three zones of seismicity are observed. Most of the seismic activity in this region follows the Bitlis zone and is associated with a zone of thrusting and mountain building. This appears to be the zone of most active deformation and plate consumption in the plate boundary region between Arabia and Turkey. A less active zone of seismicity to the north of the Bitlis zone is interpreted to have been more active in the past whereas another active zone of seismicity to the south is interpreted to be a zone which may be more active in the future as the main zone of plate consumption jumps to the south. In the subduction zone of the eastern Mediterranean the depth of the subducted slab and the rate of seismicity generally increase from east to west. The zone of present-day convergence between Africa and Turkey in the Levantine basin can be best outlined by the northern edge of the Mediterranean ridge. The subduction zone in this area sequentially jumps to the south as small continental fragments collide with existing zones of subduction. Deep seismic activity near the Gulf of Antalya is associated with a detached subducted slab north of the Anaximander Mountains that is distinctly different from the seismic trend which is associated with present-day active subduction. The plate boundary between Africa and Turkey at the center of the Levantine basin appears to have shifted to the south of the Anaximander Mountains and Florence rise. Most of the focal mechanisms of the

  3. Kinematics of the Eastern California shear zone: Evidence for slip transfer from Owens and Saline Valley fault zones to Fish Lake Valley fault zone

    USGS Publications Warehouse

    Reheis, M.C.; Dixon, T.H.

    1996-01-01

    Late Quaternary slip rates and satellite-based geodetic data for the western Great Basin constrain regional fault-slip distribution and evolution. The geologic slip rate on the Fish Lake Valley fault zone (the northwest extension of the Furnace Creek fault zone) increases northward from about 3 to 5 mm/yr, in agreement with modeled geodetic data. The increase coincides with the intersections of the Deep Springs fault, connected to the Owens Valley fault zone, and of other faults connected to the Saline Valley fault. The combined geologic and geodetic data suggest that (1) the northwest-striking faults of the Eastern California shear zone north of the Garlock fault are connected by north- to northeast-striking normal faults that transfer slip in a series of right steps, and (2) the amount and distribution of slip among the many faults of this broad, complex plate boundary have changed through time.

  4. 27. "SITE PLAN." Specifications No. OC15775, Drawing No. AF600915, sheet ...

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

    27. "SITE PLAN." Specifications No. OC1-57-75, Drawing No. AF-60-09-15, sheet 1 of 96, D.O. Series No. AF 1394/20, Rev. B. Stamped: RECORD DRAWING - AS CONSTRUCTED. Below stamp: Contract no. 5296 Rev. B, Date: 11/17/59. Site plan of 20,000-foot track, including construction phasing notes. - Edwards Air Force Base, South Base Sled Track, Edwards Air Force Base, North of Avenue B, between 100th & 140th Streets East, Lancaster, Los Angeles County, CA

  5. Multi-object spectroscopy data reduction: the AF2+WYFFOS pipeline

    NASA Astrophysics Data System (ADS)

    Domínquez Palmero, Lilian; Jackson, Richard; Molaeinezhad, Alireza; Fariña, Cecilia; Balcells, Marc; Benn, Chris R.

    2014-08-01

    The scientific productivity of complex instrumentation strongly depends on the availability of data-reduction pipelines. In the case of AF2+WYFFOS, the multi-object one-degree field-of-view fibre-fed spectrograph at the 4.2 m William Herschel Telescope (WHT), the full scientific exploitation of the data has often been slowed down because of the non-availability of a pipeline. A dedicated pipeline has been developed to overcome this. Running in IDL, it performs full reduction of AF2+WYFFOS data: fibre-to-fibre sensitivity corrections, fibre tracing, wavelength calibration, optimal extraction, sky subtraction.

  6. Modeling spall in HY100, HY130, and AF1410 steels

    NASA Astrophysics Data System (ADS)

    Garrett, R. K.; Rajendran, A. M.; Last, H. R.

    1996-05-01

    A comparison spall analysis between three matensitic steels: HY100, HY130, and AF1410 is presented Metallurgical observations on the fracture surfaces of uniaxial tensile specimens as well as the spalled target plates confirmed the nucleation, growth, and coalescence of microvoids in these steels. The threshold stress for void nucleation in these steels were determined from the spall analysis using the EPIC finite element code. According to the model, the spall nucleation occurred at higher stress levels in AF1410 compared to HY100 and HY130. A complete set of material model constants has been determined for these three steels.

  7. Saltwater upconing zone of influence

    NASA Astrophysics Data System (ADS)

    Jakovovic, Danica; Werner, Adrian D.; de Louw, Perry G. B.; Post, Vincent E. A.; Morgan, Leanne K.

    2016-08-01

    In this study, we define and characterize the saltwater upconing zone of influence (SUZI). The SUZI is the region around a pumping well within which significant rise in the saltwater-freshwater interface occurs. While the zone of influence of a pumping well can be clearly defined in terms of hydraulics (e.g., drawdown), the SUZI has not been recognised and characterised, despite its importance for groundwater decision-making in coastal regions. We explore the SUZI under various conditions and compare common methods of investigation using both axisymmetric (1D and 2D vertical cross-section) and 3D simulations of saltwater upconing at the field scale, based on a combination of numerical and analytical approaches. The SUZI was found to be dependent on the relative magnitudes of pumping, regional flow, distance of the well from the coast, and position of the well above the interface, as expected. The three-dimensional coastal setting simulations revealed an asymmetric shape of the lateral extent of the SUZI, which is largest in the direction parallel to the coast. This occurs because the ocean and the inland extent of the seawater wedge limit the propagation of the SUZI perpendicular to the coast. Predictions of the SUZI using the Ghyben-Herzberg approximation, including cases where sloping interfaces occur (i.e., in contrast to the artificiality of horizontal interfaces used in axisymmetric approaches), provide reasonable first approximations of the SUZI. Numerical modelling of dispersive upconing in the 3D inclined interface case is influenced by practical limits to the model domain size and grid resolution. For example, the no-flow boundary condition at 1500 m from the pumping well elongates the SUZI in the direction parallel to the coast. This study extends previous concepts of well interference, which have previously been based on hydraulics only, by introducing the SUZI and characterising its extent, with consideration given to differences in commonly adopted

  8. A CALM-derived nuclear export signal is essential for CALM-AF10–mediated leukemogenesis

    PubMed Central

    Conway, Amanda E.; Scotland, Paula B.; Lavau, Catherine P.

    2013-01-01

    The t(10;11) chromosomal translocation gives rise to the CALM-AF10 fusion gene and is found in patients with aggressive and difficult-to-treat hematopoietic malignancies. CALM-AF10–driven leukemias are characterized by HOXA gene up-regulation and a global reduction in H3K79 methylation. DOT1L, the H3K79 methyltransferase, interacts with the octapeptide/leucine zipper domain of AF10, and this region has been shown to be necessary and sufficient for CALM-AF10–mediated transformation. However, the precise role of CALM in leukemogenesis remains unclear. Here, we show that CALM contains a nuclear export signal (NES) that mediates cytoplasmic localization of CALM-AF10 and is necessary for CALM-AF10–dependent transformation. Fusions of the CALM NES (NESCALM-AF10) or NES motifs from heterologous proteins (ABL1, Rev, PKIA, APC) in-frame with AF10 are sufficient to immortalize murine hematopoietic progenitors in vitro. The CALM NES is essential for CALM-AF10–dependent Hoxa gene up-regulation and aberrant H3K79 methylation, possibly by mislocalization of DOT1L. Finally, we observed that CALM-AF10 leukemia cells are selectively sensitive to inhibition of nuclear export by Leptomycin B. These findings uncover a novel mechanism of leukemogenesis mediated by the nuclear export pathway and support further investigation of the utility of nuclear export inhibitors as therapeutic agents for patients with CALM-AF10 leukemias. PMID:23487024

  9. The splicing factor U2AF65 stabilizes TRF1 protein by inhibiting its ubiquitin-dependent proteolysis

    SciTech Connect

    Kim, Jeonghee; Chung, In Kwon

    2014-01-17

    Highlights: •Identification of U2AF65 as a novel TRF1-interacting protein. •U2AF65 stabilizes TRF1 protein by inhibiting its ubiquitin-dependent proteolysis. •U2AF65 interferes with the interaction between TRF1 and Fbx4. •U2AF65 represents a new route for modulating TRF1 function at telomeres. -- Abstract: The human telomeric protein TRF1 is a component of the six-subunit protein complex shelterin, which provides telomere protection by organizing the telomere into a high-order structure. TRF1 functions as a negative regulator of telomere length by controlling the access of telomerase to telomeres. Thus, the cellular abundance of TRF1 at telomeres should be maintained and tightly regulated to ensure proper telomere function. Here, we identify U2 small nuclear ribonucleoprotein (snRNP) auxiliary factor 65 (U2AF65), an essential pre-mRNA splicing factor, as a novel TRF1-interacting protein. U2AF65 interacts with TRF1 in vitro and in vivo and is capable of stabilizing TRF1 protein by inhibiting its ubiquitin-dependent proteolysis. We also found that U2AF65 interferes with the interaction between TRF1 and Fbx4, an E3 ubiquitin ligase for TRF1. Depletion of endogenous U2AF65 expression by short interfering RNA (siRNA) reduced the stability of endogenous TRF1 whereas overexpression of U2AF65 significantly extended the half-life of TRF1. These findings demonstrate that U2AF65 plays a critical role in regulating the level of TRF1 through physical interaction and ubiquitin-mediated proteolysis. Hence, U2AF65 represents a new route for modulating TRF1 function at telomeres.

  10. Diamond Formation in association with Deep Mantle Dehydration Zones

    NASA Astrophysics Data System (ADS)

    Harte, B.

    2009-12-01

    INTRODUCTION. During the last 25 years a series of publications have documented the occurrence of inclusions in diamonds that show mineral compositions and mineral associations predicted for mantle rocks at deeper levels than the mantle lithosphere (e.g Harte et al., 1999; Harte & Cayzer, 2007). Although the diamonds bearing deep mantle inclusions are not abundant in absolute terms they are widespread and have been reported from cratonic blocks on all major continents. DEPTH ZONES OF INCLUSION SUITES. The silicate inclusions and their mineral associations form a series showing good correlation with mineral assemblages expected in basic and ultrabasic rock compositions at depth. However, there is a strong bias towards assemblages from two principal zones: (1)uppermost Transition zone and Asthenosphere. (2)lowermost Transition Zone and uppermost Lower Mantle. In the case of (1) the assemblages are predominantly of majorite garnet, and majorite garnet + cpx with an affinity to eclogitic bulk compositions. In many of these inclusions the cpx appears to have exsolved from the majoritic garnet and the depth of origin of the initial inclusions may be near the top of the Transition Zone. The assemblages from (2) are predominantly of peridotic affinity and involve fPer as well as silicates. They indicate material from three depth zones near the upper mantle to lower mantle boundary (UM/LM boundary). 2a) Upper/Lower Mantle Boundary association - inclusions of: Mg2SiO4, fPer, majorite/TAPP, MgSi-perovskite(mpv), CaSi-perovskite (cpv). 2b) uppermost Lower Mantle association with: Mpv(Al-poor), fPer and cpv, majorite/tapp 2c)lower Mantle association with: Mpv(Al-rich) with fPer, and corundum. DISCUSSION. The above features show that the formation of deep mantle diamonds is concentrated in a zone around the top of the Transition Zone (ca 400-500 kms deep), and a zone at 600-800 kms embracing the bottom of the Transition Zone and the top of Lower Mantle. Associations including Mg

  11. 33 CFR 165.130 - Sandy Hook Bay, New Jersey-security zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-security zone. 165.130 Section 165.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Hook Bay, New Jersey—security zone. (a) Naval Ammunition Depot Piers. The navigable waters within the following boundaries are a security zone: A line beginning on the shore at 40°25′55.6″ N, 074°04′31.4″...

  12. 33 CFR 165.130 - Sandy Hook Bay, New Jersey-security zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-security zone. 165.130 Section 165.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Hook Bay, New Jersey—security zone. (a) Naval Ammunition Depot Piers. The navigable waters within the following boundaries are a security zone: A line beginning on the shore at 40°25′55.6″ N, 074°04′31.4″...

  13. 33 CFR 165.130 - Sandy Hook Bay, New Jersey-security zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-security zone. 165.130 Section 165.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Hook Bay, New Jersey—security zone. (a) Naval Ammunition Depot Piers. The navigable waters within the following boundaries are a security zone: A line beginning on the shore at 40°25′55.6″ N, 074°04′31.4″...

  14. 33 CFR 165.130 - Sandy Hook Bay, New Jersey-security zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-security zone. 165.130 Section 165.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Hook Bay, New Jersey—security zone. (a) Naval Ammunition Depot Piers. The navigable waters within the following boundaries are a security zone: A line beginning on the shore at 40°25′55.6″ N, 074°04′31.4″...

  15. 33 CFR 165.130 - Sandy Hook Bay, New Jersey-security zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-security zone. 165.130 Section 165.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Hook Bay, New Jersey—security zone. (a) Naval Ammunition Depot Piers. The navigable waters within the following boundaries are a security zone: A line beginning on the shore at 40°25′55.6″ N, 074°04′31.4″...

  16. The Arabia-India plate boundary unveiled

    NASA Astrophysics Data System (ADS)

    Fournier, M.; Chamot-Rooke, N. R.; Rodriguez, M.; Petit, C.; Huchon, P.; Beslier, M.; Hazard, B.

    2009-12-01

    Since the advent of Plate Tectonics, tectonic plate boundaries were explored on land as at sea for search of active faults where the destructive energy of earthquakes is released. Yet, some plate boundaries, less active or considered as less dangerous to humankind, escaped general attention and remained unknown to a large extent. Among them, the boundary between two major tectonic plates: Arabia and India. The Arabia-India motion is currently accommodated along the Owen Fracture Zone (OFZ) in the NW Indian Ocean, which connects the spreading centers of the Sheba and Carlsberg ridge system to the Makran subduction zone. We recently surveyed this fracture zone onboard the R/V Beautemps-Beaupré (Owen Cruise, March 2009) using a high-resolution deep-water multibeam echo-sounder. Bathymetric data reveal a spectacular submarine fault system running over a distance of 800 km between the Arabia-India-Somalia triple junction to the south and the Dalrymple Trough to the north. The morphology of the active faults is well preserved on the seafloor where fault scarps can be followed over hundreds of kilometres. The surficial trace of the faults is not obscured by the sediments of the aggrading deep-sea fan of the Indus River. The fault system is segmented in five main segments connected by pull apart basins. The length of the individual, apparently uninterrupted, segments is between 100 km and 220 km. The largest pull-apart basin at the latitude 20°N (20°N-Basin) corresponds to a right step-over of about 12 km between two fault segments. The 20°N-Basin is bounded by a normal fault scarp with a throw of 450-500 m. Numerous minor normal faults cutting the floor of the basin attest to recent activity. The 20°N-Basin is directly supplied in turbidity-current deposits by an active channel of the Indus fan. The preservation of tectonic features indicates that the dip-slip motion has exceeded the rate of burial by sediments. Some compressional structures are also deduced from

  17. Fusion boundary microstructure evolution in aluminum alloys

    NASA Astrophysics Data System (ADS)

    Kostrivas, Anastasios Dimitrios

    2000-10-01

    A melting technique was developed to simulate the fusion boundary of aluminum alloys using the GleebleRTM thermal simulator. Using a steel sleeve to contain the aluminum, samples were heated to incremental temperatures above the solidus temperature of a number of alloys. In alloy 2195, a 4wt%Cu-1wt%Li alloy, an equiaxed non-dendritic zone (EQZ) could be formed by heating in the temperature range from approximately 630 to 640°C. At temperatures above 640°C, solidification occurred by the normal epitaxial nucleation and growth mechanism. Fusion boundary behavior was also studied in alloys 5454-H34, 6061-T6, and 2219-T8. Additionally, experimental alloy compositions were produced by making bead on plate welds using an alloy 5454-H32 base metal and 5025 or 5087 filler metals. These filler metals contain zirconium and scandium additions, respectively, and were expected to influence nucleation and growth behavior. Both as-welded and welded/heat treated (540°C and 300°C) substrates were tested by melting simulation, resulting in dendritic and EQZ structures depending on composition and substrate condition. Orientation imaging microscopy (OIM(TM)) was employed to study the crystallographic character of the microstructures produced and to verify the mechanism responsible for EQZ formation. OIM(TM) proved that grains within the EQZ have random orientation. In all other cases, where the simulated microstructures were dendritic in nature, it was shown that epitaxy was the dominant mode of nucleation. The lack of any preferred crystallographic orientation relationship in the EQZ supports a theory proposed by Lippold et al that the EQZ is the result of heterogeneous nucleation within the weld unmixed zone. EDS analysis of the 2195 on STEM revealed particles with ternary composition consisted of Zr, Cu and Al and a tetragonal type crystallographic lattice. Microdiffraction line scans on EQZ grains in the alloy 2195 showed very good agreement between the measured Cu

  18. A boundary term for the gravitational action with null boundaries

    NASA Astrophysics Data System (ADS)

    Parattu, Krishnamohan; Chakraborty, Sumanta; Majhi, Bibhas Ranjan; Padmanabhan, T.

    2016-07-01

    Constructing a well-posed variational principle is a non-trivial issue in general relativity. For spacelike and timelike boundaries, one knows that the addition of the Gibbons-Hawking-York (GHY) counter-term will make the variational principle well-defined. This result, however, does not directly generalize to null boundaries on which the 3-metric becomes degenerate. In this work, we address the following question: What is the counter-term that may be added on a null boundary to make the variational principle well-defined? We propose the boundary integral of 2 √{-g} ( Θ +κ ) as an appropriate counter-term for a null boundary. We also conduct a preliminary analysis of the variations of the metric on the null boundary and conclude that isolating the degrees of freedom that may be fixed for a well-posed variational principle requires a deeper investigation.

  19. 77 FR 14287 - Aspergillus flavus AF36; Amendment to an Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ...This regulation amends the existing temporary tolerance exemption for Aspergillus flavus AF36 by establishing a permanent exemption from the requirement of a tolerance for residues of the microbial pesticide, Aspergillus flavus AF36, in or on pistachio when applied as an antifungal agent and used in accordance with good agricultural practices. On behalf of the Arizona Cotton Research and......

  20. Draft Genome Sequence of Komagataeibacter intermedius Strain AF2, a Producer of Cellulose, Isolated from Kombucha Tea.

    PubMed

    Dos Santos, Renato Augusto Corrêa; Berretta, Andresa Aparecida; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues; Goldman, Gustavo H; Riaño-Pachón, Diego M

    2015-01-01

    Here, we present the draft genome sequence of Komagataeibacter intermedius strain AF2, which was isolated from Kombucha tea and is capable of producing cellulose, although at lower levels compared to another bacterium from the same environment, K. rhaeticus strain AF1. PMID:26634755

  1. Identification and Characterization of an Antifungal Protein, AfAFPR9, Produced by Marine-Derived Aspergillus fumigatus R9.

    PubMed

    Rao, Qi; Guo, Wenbin; Chen, Xinhua

    2015-05-01

    A fungal strain, R9, was isolated from the South Atlantic sediment sample and identified as Aspergillus fumigatus. An antifungal protein, AfAFPR9, was purified from the culture supernatant of Aspergillus fumigatus R9. AfAFPR9 was identified to be restrictocin, which is a member of the ribosome-inactivating proteins (RIPs), by MALDI-TOF-TOF-MS. AfAFPR9 displayed antifungal activity against plant pathogenic Fusarium oxysporum, Alternaria longipes, Colletotrichum gloeosporioides, Paecilomyces variotii, and Trichoderma viride at minimum inhibitory concentrations of 0.6, 0.6, 1.2, 1.2, and 2.4 μg/disc, respectively. Moreover, AfAFPR9 exhibited a certain extent of thermostability, and metal ion and denaturant tolerance. The iodoacetamide assay showed that the disulfide bridge in AfAFPR9 was indispensable for its antifungal action. The cDNA encoding for AfAFPR9 was cloned from A. fumigatus R9 by RTPCR and heterologously expressed in E. coli. The recombinant AfAFPR9 protein exhibited obvious antifungal activity against C. gloeosporioides, T. viride, and A. longipes. These results reveal the antifungal properties of a RIP member (AfAFPR9) from marine-derived Aspergillus fumigatus and indicated its potential application in controlling plant pathogenic fungi. PMID:25394604

  2. Draft Genome Sequence of Komagataeibacter intermedius Strain AF2, a Producer of Cellulose, Isolated from Kombucha Tea

    PubMed Central

    dos Santos, Renato Augusto Corrêa; Berretta, Andresa Aparecida; Barud, Hernane da Silva; Ribeiro, Sidney José Lima; González-García, Laura Natalia; Zucchi, Tiago Domingues

    2015-01-01

    Here, we present the draft genome sequence of Komagataeibacter intermedius strain AF2, which was isolated from Kombucha tea and is capable of producing cellulose, although at lower levels compared to another bacterium from the same environment, K. rhaeticus strain AF1. PMID:26634755

  3. Boundary layer transition studies

    NASA Technical Reports Server (NTRS)

    Watmuff, Jonathan H.

    1995-01-01

    A small-scale wind tunnel previously used for turbulent boundary layer experiments was modified for two sets of boundary layer transition studies. The first study concerns a laminar separation/turbulent reattachment. The pressure gradient and unit Reynolds number are the same as the fully turbulent flow of Spalart and Watmuff. Without the trip wire, a laminar layer asymptotes to a Falkner & Skan similarity solution in the FPG. Application of the APG causes the layer to separate and a highly turbulent and approximately 2D mean flow reattachment occurs downstream. In an effort to gain some physical insight into the flow processes a small impulsive disturbance was introduced at the C(sub p) minimum. The facility is totally automated and phase-averaged data are measured on a point-by-point basis using unprecedently large grids. The evolution of the disturbance has been tracked all the way into the reattachment region and beyond into the fully turbulent boundary layer. At first, the amplitude decays exponentially with streamwise distance in the APG region, where the layer remains attached, i.e. the layer is viscously stable. After separation, the rate of decay slows, and a point of minimum amplitude is reached where the contours of the wave packet exhibit dispersive characteristics. From this point, exponential growth of the amplitude of the disturbance is observed in the detached shear layer, i.e. the dominant instability mechanism is inviscid. A group of large-scale 3D vortex loops emerges in the vicinity of the reattachment. Remarkably, the second loop retains its identify far downstream in the turbulent boundary layer. The results provide a level of detail usually associated with CFD. Substantial modifications were made to the facility for the second study concerning disturbances generated by Suction Holes for laminar flow Control (LFC). The test section incorporates suction through interchangeable porous test surfaces. Detailed studies have been made using isolated

  4. Structural analysis of the Carolina-Inner Piedmont terrane boundary: Implications for the age and kinematics of the central Piedmont suture, a terrane boundary that records Paleozoic Laurentia-Gondwana interactions

    NASA Astrophysics Data System (ADS)

    West, Thomas E.

    1998-06-01

    New field mapping along the Carolina-Inner Piedmont terrane boundary in South Carolina and eastern Georgia reveals preaccretionary, synaccretionary, and postaccretionary faults. The dextral strike-slip Lowndesville shear zone is adjacent to a ˜50-km-long segment of the terrane boundary. However, the Lowndesville shear zone is correlated eastward with the dextral strike-slip Beaver Creek shear zone, which is within the Carolina terrane and predates ˜415 Ma. The Lowndesville shear zone is overprinted by a dextral strike-slip phyllonite zone, named the Deal Creek shear zone. The Deal Creek shear zone is correlated eastward with the Gold Hill-Silver Hill shear zone which is also within the Carolina terrane and records dextral strike-slip motion between ˜400 and ˜325 Ma. The Cross Anchor and Mulberry Creek faults both truncate the Lowndesville and the Deal Creek shear zones and form the terrane boundary. The Mulberry Creek fault, probably of Triassic-Jurassic age, juxtaposes the Lowndesville shear zone adjacent to the Carolina-Inner Piedmont terrane boundary west of Waterloo, South Carolina. The Cross Anchor fault is the terrane boundary east of Waterloo, South Carolina, and forms the southeastern boundary of the Whitmire reentrant. Crosscutting relationships indicate that the Cross Anchor fault is the oldest fault which juxtaposes the Carolina and Inner Piedmont terranes in the study area. These structural interpretations and available geochronological data indicate that the Cross Anchor fault is a ˜325 Ma thrust fault and may be the central Piedmont suture. An early Alleghanian suture resolves the problem of inserting the Carolina terrane into the western Iapetus Ocean.

  5. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  6. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  7. 40 CFR 180.1206 - Aspergillus flavus AF36; exemption from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... tolerance is established for residues of Aspergillus flavus AF36 in or on corn, field, forage; corn, field, grain; corn, field, stover; corn, field, aspirated grain fractions; corn, sweet, kernel plus cob with husk removed; corn, sweet, forage; corn, sweet, stover; corn, pop, grain; and corn, pop, stover,...

  8. Fracture Mechanics Testing of Titanium 6AL-4V in AF-M315E

    NASA Technical Reports Server (NTRS)

    Sampson, J. W.; Martinez, J.; McLean, C.

    2016-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the performance of AF-M315E monopropellant on orbit. Flight certification requires a safe-life analysis of the titanium alloy fuel tank to ensure inherent processing flaws will not cause failure during the design life of the tank. Material property inputs for this analysis require testing to determine the stress intensity factor for environment-assisted cracking (KEAC) of Ti 6Al-4V in combination with the AF-M315E monopropellant. Testing of single-edge notched, or SE(B), specimens representing the bulk tank membrane and weld material were performed in accordance with ASTM E1681. Specimens with fatigue pre-cracks were loaded into test fixtures so that the crack tips were exposed to AF-M315E at 50 C for a duration of 1,000 hours. Specimens that did not fail during exposure were opened to inspect the crack surfaces for evidence of crack growth. The threshold stress intensity value, KEAC, is the highest applied stress intensity that produced neither a failure of the specimen during the exposure nor showed evidence of crack growth. The threshold stress intensity factor for environment-assisted cracking of the Ti 6Al-4V forged tank material was found to be at least 22 ksivin and at least 31 ksivin for the weld material when exposed to AF-M315E monopropellant.

  9. K-theory of the chair tiling via AF-algebras

    NASA Astrophysics Data System (ADS)

    Julien, Antoine; Savinien, Jean

    2016-08-01

    We compute the K-theory groups of the groupoid C∗-algebra of the chair tiling, using a new method. We use exact sequences of Putnam to compute these groups from the K-theory groups of the AF-algebras of the substitution and the induced lower dimensional substitutions on edges and vertices.

  10. 28. Site Plan: AF Station P67, Fort Custer, Michigan, Plot ...

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

    28. Site Plan: AF Station P-67, Fort Custer, Michigan, Plot Plan (to accompany FY 1956 project planning report), USACOE, 22 July 1954. - Fort Custer Military Reservation, P-67 Radar Station, .25 mile north of Dickman Road, east of Clark Road, Battle Creek, Calhoun County, MI

  11. Acutangulosides A-F, monodesmosidic saponins from the bark of Barringtonia acutangula.

    PubMed

    Mills, Clive; Carroll, Anthony R; Quinn, Ronald J

    2005-03-01

    Nine triterpene saponins, acutangulosides A-F (2-7), and acutanguloside D-F methyl esters (5a-7a) and a single triterpene aglycone (1) were isolated from a water extract of the bark of Barringtonia acutangula. Their structures were assigned on the basis of spectroscopic data. PMID:15787427

  12. Dominant configurations of scintillation-producing irregularities in the auroral zone

    SciTech Connect

    Fremouw, E.J.; Lansinger, J.M.

    1981-11-01

    Recent scintillation observations have disclosed the existence of sheetlike electron density irregularities aligned along L shells in the auroral zone ionosphere. In this paper we explicit the aspect sensitivity of phase scintillation to identify the dominant three-dimensional configuration of irregularities in four latitude/time zones; (1) equatorward of the high-latitude scintillation boundary on the nightside of the earth. (2) poleward of the nightside boundary, (3) equatorward of the boundary on the day side, and (4) poleward of the dayside boundary. We find the sheetlike irregularities to be confined to region 2, with few exceptions. The dominant configuration in the other zone 4, is that of axially symmetric rodlike irregularities aligned along the magnetic field.

  13. Boundary work in knowledge teams.

    PubMed

    Faraj, Samer; Yan, Aimin

    2009-05-01

    The purpose of this article is to promote an open systems perspective on team research. The authors develop a model of team boundary activities: boundary spanning, buffering, and reinforcement. The model examines the relationship between these boundary activities and team performance, the moderating effects of organizational contextual factors, and the mediating effect of team psychological safety on the boundary work-performance relationship. These relationships were empirically tested with data collected from 64 software development teams. Boundary spanning, buffering, and boundary reinforcement were found to relate to team performance and psychological safety. Both relationships are moderated by the team's task uncertainty and resource scarcity. The implications of the findings are offered for future research and practice. PMID:19450002

  14. Boundary terms of conformal anomaly

    NASA Astrophysics Data System (ADS)

    Solodukhin, Sergey N.

    2016-01-01

    We analyze the structure of the boundary terms in the conformal anomaly integrated over a manifold with boundaries. We suggest that the anomalies of type B, polynomial in the Weyl tensor, are accompanied with the respective boundary terms of the Gibbons-Hawking type. Their form is dictated by the requirement that they produce a variation which compensates the normal derivatives of the metric variation on the boundary in order to have a well-defined variational procedure. This suggestion agrees with recent findings in four dimensions for free fields of various spins. We generalize this consideration to six dimensions and derive explicitly the respective boundary terms. We point out that the integrated conformal anomaly in odd dimensions is non-vanishing due to the boundary terms. These terms are specified in three and five dimensions.

  15. POU2AF1 Functions in the Human Airway Epithelium To Regulate Expression of Host Defense Genes.

    PubMed

    Zhou, Haixia; Brekman, Angelika; Zuo, Wu-Lin; Ou, Xuemei; Shaykhiev, Renat; Agosto-Perez, Francisco J; Wang, Rui; Walters, Matthew S; Salit, Jacqueline; Strulovici-Barel, Yael; Staudt, Michelle R; Kaner, Robert J; Mezey, Jason G; Crystal, Ronald G; Wang, Guoqing

    2016-04-01

    In the process of seeking novel lung host defense regulators by analyzing genome-wide RNA sequence data from normal human airway epithelium, we detected expression of POU domain class 2-associating factor 1 (POU2AF1), a known transcription cofactor previously thought to be expressed only in lymphocytes. Lymphocyte contamination of human airway epithelial samples obtained by bronchoscopy and brushing was excluded by immunohistochemistry staining, the observation of upregulation of POU2AF1 in purified airway basal stem/progenitor cells undergoing differentiation, and analysis of differentiating single basal cell clones. Lentivirus-mediated upregulation of POU2AF1 in airway basal cells induced upregulation of host defense genes, including MX1, IFIT3, IFITM, and known POU2AF1 downstream genes HLA-DRA, ID2, ID3, IL6, and BCL6. Interestingly, expression of these genes paralleled changes of POU2AF1 expression during airway epithelium differentiation in vitro, suggesting POU2AF1 helps to maintain a host defense tone even in pathogen-free condition. Cigarette smoke, a known risk factor for airway infection, suppressed POU2AF1 expression both in vivo in humans and in vitro in human airway epithelial cultures, accompanied by deregulation of POU2AF1 downstream genes. Finally, enhancing POU2AF1 expression in human airway epithelium attenuated the suppression of host defense genes by smoking. Together, these findings suggest a novel function of POU2AF1 as a potential regulator of host defense genes in the human airway epithelium. PMID:26927796

  16. Bisphenol AF Is a Full Agonist for the Estrogen Receptor ERα but a Highly Specific Antagonist for ERβ

    PubMed Central

    Matsushima, Ayami; Liu, Xiaohui; Okada, Hiroyuki; Shimohigashi, Miki; Shimohigashi, Yasuyuki

    2010-01-01

    Background Bisphenol AF has been acknowledged to be useful for the production of CF3-containing polymers with improved chemical, thermal, and mechanical properties. Because of the lack of adequate toxicity data, bisphenol AF has been nominated for comprehensive toxicological characterization. Objectives We aimed to determine the relative preference of bisphenol AF for the human nuclear estrogenic receptors ERα and ERβ and the bisphenol A–specific estrogen-related receptor ERRγ, and to clarify structural characteristics of receptors that influence bisphenol AF binding. Methods We examined receptor-binding activities of bisphenol AF relative to [3H]17β-estradiol (for ERα and ERβ) and [3H]bisphenol A (for ERRγ). Functional luciferase reporter gene assays were performed to assess receptor activation in HeLa cells. Results We found that bisphenol AF strongly and selectively binds to ERs over ERRγ. Furthermore, bisphenol AF receptor-binding activity was three times stronger for ERβ [IC50 (median inhibitory concentration) = 18.9 nM] than for ERα. When examined using a reporter gene assay, bisphenol AF was a full agonist for ERα. In contrast, it was almost completely inactive in stimulating the basal constitutive activity of ERβ. Surprisingly, bisphenol AF acted as a distinct and strong antagonist against the activity of the endogenous ERβ agonist 17β-estradiol. Conclusion Our results suggest that bisphenol AF could function as an endocrine-disrupting chemical by acting as an agonist or antagonist to perturb physiological processes mediated through ERα and/or ERβ. PMID:20427257

  17. Modeling the urban boundary layer

    NASA Technical Reports Server (NTRS)

    Bergstrom, R. W., Jr.

    1976-01-01

    A summary and evaluation is given of the Workshop on Modeling the Urban Boundary Layer; held in Las Vegas on May 5, 1975. Edited summaries from each of the session chairpersons are also given. The sessions were: (1) formulation and solution techniques, (2) K-theory versus higher order closure, (3) surface heat and moisture balance, (4) initialization and boundary problems, (5) nocturnal boundary layer, and (6) verification of models.

  18. TYPE AF CERTIFICATE FOR TRANSPORTATION OF LOW ENRICHED URANIUM OXIDE (LEUO) FOR DISPOSAL

    SciTech Connect

    Opperman, E; Kenneth Yates, K

    2007-10-19

    Washington Savannah River Company (WSRC) operates the Savannah River Site (SRS) in Aiken, SC under contract with the U.S. Department of Energy (DOE). SRS had the need to ship 227 drums of low enriched uranium oxide (LEUO) to a disposal site. The LEUO had been packaged nearly 25 years ago in U.S. Department of Transportation (DOT) 17C 55-gallon drums and stored in a warehouse. Since the 235U enrichment was just above 1 percent by weight (wt%) the material did not qualify for the fissile material exceptions in 49 CFR 173.453, and therefore was categorized as 'fissile material' for shipping purposes. WSRC evaluated all existing Type AF packages and did not identify any feasible packaging. Applying for a new Type AF certificate of compliance was considered too costly for a one-time/one-way shipment for disposal. Down-blending the material with depleted uranium (to reduce enrichment below 1 wt% and enable shipment as low specific activity (LSA) radioactive material) was considered, but appropriate blending facilities do not exist at SRS. After reviewing all options, WSRC concluded that seeking a DOT Special Permit was the best option to enable shipment of the material for permanent disposal. WSRC submitted the Special Permit application to the DOT, and after one request-for-additional-information (RAI) the permit was considered acceptable. However, in an interesting development that resulted from the DOT Special Permit application process, it was determined that it was more appropriate for the DOE to issue a Type AF certificate [Ref. 1] for this shipping campaign. This paper will outline the DOT Special Permit application and Type AF considerations, and will discuss the issuance of the new DOE Type AF certificate of compliance.

  19. Unraveling the Activation Mechanism of Taspase1 which Controls the Oncogenic AF4-MLL Fusion Protein.

    PubMed

    Sabiani, Samaneh; Geppert, Tim; Engelbrecht, Christian; Kowarz, Eric; Schneider, Gisbert; Marschalek, Rolf

    2015-05-01

    We have recently demonstrated that Taspase1-mediated cleavage of the AF4-MLL oncoprotein results in the formation of a stable multiprotein complex which forms the key event for the onset of acute proB leukemia in mice. Therefore, Taspase1 represents a conditional oncoprotein in the context of t(4;11) leukemia. In this report, we used site-directed mutagenesis to unravel the molecular events by which Taspase1 becomes sequentially activated. Monomeric pro-enzymes form dimers which are autocatalytically processed into the enzymatically active form of Taspase1 (αββα). The active enzyme cleaves only very few target proteins, e.g., MLL, MLL4 and TFIIA at their corresponding consensus cleavage sites (CSTasp1) as well as AF4-MLL in the case of leukemogenic translocation. This knowledge was translated into the design of a dominant-negative mutant of Taspase1 (dnTASP1). As expected, simultaneous expression of the leukemogenic AF4-MLL and dnTASP1 causes the disappearance of the leukemogenic oncoprotein, because the uncleaved AF4-MLL protein (328 kDa) is subject to proteasomal degradation, while the cleaved AF4-MLL forms a stable oncogenic multi-protein complex with a very long half-life. Moreover, coexpression of dnTASP1 with a BFP-CSTasp1-GFP FRET biosensor effectively inhibits cleavage. The impact of our findings on future drug development and potential treatment options for t(4;11) leukemia will be discussed. PMID:26137584

  20. SAMZ: Satellite-Derived Management Zones

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The term "satellite-derived management zones" (SAMZ) denotes agricultural management zones that are subdivisions of large fields and that are derived from images of the fields acquired by instruments aboard Earth orbiting satellites during approximately the past 15 years. "SAMZ" also denotes the methodology and the software that implements the methodology for creating such zones. The SAMZ approach is one of several products of continuing efforts to realize a concept of precision agriculture, which involves optimal variations in seeding, in application of chemicals, and in irrigation, plus decisions to farm or not to farm certain portions of fields, all in an effort to maximize profitability in view of spatial and temporal variations in the growth and health of crops and in the chemical and physical conditions of soils. As used here, "management zone" signifies, more precisely, a subdivision of a field within which the crop production behavior is regarded as homogeneous. From the perspective of precision agriculture, management zones are the smallest subdivisions between which the seeding, application of chemicals, and other management parameters are to be varied. In the SAMZ approach, the main sources of data are the archives of satellite imagery that have been collected over the years for diverse purposes. One of the main advantages afforded by the SAMZ approach is that the data in these archives can be reused for purposes of precision agriculture at low cost. De facto, these archives contain information on all sources of variability within a field, including weather, crop types, crop management, soil types, and water drainage patterns. The SAMZ methodology involves the establishment of a Web-based interface based on an algorithm that generates management zones automatically and quickly from archival satellite image data in response to requests from farmers. A farmer can make a request by either uploading data describing a field boundary to the Web site or else