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1

A model for observed circular polarized electric fields coincident with the passage of large seismic waves  

NASA Astrophysics Data System (ADS)

Among electric field variations supposed to be associated with earthquakes, electric field variations coincident with the passage of seismic waves have been well documented and interpreted mostly in terms of the electrokinetic effect. Here we present two examples of electric field variations obtained in association with small artificial earthquakes caused by blasting and three examples for aftershocks of two large earthquakes of magnitude 6.9 and 7.2, respectively. The electric field turned out to be circularly polarized in some cases, whereas linearly polarized cases were also seen. Since it is unclear whether such a peculiar behavior is understood in terms of existing models, we propose another mechanism to explain circular polarization; here we call this mechanism as "seismic dynamo effect," which would be regarded as an extended model of the so-called induction effect. In our model we consider ions motion in pores filled with water in the ground, which is driven by ground motion in the Earth's magnetic field. With this model we show that circular polarization of electric field is realized in association with resonance between the frequency of ground velocity due to seismic wave and the cyclotron frequency of ions, such as HCO3- or Cl- contained in pores, for the Earth's magnetic field at the observation site. Ions with positive charge, such as Na+, also seem to be responsible for circular polarization of electric field with rotation direction opposite to that for ions with negative charge. We also show that in this model the magnitude of electric field can be estimated in terms of the number density of ions.

Honkura, Y.; Ogawa, Y.; Matsushima, M.; Nagaoka, S.; Ujihara, N.; Yamawaki, T.

2009-10-01

2

Circular carrier-frequency photography for observing phase objects  

NASA Technical Reports Server (NTRS)

A circular grating is photographed through a phase object which deforms the image of the grating lines. By superimposing these deformed lines with a master grating on photographic film, moire patterns are observed. These patterns are interpreted as fringes of constant radial derivative.

Silva, D. E.; Hong, Y. M.

1972-01-01

3

Circular structures of large scale and great age on the earth's surface  

Microsoft Academic Search

It is pointed out that the earth's surface exhibits faint circular patterns which have not been described before. These circles are characterized by near perfection of outline, by the presence of topographic highs (rims) along parts of their circumferences, and by their generally large scale (diameters from 7 to 700 km). Circles of this nature have been observed clearly in

J. M. Saul

1978-01-01

4

Two-dimensional flow through large numbers of circular inhomogeneities  

NASA Astrophysics Data System (ADS)

An implicit analytic solution is presented for two-dimensional groundwater flow through a large number of non-intersecting circular inhomogeneities in the hydraulic conductivity. The locations, sizes and conductivity of the inhomogeneities may be arbitrarily selected. The influence of each inhomogeneity is expanded in a series that satisfies the Laplace equation exactly. The unknown coefficients in this expansion are related to the coefficients in the expansion of the combined discharge potential from all other elements. Using a least squares formulation for the boundary conditions and an iterative algorithm, solutions can be obtained for a very large number of inhomogeneities (e.g. 10,000) on a personal computer to any desired precision, up to the machine's limit. Such precision and speed allows the development of a numerical laboratory for investigating two-dimensional flow and convective transport.

Barnes, R.; Jankovi?, I.

1999-12-01

5

Observationally Constraining the Effects of Orbital Circularization for Stars in Binary Orbits  

NASA Astrophysics Data System (ADS)

Empirical determinations of the mass-radius-luminosity relations for main-sequence stars have, in general, used binary systems with circular orbits. However, binaries are expected to form with a wide range of primordial eccentricities and evolve towards circularity through tidal interactions. Such an evolutionary process may affect the interrelationships between mass, radius, and luminosity through tidal heating and inflation or other mechanisms. These effects may conspire to make binary systems in circularized orbits a biased source of information about single stars. The historical use of circularized binaries is due to observational restrictions, not choice. We therefore propose to obtain spectra and photometry of 9 bright and highly eccentric detached binaries as part of a program to obtain the absolute parameters of stars that have largely not undergone the processes that drive circularization. These specific targets were chosen as a pilot set to yield errors of ~ 1-2% in calculated parameters, similar to those of the best characterizations of binary systems in the literature. Using these we will directly examine the dependence of the mass, radius, and luminosity interrelationships upon circularization.

Shivvers, Isaac; Bloom, Joshua

2012-08-01

6

On internal waves generated by large-amplitude circular and rectilinear oscillations of a circular cylinder in a uniformly stratified fluid  

NASA Astrophysics Data System (ADS)

This paper presents an experimental study of internal waves generated by circular and rectilinear oscillations of a circular cylinder in a uniformly stratified fluid. The synthetic schlieren technique is used for quantitative analysis of the internal-wave parameters. It is shown that at small oscillation amplitudes, the wave pattern observed for circular oscillations is in good agreement with linear theory: internal waves are radiated in the wave beams passing through the first and third quadrants of a Cartesian coordinate system for the clockwise direction of the cylinder motion, and the intensity of these waves is twice the intensity measured for waves generated by purely horizontal or vertical oscillations of the same frequency and amplitude. As the amplitude of circular oscillations increases, significant nonlinear effects are observed: (i) a strong density-gradient disturbance is generated, and (ii) a region of intense fluid stirring is formed around the cylinder serving as an additional dissipative mechanism that changes the shape of wave envelopes and decreases the intensity of wave motions. In the same range of oscillation amplitudes, the wave generation by rectilinear (horizontal and vertical) oscillations is shown to be by and large a linear process, with moderate manifestations of nonlinearity such as weak disturbance and weak variation of the shape of wave envelopes with the oscillation amplitude. Analysis of spatiotemporal images reveals different scenarios of transient effects in the cases of circular and rectilinear oscillations. In general, circular oscillations tend to generate disturbances evolving at longer time scales.

Ermanyuk, Eugeny V.; Gavrilov, Nikolai V.

7

Large-eddy simulation of flow past a circular cylinder  

NASA Technical Reports Server (NTRS)

Some of the most challenging applications of large-eddy simulation are those in complex geometries where spectral methods are of limited use. For such applications more conventional methods such as finite difference or finite element have to be used. However, it has become clear in recent years that dissipative numerical schemes which are routinely used in viscous flow simulations are not good candidates for use in LES of turbulent flows. Except in cases where the flow is extremely well resolved, it has been found that upwind schemes tend to damp out a significant portion of the small scales that can be resolved on the grid. Furthermore, it has been found that even specially designed higher-order upwind schemes that have been used successfully in the direct numerical simulation of turbulent flows produce too much dissipation when used in conjunction with large-eddy simulation. The objective of the current study is to perform a LES of incompressible flow past a circular cylinder at a Reynolds number of 3900 using a solver which employs an energy-conservative second-order central difference scheme for spatial discretization and compare the results obtained with those of Beaudan & Moin (1994) and with the experiments in order to assess the performance of the central scheme for this relatively complex geometry.

Mittal, R.

1995-01-01

8

Synchro-Compton radiation from charges driven by circularly polarized large-amplitude plasma waves  

SciTech Connect

The spectral and angular characteristics of the power radiated by a streaming electron-positron plasma which is permeated by a circularly polarized large-amplitude hydrodynamic wave are evaluated. The modifications of the synchro-Compton process induced under these conditions are examined. Similar modifications are to be expected for more realistic large-amplitude plasma waves propagating in pulsar winds. 27 references.

Hoerhager, M.; Leubner, C.

1985-09-01

9

Improvement of Pattern Circularity of Panel Antennas Mounted on Large Towers  

Microsoft Academic Search

Three techniques using partial skew are developed in this paper. They do not lead to the same degree of smoothing of the patterns of circular arrays as the 90 °skew, but they present the advantage of being less sensitive to the presence of the supporting structure. They also provide a large flexibility in the choice of dimensions and feeding systems

Jose Perini

1968-01-01

10

Diffusion of circularly polarized light in a disordered medium with large-scale inhomogeneities  

Microsoft Academic Search

It is shown that in the presence of diffusion of electromagnetic waves in random media containing large discrete scatterers,\\u000a circular polarization can persist even after the radiation flux is isotropized. For scattering exactly in the backward direction,\\u000a this effect is manifested as an increase in the interference contribution to the cross-polarized component of the intensity\\u000a as the size of the

E. E. Gorodnichev; A. I. Kuzovlev; D. B. Rogozkin

1998-01-01

11

Large-Scale periodic solar velocities: An observational study  

NASA Technical Reports Server (NTRS)

Observations of large-scale solar velocities were made using the mean field telescope and Babcock magnetograph of the Stanford Solar Observatory. Observations were made in the magnetically insensitive ion line at 5124 A, with light from the center (limb) of the disk right (left) circularly polarized, so that the magnetograph measures the difference in wavelength between center and limb. Computer calculations are made of the wavelength difference produced by global pulsations for spherical harmonics up to second order and of the signal produced by displacing the solar image relative to polarizing optics or diffraction grating.

Dittmer, P. H.

1977-01-01

12

The use of dual channel circular-polarization radar observations for remotely sensing storm electrification  

Microsoft Academic Search

Summary Observations of thunderstorms with a dual channel circularpolarization radar have provided dramatic indications of the buildup of the electric field inside the storms and of the sudden collapse of the field at the time of lightning. The indications are obtained by coherently correlating the simultaneous returns in the right- and left-hand circular polarization channels of the radar, and follow

P. Krehbiel; T. Chen; S. McCrary; W. Rison; G. Gray; M. Brook

1996-01-01

13

A pattern recognition scheme for large curvature circular tracks and an FPGA implementation using hash sorter  

SciTech Connect

Strong magnetic field in today's colliding detectors causes track recognition more difficult due to large track curvatures. In this document, we present a global track recognition scheme based on track angle measurements for circular tracks passing the collision point. It uses no approximations in the track equation and therefore is suitable for both large and small curvature tracks. The scheme can be implemented both in hardware for lower-level trigger or in software for higher-level trigger or offline analysis codes. We will discuss an example of FPGA implementations using ''hash sorter''.

Wu, Jin-Yuan; Shi, Z.; /Fermilab

2004-12-01

14

Semi-circular microgrooves to observe active movements of individual Navicula pavillardii cells.  

PubMed

We performed a trajectory analysis of movements of Navicula pavillardii diatom cells that were confined to semi-circular microgrooves with several different curvature radii. Using the semi-circular micropattern, we succeeded in observing change of velocity of the same cell before and after the stimulation by N,N-dimethyl-p-toluidine (DMT). Because the looped grooves had longer contour length than straight grooves, it was effective to achieve the long term observation of the stimulated active cells. Although average velocity of 150 cells was significantly increased with DMT, the maximum velocity (19 ?m/s) of the cells was not increased after the DMT injection. This may suggest that existence of the mechanical limit of the velocity of the diatom cells. Secondly, trajectories of individual cell movements along the walls of the semi-circular microgrooves were analyzed in detail. As a result, the velocity of the cells was not affected by the curvature radii of the grooves although the trajectories indicated an obvious restriction of area of the cell motion. This suggests that the surface of the diatom is effective in minimizing the frictional force between the cell body and the wall of a groove. Finally, a simple model of cell motion in the semi-circular groove was proposed to clarify the relationships among the forces that determine cell movement. PMID:23337812

Umemura, Kazuo; Haneda, Takahiro; Tanabe, Masashi; Suzuki, Akira; Kumashiro, Yoshikazu; Itoga, Kazuyoshi; Okano, Teruo; Mayama, Shigeki

2013-03-01

15

Experimental study of noise emitted by circular cylinders with large roughness  

NASA Astrophysics Data System (ADS)

The aerodynamic noise generated by high Reynolds number flow around a bluff body with large surface roughness was investigated. This is a relevant problem in many applications, in particular aircraft landing gear noise. A circular cylinder in cross-flow and a zero-pressure-gradient turbulent boundary layer with various types of roughness was tested in a series of wind tunnel experiments. It has been shown that distributed roughness covering a circular cylinder affects the spectra over the entire frequency range. Roughness noise is dominant at high frequencies, and the peak frequency is well described by Howe's roughness noise model when scaled with the maximum outer velocity. There are differences between hemispherical and cylindrical roughness elements for both the circular cylinder and the zero-pressure-gradient turbulent boundary layer cases, indicating a dependence on roughness shape, not described by the considered roughness noise models. Cylindrical roughness generates higher noise levels at the highest frequencies, especially for the zero-pressure-gradient turbulent boundary layer case. Cable-type roughness aligned with the mean flow does not generate roughness noise, and its spectrum has been found to collapse with the smooth cylinder at medium and high frequencies. At low and medium frequencies the noise spectra have the same features as the smooth cylinder, but with higher shedding peak levels and fall-off levels, despite the decrease in spanwise correlation length. Roughness induces early separation, and thus a shift of the spectra to lower frequencies.

Alomar, Antoni; Angland, David; Zhang, Xin; Molin, Nicolas

2014-12-01

16

Beyond the Large Hadron Collider: a first look at cryogenics for CERN future circular colliders  

E-print Network

Following the first experimental discoveries at the Large Hadron Collider (LHC) and the recent update of the European strategy in particle physics, CERN has undertaken an international study of possible future circular colliders beyond the LHC. The study, conducted with the collaborative participation of interested institutes world-wide, considers several options for very high energy hadron-hadron, electron-positron and hadron-electron colliders to be installed in a quasi-circular underground tunnel in the Geneva basin, with a circumference of 80 km to 100 km. All these machines would make intensive use of advanced superconducting devices, i.e. high-field bending and focusing magnets and/or accelerating RF cavities, thus requiring large helium cryogenic systems operating at 4.5 K or below. Based on preliminary sets of parameters and layouts for the particle colliders under study, we discuss the main challenges of their cryogenic systems and present first estimates of the cryogenic refrigeration capacities req...

Lebrun, Ph

2014-01-01

17

Capacity of the circular plate condenser: analytical solutions for large gaps between the plates  

NASA Astrophysics Data System (ADS)

A solution of Love's integral equation (Love E R 1949 Q. J. Mech. Appl. Math. 2 428), which forms the basis for the analysis of the electrostatic field due to two equal circular co-axial parallel conducting plates, is considered for the case when the ratio, ?, of distance of separation to radius of the plates is greater than 2. The kernel of the integral equation is expanded into an infinite series in odd powers of 1/? and an approximate kernel accurate to {\\cal O}(\\tau^{-(2N+1)}) is deduced therefrom by terminating the series after an arbitrary but finite number of terms, N. The approximate kernel is rearranged into a degenerate form and the integral equation with this kernel is reduced to a system of N linear equations. An explicit analytical solution is obtained for N = 4 and the resulting analytical expression for the capacity of the circular plate condenser is shown to be accurate to {\\cal O}(\\tau^{-9}) . Analytical expressions of lower orders of accuracy with respect to 1/? are deduced from the four-term (i.e., N = 4) solution and predictions (of capacity) from the expressions of different orders of accuracy (with respect to 1/?) are compared with very accurate numerical solutions obtained by solving the linear system for large enough N. It is shown that the {\\cal O}(\\tau^{-9}) approximation predicts the capacity extremely well for any ? >= 2 and an {\\cal O}(\\tau^{-3}) approximation gives, for all practical purposes, results of adequate accuracy for ? >= 4. It is further shown that an approximate solution, applicable for the case of large distances of separation between the plates, due to Sneddon (Sneddon I N 1966 Mixed Boundary Value Problems in Potential Theory (Amsterdam: North-Holland) pp 230-46) is accurate to {\\cal O}(\\tau^{-6}) for ? >= 2.

Rao, T. V.

2005-11-01

18

Modeling large deflection of circular membranes for applications in active optical elements  

NASA Astrophysics Data System (ADS)

Our work is focused on a theoretical description and mathematical modeling of the shape of a circular edge clamped pressure actuated elastic membrane, which can be used as an optical surface of an active optical element such as the membrane lens. While the theory of small deformations of elastic membranes is well developed and the calculation of a deflection of the membrane can be done with a relatively good accuracy, modeling of large membrane deflections is more complicated. Classical approaches given in literature adopt certain approximations that affect the accuracy of the calculated shape of a membrane. In our work a generalized nonlinear differential equation describing a given problem is derived and the method for solving this equation is proposed. The numerical solution is based on the expansion of the solution into series and transformation of the problem into the constraint optimization problem. It is shown on examples that the deviation of the shape calculated using the proposed generalized equation and the classical solution is not negligible in terms of the requirements on the optical surface accuracy. The influence of the membrane shape on the optical quality of membrane fluidic lenses is also investigated.

Novák, Pavel; Novák, Ji?iacute; Mikš, Antonín.

2014-09-01

19

GEOMECHANICAL OBSERVATIONS DURING THE LARGE BLOCK TEST  

SciTech Connect

This paper presents an overview of the geomechanical studies conducted at the Large Block Test at Fran Ridge, near Yucca Mountain, Nevada. The 3-dimensional geomechanical response of the rock to heating is being monitored using instrumentation mounted in boreholes and on the surface of the block. Results show that thermal expansion of the block began a few hours after the start of heating, and is closely correlated with the thermal history. Horizontal expansion increases as a linear function of height. Comparison of observed deformations with continuum simulations shows that below the heater plane deformation is smaller than predicted, while above the heater plane, observed deformation is larger than predicted, and is consistent with opening of vertical fractures. Fracture monitors indicate that movement on a large horizontal fracture is associated with hydrothermal behavior.

STEPHEN C. BLAIR AND STEPHANIE A. WOOD

1998-04-10

20

ELF Sferics Observed at Large Distances  

NASA Astrophysics Data System (ADS)

Model predictions of the ELF radio atmospheric generated by rocket-triggered lightning are compared with observations performed at at large (>1 Mm) distances. The ability to infer source characteristics using observations at great distances may prove to greatly enhance the understanding of lightning processes that are associated with the production of transient luminous events (TLEs) as well as other ionospheric effects associated with lightning. The modeling of the sferic waveform is carried out using a modified version of the Long Wavelength Propagation Capability (LWPC) code developed by the Naval Ocean Systems Center over a period of many years. LWPC is an inherently narrowband propagation code that has been modified to predict the broadband response of the Earth-ionosphere waveguide to an impulsive lightning flash while preserving the ability of LWPC to account for an inhomogeneous waveguide. ELF observations performed in Alaska and Antarctica during rocket-triggered lightning experiments at the International Center for Lightning Research and Testing (ICLRT) located at Camp Blanding, Florida are presented. The lightning current waveforms directly measured at the base of the lightning channel (at the ICLRT) are used together with LWPC to predict the sferic waveform observed at the receiver locations under various ionospheric conditions. This paper critically compares observations with model predictions.

Dupree, N. A.; Moore, R. C.

2012-12-01

21

Observations of large transient magnetospheric electric fields  

NASA Technical Reports Server (NTRS)

Transient electric field events were observed with the long, double probe instrumentation carried by the IMP-6 satellite. Nine, clearly defined, exceptionally large amplitude events are presented here. The events are observed in the midnight sector at geocentric distances 3.5 to .5.5 R sub e at middle latitudes within a magnetic L-shell range of 4.8 to 7.5. They usually have a total duration of one to several minutes, with peak power spectra amplitudes occurring at a frequency of about 0.3 Hz. The events occur under magnetically disturbed conditions, and in most cases they can be associated with negative dH/dt excursions at magnetic observatories located near the foot of the magnetic field line intersecting IMP-6. The magnetospheric motions calculated for these electric fields indicated a quasi-stochastical diffusive process rather than the general inward magnetospheric collapsing motion expected during the expansive phases of auroral substorm activity.

Aggson, T. L.; Heppner, J. P.

1977-01-01

22

Circular High-Q Resonating Isotropic Strain Sensors with Large Shift of Resonance Frequency under Stress.  

PubMed

We present circular architecture bioimplant strain sensors that facilitate a strong resonance frequency shift with mechanical deformation. The clinical application area of these sensors is for in vivo assessment of bone fractures. Using a rectangular geometry, we obtain a resonance shift of 330 MHz for a single device and 170 MHz for its triplet configuration (with three side-by-side resonators on chip) under an applied load of 3,920 N. Using the same device parameters with a circular isotropic architecture, we achieve a resonance frequency shift of 500 MHz for the single device and 260 MHz for its triplet configuration, demonstrating substantially increased sensitivity. PMID:22303132

Melik, Rohat; Unal, Emre; Perkgoz, Nihan Kosku; Puttlitz, Christian; Demir, Hilmi Volkan

2009-01-01

23

Theory and experiments for large-amplitude vibrations of empty and fluid-filled circular cylindrical shells with imperfections  

NASA Astrophysics Data System (ADS)

The large-amplitude response of perfect and imperfect, simply supported circular cylindrical shells to harmonic excitation in the spectral neighbourhood of some of the lowest natural frequencies is investigated. Donnell's non-linear shallow-shell theory is used and the solution is obtained by the Galerkin method. Several expansions involving 16 or more natural modes of the shell are used. The boundary conditions on the radial displacement and the continuity of circumferential displacement are exactly satisfied. The effect of internal quiescent, incompressible and inviscid fluid is investigated. The non-linear equations of motion are studied by using a code based on the arclength continuation method. A series of accurate experiments on forced vibrations of an empty and water-filled stainless-steel shell have been performed. Several modes have been intensively investigated for different vibration amplitudes. A closed loop control of the force excitation has been used. The actual geometry of the test shell has been measured and the geometric imperfections have been introduced in the theoretical model. Several interesting non-linear phenomena have been experimentally observed and numerically reproduced, such as softening-type non-linearity, different types of travelling wave response in the proximity of resonances, interaction among modes with different numbers of circumferential waves and amplitude-modulated response. For all the modes investigated, the theoretical and experimental results are in strong agreement.

Amabili, M.

2003-05-01

24

Electroslag welding of the circular joints of large apparatus with localized normalizing with gas heating  

Microsoft Academic Search

With a width of heavy rolled plate of about 2 m the primary volume of welding work is the welding of circular joints. Multipass automatic welding under flux of metal of significant thickness has a low rate of productivity and is accompanied by the formation of various defects such as slag inclusions, poor penetration, and cracks in the weld metal.

A. M. Makara; I. V. Novikov; A. S. Iskra; A. E. Erinov; V. A. Sokora; I. N. Medrish; I. K. Drankovskii; V. A. Rumyantsev

1975-01-01

25

Observation of Nitrogen Polarization in Fe-N Using Soft X-ray Magnetic Circular Dichorism  

SciTech Connect

X-ray magnetic circular dichroism (XMCD) measurements were performed on epitaxial iron nitride thin films at the nitrogen K and at the Fe LIII and LII absorption edges. The iron nitride samples measured with XMCD consist primarily of {gamma}{prime} phase with no observed enhancement on their magnetic moment as compared to that of pure Fe. The XMCD difference signal between left and right elliptically polarized x rays shows a small effect in the 10{sup -5} range at the N edge, indicative of the possible polarization of nitrogen in the {gamma}{prime} Fe-N samples. XMCD spectra collected with higher energy resolution reveal the presence of multiple components in the Fe LIII absorption edge that are related to different environments for the Fe atoms, i.e., near neighbors or next near neighbors to the N sites. Finally element specific hysteresis loops were also recorded at the N and Fe absorption edges using the difference signal in various incident beam angle geometries.

Sanchez-Hanke,C.; Gonzalez-Arrabal, R.; Prieto, J.; Andrzejewska, E.; Gordillo, N.; Boerma, D.; Loloee, R.; Skuza, J.; Lukaszew, R.

2006-01-01

26

Life Cycle of a Mesoscale Circular Gust Front Observed by a C-Band Doppler Radar in West Africa  

E-print Network

Life Cycle of a Mesoscale Circular Gust Front Observed by a C-Band Doppler Radar in West Africa that occur in West Africa during the boreal summer are often associated with Afri- can easterly waves (AEWs the land surface of West Africa, with substantial surface heating leading to deep boundary layers

Guichard, Francoise

27

Experimental observations on the relationship between stagnation region flow oscillations and eddy shedding for circular cylinder  

NASA Technical Reports Server (NTRS)

Measurements indicate a direct coupling between the dominant frequencies of flow oscillations at the leading-edge stagnation region, laminar-separation unsteadiness, and the vortex shedding. An array of surface mounted, micro-thin hot-films were used to simultaneously determine the state of the boundary layer along the surfaced of a circular cylinder, and vortex shedding was monitored by a hot wire placed in its wake.

Mangalam, S. M.; Kubendran, L. R.

1990-01-01

28

Large-area broad band saturable Bragg reflectors using oxidized AlAs in the circular and inverted mesa geometries  

NASA Astrophysics Data System (ADS)

A semiconductor Saturable Bragg Reflector (SBR) is a mirror structure comprising alternating layers of high and low refractive index materials with an incorporated saturable absorber. SBRs can be used to initiate and sustain ultra-short pulses in various laser systems. In order to form ultra-short pulses, SBRs with high reflectivity over a broad wavelength range are required. Furthermore, large-area SBRs facilitate easy integration in a laser cavity. One of the key elements for the realization of broad band SBRs is the development of the thermal oxidation process that creates buried low-index AlxOy layers over large areas. The design, fabrication, characterization, and implementation of broad band, high index contrast III-V/AlxOy SBRs in the form of circular mesas, as well as inverted mesa structures, is presented.

Nabanja, Sheila P.; Kolodziejski, Leslie A.; Petrich, Gale S.; Sander, Michelle Y.; Morse, Jonathan L.; Shtyrkova, Katia; Ippen, Erich P.; Kärtner, Franz X.

2013-04-01

29

An Observation of a Circular Motion using Ordinary Appliances: Train Toy, Digital Camera, and Android based Smartphone  

E-print Network

Using a digital camera (Sony DSC-S75) in its video mode and a smartphone (Samsung GT-N700) equipped with an acceleration sensor, observation of a uniform circular motion of a toy train (Thomas & Friends, Player World, CCF No. 2277-13) is conducted. From the first observation average centripetal acceleration about 0.154 m/s2 is obtained, while the second gives 0.350 m/s2 of average centripetal acceleration by assuming ideal condition, where measured accelerations in z direction is not interpreted.

Viridi, Sparisoma; Nasri, Meldawati

2013-01-01

30

Launch window analysis of satellites in high eccentricity or large circular orbits  

NASA Technical Reports Server (NTRS)

Numerical methods and computer programs for studying the stability and evolution of orbits of large eccentricity are presented. Methods for determining launch windows and target dates are developed. Mathematical models are prepared to analyze the characteristics of specific missions.

Renard, M. L.; Bhate, S. K.; Sridharan, R.

1973-01-01

31

Measurement of nonlinear observables in the Large Hadron Collider using kicked beams  

NASA Astrophysics Data System (ADS)

The nonlinear dynamics of a circular accelerator such as the Large Hadron Collider (LHC) may significantly impact its performance. As the LHC progresses to more challenging regimes of operation it is to be expected that the nonlinear single particle dynamics in the transverse planes will play an increasing role in limiting the reach of the accelerator. As such it is vital that the nonlinear sources are well understood. The nonlinear fields of a circular accelerator may be probed through measurement of the amplitude detuning: the variation of tune with single particle emittance. This quantity may be assessed experimentally by exciting the beam to large amplitudes with kicks, and obtaining the tunes and actions from turn-by-turn data at Beam Position Monitors. The large amplitude excitations inherent to such a measurement also facilitate measurement of the dynamic aperture from an analysis of beam losses following the kicks. In 2012 these measurements were performed on the LHC Beam 2 at injection energy (450 GeV) with the nominal magnetic configuration. Nonlinear coupling was also observed. A second set of measurements were performed following the application of corrections for b4 and b5 errors. Analysis of the experimental results, and a comparison to simulation are presented herein.

Maclean, E. H.; Tomás, R.; Schmidt, F.; Persson, T. H. B.

2014-08-01

32

Large eddy simulations of a circular orifice jet with and without a cross-sectional exit plate  

NASA Astrophysics Data System (ADS)

The effect of a cross-sectional exit plane on the downstream mixing characteristics of a circular turbulent jet is investigated using large eddy simulation (LES). The turbulent jet is issued from an orifice-type nozzle at an exit Reynolds number of 5×104. Both instantaneous and statistical velocity fields of the jet are provided. Results show that the rates of the mean velocity decay and jet spread are both higher in the case with the exit plate than without it. The existence of the plate is found to increase the downstream entrainment rate by about 10% on average over the axial range of 8-30de (exit diameter). Also, the presence of the plate enables the formation of vortex rings to occur further downstream by 0.5-1.0de. A physical insight into the near-field jet is provided to explain the importance of the boundary conditions in the evolution of a turbulent jet. In addition, a method of using the decay of the centreline velocity and the half-width of the jet to calculate the entrainment rate is proposed.

Zhang, Jian-Peng; Xu, Min-Yi; Mi, Jian-Chun

2014-04-01

33

Transition from progressive buckling to global bending of circular shells under axial impact––Part I: Experimental and numerical observations  

Microsoft Academic Search

The influence of impact velocity and material characteristics on the dynamic buckling response of circular shells subjected to axial impact loads is studied. It is shown experimentally that the critical buckling length, which marks the transition between progressive and global buckling of aluminium alloy circular tubes, is significantly influenced by the axial impact velocity. A finite element analysis is undertaken

D. Karagiozova; Marc??lio Alves

2004-01-01

34

Impingement heat transfer and recovery effect with submerged jets of large Prandtl number liquid—I. Unconfined circular jets  

Microsoft Academic Search

Experimental study was performed to characterize recovery factor and heat transfer coefficient on vertical heaters impinged by submerged circular transformer oil jets issued from both pipe and orifice nozzles. Radial distributions of local recovery factor were determined at various Reynolds numbers and nozzle-to-plate spacings, and compared with numerical result. Local Nusselt number at stagnation point was found to be proportional

T. Gomi; Q. ZHENG; S. C. LEE

1997-01-01

35

Observations of Large Amplitude, Narrowband Whistlers at Stream Interaction Regions  

NASA Astrophysics Data System (ADS)

We present the first solar wind observations of large amplitude, narrowband waveforms in the whistler frequency range 10-100 Hz. Amplitudes range from a few to >40 mV/m peak-to-peak, one to three orders of magnitude larger than any previous observations of whistler mode waves in the solar wind. The whistlers are obliquely propagating with a large electrostatic component and are right-hand elliptically polarized in the spacecraft frame. They occur in groups that are strongly correlated with stream interaction regions. The groups persist from a few seconds to minutes and are observed at 88% of SIRs and 17% of shocks from available data. A more detailed look shows that the whistler groups are observed near sudden disturbances of the solar wind magnetic field and plasma. Test particle simulations indicate that these whistlers may play an important role in the dynamics of solar wind electrons within SIRs and near some shocks.

Breneman, Aaron; Cattell, C.; Kersten, K.; Wilson, L., III; Schreiner, S.; Jian, L.; Kellogg, P.; Goetz, K.

2010-11-01

36

Large deployable reflectors for telecom and earth observation applications  

NASA Astrophysics Data System (ADS)

Large deployable antennas are one of the key components for advanced missions in the fields of telecom and earth observation. In the recent past, missions have taken on board large deployable reflector (LDR) up to 22 m of diameter and several missions have already planned embarking large reflectors, such as the 12 m of INMARSAT XL or BIOMASS. At the moment, no European LDR providers are available and the market is dominated by Northrop-Grumman and Harris. Consequently, the development of European large reflector technology is considered a key step to maintain commercial and strategic competitiveness (ESA Large Reflector Antenna Working Group Final Report, TEC-EEA/2010.595/CM, 2010). In this scenario, the ESA General Study Project RESTEO (REflector Synergy between Telecom and Earth Observation), starting from the identification of future missions needs, has identified the most promising reflector concepts based on European heritage/technology, able to cover the largest range of potential future missions for both telecom and earth observation. This paper summarizes the activities and findings of the RESTEO Study.

Scialino, L.; Ihle, A.; Migliorelli, M.; Gatti, N.; Datashvili, L.; 't Klooster, K.; Santiago Prowald, J.

2013-12-01

37

On tidal tilt corrections to large ring laser gyroscope observations  

NASA Astrophysics Data System (ADS)

With the fast development of the large ring laser gyroscope (RLG) technology in the last decades, promising applications in geophysics and geodesy (e.g. observations of high-frequency variations of Earth's rotation, Earth's tide tilt and seismic waves) have been realized by various groups with currently running large RLGs. In this letter, we point out that in a large number of previous tilt correction models a significant term is missing. This term is related with the Shida number l2 (called l2-term in the following) and has a contribution, which is comparable with that from high-frequency Earth rotation variations due to ocean tides, to the Sagnac frequency record of RLGs. This term has to be removed (as part of the tilt correction) from the raw data so that RLGs can efficiently be employed as Earth's rotation detectors.

Tian, Wei

2014-01-01

38

Circular polarization of twilight.  

NASA Technical Reports Server (NTRS)

Review of observations of circular polarization of twilight performed with a polarimeter which uses an electronically switched Pockels cell operated as a reversible quarter-wave plate to convert circular into linear polarization. The latter was then analyzed by a Wollaston prism followed by two gallium-arsenide photomultipliers. The discovery of a definite natural circular polarization at twilight does suggest that, with increased observation precision, measurements of the small daylight component are possible. These could give useful information about particles in the atmosphere and be valuable in studies of meteorology and air pollution.

Angel, J. R. P.; Illing, R.; Martin, P. G.

1972-01-01

39

Interferometric observations of large biologically interesting interstellar and cometary molecules  

PubMed Central

Interferometric observations of high-mass regions in interstellar molecular clouds have revealed hot molecular cores that have substantial column densities of large, partly hydrogen-saturated molecules. Many of these molecules are of interest to biology and thus are labeled “biomolecules.” Because the clouds containing these molecules provide the material for star formation, they may provide insight into presolar nebular chemistry, and the biomolecules may provide information about the potential of the associated interstellar chemistry for seeding newly formed planets with prebiotic organic chemistry. In this overview, events are outlined that led to the current interferometric array observations. Clues that connect this interstellar hot core chemistry to the solar system can be found in the cometary detection of methyl formate and the interferometric maps of cometary methanol. Major obstacles to understanding hot core chemistry remain because chemical models are not well developed and interferometric observations have not been very sensitive. Differentiation in the molecular isomers glycolaldehdye, methyl formate, and acetic acid has been observed, but not explained. The extended source structure for certain sugars, aldehydes, and alcohols may require nonthermal formation mechanisms such as shock heating of grains. Major advances in understanding the formation chemistry of hot core species can come from observations with the next generation of sensitive, high-resolution arrays. PMID:16894168

Snyder, Lewis E.

2006-01-01

40

Observations of Bipolar Molecular Outflows with Large Millimeter Arrays  

NASA Astrophysics Data System (ADS)

The ejection of a bipolar outflow is a central phenomenon in the processes by which a new star is formed, and the molecular component of such outflows is particularly interesting because of its large mass, momentum, and energy, and because it contains information about all the past mass-loss episodes from the central engine. This paper illustrates the fact that the research on bipolar molecular outflows has progressed thanks to the increase in angular resolution of the available instrumentation. I stress the importance of observing bipolar outflows with large millimeter arrays, and conclude that a millimeter-wave array providing an angular resolution of 0.1" will solve many of the challenging questions on outflows which remain open nowadays.

Bachiller, R.

41

Satellite observations of large power plants and megacities from GOSAT  

NASA Astrophysics Data System (ADS)

Fossil fuel CO2 emissions are a major source of CO2 to the global carbon cycle over decadal time scales and international efforts to curb those missions are required for mitigating climate change. Although emissions from nations are estimated and reported to help monitor their compliance of emission reductions, we still lack an objective method to monitor emissions directly. Future carbon-observing space missions are thus expected to provide an independent tool for directly measuring emissions. We proposed and have implemented satellite observations specifically over intense large point sources (LPS), including large fossil-fueled power plants and megacities, worldwide (N > 300) using the Japanese Greenhouse Gases Observing SATelllite (GOSAT). Our target LPS sites have been occasionally included in the observation schedule of GOSAT and the measurements are made using the target observation mode. This proposal was officially accepted by the GOSAT project office and we have attempted to use these data to detect signatures of man-made greenhouse gas emissions. We have submitted our locations of interest on a monthly basis two month prior to observation. We calculated the X_CO2 concentration enhancement due to the LPS emissions. We analyzed GOSAT X_CO2 retrievals from four research groups (five products total): the National Institute for Environmental Studies (NIES) (both the NIES standard Level 2 and NIES-PPDF products), the NASA Atmospheric CO2 from Space (ACOS) team (ACOS Level 2 product), the Netherlands Institute for Space Research (SRON)/Karlsruhe Institute of Technology, Germany (RemoTeC), and the University of Leicester, UK (Full-Physics CO2 retrieval dataset). Although we obtained fewer retrieved soundings relative to what we requested (probably due to geophysical difficulties in the retrievals), we did obtain statistically significant enhancements at some LPS sites where weather condition were ideal for viewing. We also implemented simulations of enhanced X_CO2 using a global Eulerian-Lagrangian coupled atmospheric transport model (GELCA) and a high-resolution fossil fuel emissions dataset (Odiac). Odiac includes emissions information on the power plants requested in our target observations. Our model simulations tend to underestimate the enhancements, but showed good correlation with observed enhancements.

Oda, Tom; Maksyutov, Shamil; Boesch, Hartmut; Butz, Andre; Ganshin, Alexander; Guerlet, Sandrine; Parker, Robert; O'Dell, Chris; Oshchepkov, Sergey; Yoshida, Yukio; Zhuravlev, Ruslan; Yokota, Tatsuya

2013-04-01

42

Observation of pellet ablation behaviour on the Large Helical Device  

NASA Astrophysics Data System (ADS)

Hydrogen ice pellets have been injected using two different location configurations, namely outer port injection and coil side injection, in the large helical device. The behaviour of the pellet ablation has been observed using a fast camera, which possesses high spatial and time resolution. Striking toroidal deflection of the pellet trajectory is observed. The deflection is in the direction of tangential neutral beam injection. The toroidal velocity ultimately reaches 1000 m s-1 or more. The possibility of a rocket effect due to a unilateral ablation by the fast ions is discussed. The effective penetration depth of the pellet, which is measured by images, agrees with the prediction from the neutral-gas-shielding model. The penetration depth is compared with the measured deposition profile of the pellet.

Sakamoto, R.; Yamada, H.; Tanaka, K.; Tokuzawa, T.; Murakami, S.; Goto, M.; Morita, S.; Ohyabu, N.; Kawahata, K.; Motojima, O.; LHD Experimental Group

2004-05-01

43

Observation of large-amplitude magnetosonic waves at dipolarization fronts  

NASA Astrophysics Data System (ADS)

plasma waves have been observed in the vicinity of dipolarization fronts (DFs) and the rarefaction regions behind them. It was suggested that these waves not only play crucial roles in regulating particle kinetics at the DFs but also may potentially affect the large-scale dynamics of the magnetotail. In this paper, we present the observations of large-amplitude electromagnetic waves at DFs that occurred during magnetospheric substorms. The DFs were embedded in either the tailward or earthward flows in the near-Earth magnetotail. The wave frequencies were near the local proton cyclotron frequency. The waves propagated at highly oblique angles with respect to the ambient magnetic field (~80°-100°). Their corresponding wavelengths were on the order of the local ion gyroradii. The major magnetic field fluctuations were along the background magnetic field, while the electric field fluctuations were predominantly perpendicular to the background magnetic field. The waves were compressional waves as there was an anticorrelation between the plasma density and the wave magnetic field strength. The electric potential associated with the waves reached to more than half of the electron temperature, indicating the waves are nonlinear. We suggest that the waves were magnetosonic or ion Bernstein mode waves driven by the ion ring distribution. The waves were able to provide significant anomalous resistivity at the front, with major contributions from the electric field fluctuations. The effects of these waves on the electron pitch angle scattering and energy diffusion are also discussed.

Zhou, Meng; Ni, Binbin; Huang, Shiyong; Deng, Xiaohua; Ashour-Abdalla, Maha; Nishimura, Yukitoshi; Yuan, Zhigang; Pang, Ye; Li, Huimin

2014-06-01

44

Observation of an unusually large atomic parity-violation effect  

NASA Astrophysics Data System (ADS)

We report on observation of a large parity-violation effect in the atoms of ytterbium (Yb). This left-right asymmetry appears naturally in the Standard Model, and is associated with the exchange of a virtual heavy ``gauge" boson between subatomic particles. Eventually, parity violation has been observed and precisely measured by a number of groups in several different atoms, culminating in a 0.3% measurement in cesium (Cs) by Carl Wieman and co-workers at Boulder. The parity-violating amplitude of the 6x^2 ^1S0 -> 5d6s ^3D1 408-nm forbidden transition of ytterbium is found to be two orders of magnitude larger than in cesium. This is the largest atomic parity-violating amplitude yet observed. This also opens the way to future measurements of the parity violation effects for different Yb isotopes in order to test the effect of the neutron distributions within the nucleus and detect the so-called ``anapole moment" by comparing parity-violating amplitudes for various hyperfine components of the transition. So far, Cs is the only system where such a moment has been detected. Measurements of anapole moments are important for understanding the electroweak interactions within the nucleus which are hard to probe by other means.

Tsigutkin, Konstantin

2010-03-01

45

Circular questioning.  

PubMed

The plan of this paper is to explore the question: Does a model that includes the principles of double description, circularity, and coevolutionary change, all accounting for shifts in family coalitions over time and the emergence of problems in connection with these shifts, allow the family therapist to design better methods for the understanding and practice of family therapy? Concepts of double description, coevolution, and circularity from Gregory Bateson's writing and the research of other scientists describe the translation of these ideas from pure epistemology to the pragmatics of family therapy. Circular questioning developed by the Milan Associates is presented as a practice method exemplifying how these notions of circularity and coevolutionary change--especially changes in family patterns--are used during actual family sessions. PMID:7128764

Penn, P

1982-09-01

46

Circular Mesa  

NASA Technical Reports Server (NTRS)

MGS MOC Release No. MOC2-538, 8 November 2003

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a circular mesa in northeast Arabia Terra. The circularity suggests that this landform might be similar to other circular mesas, found elsewhere on Mars. In those other cases, the mesa was once a meteor impact crater. The crater was filled with sediment, the sediment was cemented to become rock, and later erosion removed all of the material surrounding the former crater, leaving it standing alone as a circular mesa. This image is located near 23.7oN, 319.0oW, and covers an area 3 km (1.9 mi) wide. The scene is illuminated by sunlight from the left.

2003-01-01

47

Evaluation of forest fire models on a large observation database  

NASA Astrophysics Data System (ADS)

This paper presents the evaluation of several fire propagation models using a large set of observed fires. The observation base is composed of 80 Mediterranean fire cases of different sizes, which come with the limited information available in an operational context (burned surface and approximative ignition point). Simulations for all cases are carried out with 4 different front velocity models. The results are compared with several error scoring methods applied to each of the 320 simulations. All tasks are performed in a fully automated manner, with simulations ran as first guesses with no tuning for any of the models or cases. This approach leads a wide range of simulation performance, including some of the bad simulation results to be expected in an operational context. Regardless the quality of the input data, it is found that the models can be ranked based on their performance and that the most complex models outperform the more empirical ones. Data and source code used for this paper are freely available to the community.

Filippi, J.-B.; Mallet, V.; Nader, B.

2014-05-01

48

Large Scale Constraints on Methane Emissions Determined from Observations  

NASA Astrophysics Data System (ADS)

Measurements of atmospheric CH4 from the NOAA Global Monitoring Division's, Global Cooperative Air Sampling Network began in 1983. These high-precision observations offer key constraints on CH4's budget including the global burden, the rate of increase, and the spatial distribution of CH4 at the surface. These observations allow estimates of total global CH4 emissions without using a chemical transport model. A surprising result of this analysis is that, if the CH4 lifetime has been constant, then total global emissions have been approximately constant since the mid-1980s. This result is difficult to reconcile with bottom-up inventories that report increasing anthropogenic emissions, unless natural emissions have decreased considerably. Analysis of anomalies in CH4 growth rate also allow us to test our understanding of the processes that affect the atmospheric CH4 burden. Large anomalies have been attributed to decreased CH4 sink after the eruption of Mt. Pinatubo in 1992, decreased emissions from wetlands because of cooler than normal temperatures in 1992, and increased emissions from biomass burning and wetlands in 1997/98. The most recent anomaly, starting in 2007 and continuing into early-2011 with an average rate of increase of ~6 ppb yr-1, is more persistent than previous ones and may indicate a permanent change to the global CH4 budget. Dlugokencky et al. [Geophys. Res. Lett., 36, 2009] attributed the increases in 2007 and 2008 to anomalously high temperatures in the Arctic (2007) and greater than average precipitation in the tropics (2007 and 2008). Continuing increases in 2009 and 2010 may be related to a very strong La Niña starting in 2010, the same climate pattern responsible for large positive precipitation anomalies in tropical wetland regions in 2007 and 2008. Indeed, strong precipitation anomalies were observed in SE Asia during 2010. This is a likely cause of continued CH4 increase, and it is consistent with the observation that the largest growth rates in 2010 were in the southern tropics. For 2009, when we were in a weak El Niño, no clear cause has emerged. The observations indicate the largest growth rates were observed in mid-latitudes of the northern hemisphere, a departure from 2007, 2008, and 2010 when signals were clearly dominated by the tropics. A recent model study by Bousquet et al. (Atmos. Chem. Phys., 11, 3689-3700, 2011) is consistent with our earlier study on the role of tropical and high northern latitude wetlands in increased CH4 growth during 2007, but unclear as to the causes of increase in 2008. Little additional information about the causes of the recent anomaly has been determined from satellite retrievals of CH4 column abundance (Frankenberg et al., J. Geophys. Res., 116, 2011).

Dlugokencky, E. J.; Lang, P.; Masarie, K.; Crotwell, A. M.; Bruhwiler, L.

2011-12-01

49

The Flux of Large Meteoroids Observed with Lunar Impact Monitoring  

NASA Technical Reports Server (NTRS)

The flux of large meteoroids is not well determined due to relatively low number statistics, due mainly to the lack of collecting area available to meteor camera systems (10(2)-10(5) km2). Larger collecting areas are needed to provide reasonable statistics for flux calculations. The Moon, with millions of square kilometers of lunar surface, can be used as a detector for observing the population of large meteoroids in the tens of grams to kilogram mass range. This is accomplished by observing the flash of light produced when a meteoroid impacts the lunar surface, converting a portion of its kinetic energy to visible light detectable from Earth. A routine monitoring program at NASA's Marshall Space Flight Center has recorded over 300 impact flashes since early 2006. The program utilizes multiple 0.35 m (14 inch) Schmidt-Cassegrain telescopes, outfitted with video cameras using the 1/2 inch Sony EXview HAD CCDTM chip, to perform simultaneous observations of the earthshine hemisphere of the Moon when the lunar phase is between 0.1 and 0.5. This optical arrangement permits monitoring of approximately 3.8x10(6) km2 of lunar surface. A selection of 126 flashes recorded in 266.88 hours of photometric skies was analyzed, creating the largest and most homogeneous dataset of lunar impact flashes to date. Standard CCD photometric techniques outlined in [1] were applied to the video to determine the luminous energy, kinetic energy, and mass for each impactor, considering a range of luminous efficiencies. The flux to a limiting energy of 2.5x10(-6) kT TNT or 1.05×10(7) J is 1.03×10(-7) km(-2) hr(-1) and the flux to a limiting mass of 30 g is 6.14×10(-10) m(-2) yr(-1). Comparisons made with measurements and models of the meteoroid population indicate that the flux of objects in this size range is slightly lower (but within the error bars) than the power law distribution determined for the near Earth object population by [2].

Cooke, W. J.; Suggs, R. M.; Moser, D. E.; Suggs, R. J.

2014-01-01

50

Observation of magnetic circular dichroism in resonant inelastic x-ray scattering at the {ital L}{sub 3} edge of gadolinium metal  

SciTech Connect

Magnetic circular dichroism is observed in inelastic x-ray scattering from {ital d} core electrons in magnetically aligned gadolinium at incident photon energies resonant with the Gd 2{ital p}{sub 3/2} excitations. The dichroism is dominated by the magnetic interactions between the valence 4{ital f} electrons and the final state {ital d} core hole. Unlike photoabsorption spectroscopy, but similar to core photoelectron spectroscopy, this method allows one to probe electron-correlation effects in the valence ground-state population. {copyright} {ital 1996 The American Physical Society.}

Krisch, M.H.; Sette, F.; Bergmann, U.; Masciovecchio, C.; Verbeni, R.; Goulon, J. [European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble Cedex (France)] [European Synchrotron Radiation Facility, Boite Postale 220, F-38043 Grenoble Cedex (France); Caliebe, W.; Kao, C.C. [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973 (United States)

1996-11-01

51

Six Large Coronal X-ray Flares Observed With Chandra  

E-print Network

A study of the six largest coronal X-ray flares in the Chandra archive is presented. The flares were observed on II Peg, OU And, Algol, HR 1099, TZ CrB and CC Eri, all with the High Energy Transmission Grating spectrometer (HETG) and the ACIS detectors. We reconstruct an Emission Measure Distribution EMD(T), using a spectral line analysis method, for flare and quiescence states separately and compare the two. Subsequently, elemental abundaces are obtained from the EMD. We find similar behaviour of the EMD in all flares, namely a large high-T component appears while the low-T (kT < 2 keV) plasma is mostly unaffected, except for a small rise in the low-T Emission Measure. In five of the six flares we detect a First Ionization Potential (FIP) effect in the flare abundances relative to quiescence. This may contradict previous suggestions that flares are the cause of an inverse FIP effect in highly active coronae.

R. Nordon; E. Behar

2006-11-13

52

Sequence and organization of large subunit rRNA genes from the extrachromosomal 35 kb circular DNA of the malaria parasite Plasmodium falciparum.  

PubMed

The malaria parasite Plasmodium falciparum carries an extrachromosomal 35 kb circular DNA molecule of unknown provenance. A striking feature of the circle is a palindromic sequence of genes for subunit rRNAs and several tRNAs, spanning ca. 10.5 kb. The palindrome has an intriguing resemblance to the inverted repeat of plastid genomes, and the sequence and putative secondary structure of the malarial large subunit (LSU) rRNA described in this report were used as the basis of a phylogenetic study. The malarial rRNA was found to be highly divergent in comparison with a selected group of chloroplast LSU rRNAs but was more closely related to them than to mitochondrial LSU rRNA genes. PMID:8464693

Gardner, M J; Feagin, J E; Moore, D J; Rangachari, K; Williamson, D H; Wilson, R J

1993-03-11

53

Large breast compressions: Observations and evaluation of simulations  

SciTech Connect

Purpose: Several methods have been proposed to simulate large breast compressions such as those occurring during x-ray mammography. However, the evaluation of these methods against real data is rare. The aim of this study is to learn more about the deformation behavior of breasts and to assess a simulation method. Methods: Magnetic resonance (MR) images of 11 breasts before and after applying a relatively large in vivo compression in the medial direction were acquired. Nonrigid registration was employed to study the deformation behavior. Optimal material properties for finite element modeling were determined and their prediction performance was assessed. The realism of simulated compressions was evaluated by comparing the breast shapes on simulated and real mammograms. Results: Following image registration, 19 breast compressions from 8 women were studied. An anisotropic deformation behavior, with a reduced elongation in the anterior-posterior direction and an increased stretch in the inferior-superior direction was observed. Using finite element simulations, the performance of isotropic and transverse isotropic material models to predict the displacement of internal landmarks was compared. Isotropic materials reduced the mean displacement error of the landmarks from 23.3 to 4.7 mm, on average, after optimizing material properties with respect to breast surface alignment and image similarity. Statistically significantly smaller errors were achieved with transverse isotropic materials (4.1 mm, P=0.0045). Homogeneous material models performed substantially worse (transverse isotropic: 5.5 mm; isotropic: 6.7 mm). Of the parameters varied, the amount of anisotropy had the greatest influence on the results. Optimal material properties varied less when grouped by patient rather than by compression magnitude (mean: 0.72 vs 1.44). Employing these optimal materials for simulating mammograms from ten MR breast images of a different cohort resulted in more realistic breast shapes than when using established material models. Conclusions: Breasts in the prone position exhibited an anisotropic compression behavior. Transverse isotropic materials with an increased stiffness in the anterior-posterior direction improved the prediction of these deformations and produced more realistic mammogram simulations from MR images.

Tanner, Christine; White, Mark; Guarino, Salvatore; Hall-Craggs, Margaret A.; Douek, Michael; Hawkes, David J. [Centre of Medical Image Computing, UCL, London WC1E 6BT, United Kingdom and Computer Vision Laboratory, ETH Zuerich, 8092 Zuerich (Switzerland); Centre of Medical Image Computing, UCL, London WC1E 6BT (United Kingdom); Department of Surgery, UCL, London W1P 7LD (United Kingdom); Department of Imaging, UCL Hospital, London NW1 2BU (United Kingdom); Department of Surgery, UCL, London W1P 7LD (United Kingdom); Centre of Medical Image Computing, UCL, London WC1E 6BT (United Kingdom)

2011-02-15

54

Observations Regarding Small Eolian Dunes and Large Ripples on Mars  

NASA Technical Reports Server (NTRS)

Eolian bedforms occur at the interface between a planetary surface and its atmosphere; they present a proxy record of the influence of climate, expressed in sediment transport, over that surface. High resolution images (1.5 - 12 m/pixel) from the Mars Global Surveyor (MGS) Mars Orbiter Camera provide glimpses of the most recent events shaping the martian landscape. Thousands of images exhibit small transverse dunes or large eolian ripples that have crest-to-crest spacings of 10 to 60 m, heights of a few to 10 m. Bedforms of the size and patterns seen in the Mars photographs are rarely described among Earth's eolian landforms; in terms of size and morphology, most of these fall between traditional definitions of "ripples" and "dunes". Dunes are composed chiefly of materials transported by saltation, ripples are smaller forms moved along by the impact of saltating grains (traction). The largest reported eolian ripples on Earth (granule ripples, megaripples) are typically smaller than the bedforms observed on Mars; likewise, most dunes are typically larger. The small dunes and large ripples on Mars come in a variety of relative albedos, despite an early MGS impression that they are all of high albedo. Some ripples occur on the surfaces of sand dunes; these are most likely true granule ripples. However, most of these bedforms occur in troughs, pits, craters, and on deflated plains. Despite impressions early in the MGS mission, they do not occur everywhere (e.g., they are rare on the northern plains) but they do occur at a range of elevations from the highest volcanoes to the deepest basins. Where they occur on a hard substrate among larger sand dunes, the big dunes have over-ridden the smaller bedforms, indicating that the smaller features are older and perhaps indurated or very coarse-grained. At other locales, the small bedforms have been mantled by material settled from suspension, in other cases they are being exhumed and may be lithified. Still other examples are peppered with small impact craters, implying considerable age. These bedforms present a complicated record of the geologically-recent past, one that has involved changes in climate, sediment transport capabilities, and sediment sources and sinks over time.

Edgett, Kenneth S.

2001-01-01

55

Parametric analysis of an ion propulsion system for performing large inclination changes in low Earth circular orbits  

Microsoft Academic Search

An analytical model has been constructed for an ion propulsion system which performs large changes in the inclination of a satellite in low-earth orbit. A thrusting strategy and the top-level propulsion system design are also presented. The analytical model enables the derivation of requirements for ?V, propellant, and power. A parametric trade study is presented which explores the relationship of

B. Jackson; Greg Hoffman

1991-01-01

56

Advisory Circular  

Microsoft Academic Search

1. PURPOSE. This advisory circular (AC) contains references to the minimum requirements for the selection and performance of aircraft rescue and firefighting personal protective equipment (PPE), self contained breathing apparatus (SCBA), and powered rescue tools. This AC is designed to assist airport management in the development of local procurement specifications for airport fire departments. Equipment meeting the standards in this

2008-01-01

57

Cluster observations of hot flow anomalies with large flow deflections  

NASA Astrophysics Data System (ADS)

Case and statistical studies have been performed to investigate hot flow anomalies (HFAs) with large flow deflections using the Cluster-C1 spacecraft data from 2003 to 2009. We have selected 87 events with Vy or Vz in GSE coordinates larger than 200 km\\ s-1. Observations of these HFAs indicate a "Location Dependent Deflection": Vy or Vz deflects to a positive value when the event is located in the positive Y or Z side relative to the sub-solar point, and to a negative value when it is located in the negative Y or Z side relative to the sub-solar point; the amplitude of the deflection increases with the increasing distance in Y or Z direction; the decrease in Vx at the event center is larger when the location is closer to the Sun-Earth line. The "Location Dependent Deflection" might be due to a near-specularly reflection of ions at the Earth's bow shock. The results also suggest that HFAs can be formed at both quasi-parallel and quasi-perpendicular shocks. The HFAs studied in this paper are close to the bow shock with the distance from the event to the bow shock ranging from 0.03 to 3.51 RE, which might help the reflected ions remain as a coherent near-specular reflected beam. In addition, HFAs with both edges at quasi-perpendicular shocks are closer to the bow shock than those with both edges at quasi-parallel shocks. This might help the reflected ions at a quasi-perpendicular shock interact with the incident solar wind immediately after the reflection and increase the possibility of HFA formation. The HFAs with both the leading and trailing edges at quasi-perpendicular shocks show a high gyration velocity and a high fast magneto-sonic Mach number, increasing the gyro-radius and the possibility of pitch angle scattering, which might help the ions escape from the bow shock and move upstream.

Wang, S.; Zong, Q.; Zhang, H.

2012-12-01

58

Interstellar circular polarization.  

NASA Technical Reports Server (NTRS)

This paper shows that optical observations of circular polarization produced by aligned interstellar grains could yield valuable information about the grain material. The interstellar medium is known to be linearly dichroic from observations of interstellar linear polarization. Since the same aligned grains make the medium linearly birefringent, a small component of circular polarization can result from incident linearly polarized light if the position angle of the linear polarization does not coincide with either principal axis of the medium. Calculations demonstrate that the wavelength of the circular polarization is sensitive to the imaginary part of the complex refractive index of the grain material. This provides an opportunity of investigating whether the grains are characteristically dielectric or metallic.

Martin, P. G.

1972-01-01

59

Elliptic and circular wormholes  

E-print Network

Two new exact analytical solutions of the euclidean Einstein equations for a minimal massless scalar field and negative cosmological constant have been obtained. These solutions are given in terms of Jacobian elliptic or circular functions, rather than hyperbolic functions, connect large asymptotic regions of maximally-symmetric anti-DeSitter metrics through a microscopic throat, and correspond to negative definite components of the Ricci tensor. Therefore, they describe wormhole-like changes of topology driven by nucleation of baby universes. The quantum state of such elliptic and circular wormholes or handles is discussed in the most interesting inner and asymptotic regions.

P. F. González-Díaz

1993-06-25

60

Circular beams.  

PubMed

A very general beam solution of the paraxial wave equation in circular cylindrical coordinates is presented. We call such a field a circular beam (CiB). The complex amplitude of the CiB is described by either the Whittaker functions or the confluent hypergeometric functions and is characterized by three parameters that are complex in the most general situation. The propagation through complex ABCD optical systems and the conditions for square integrability are studied in detail. Special cases of the CiB are the standard, elegant, and generalized Laguerre-Gauss beams; Bessel-Gauss beams; hypergeometric beams; hypergeometric-Gaussian beams; fractional-order elegant Laguerre-Gauss beams; quadratic Bessel-Gauss beams; and optical vortex beams. PMID:18197231

Bandres, Miguel A; Gutiérrez-Vega, Julio C

2008-01-15

61

Importance of C*-H based modes and large amplitude motion effects in vibrational circular dichroism spectra: the case of the chiral adduct of dimethyl fumarate and anthracene.  

PubMed

The role played by the C*-H based modes (C* being the chiral carbon atom) and the large amplitude motions in the vibrational absorption (VA) and vibrational circular dichroism (VCD) spectra is investigated. The example of an adduct of dimethyl fumarate and anthracene, i.e., dimethyl-(+)-(11R,12R)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylate, and two deuterated isotopomers thereof specially synthesized for this goal, are considered. By comparing the experimental and DFT calculated spectra of the undeuterated and deuterated species, we demonstrate that the C*-H bending, rocking, and stretching modes in the VA and VCD spectra are clearly identified in well defined spectroscopic features. Further, significant information about the conformer distribution is gathered by analyzing the VA and VCD data of both the fingerprint and the C-H stretching regions, with particular attention paid to the band shape data. Effects related to the large amplitude motions of the two methoxy moieties have been simulated by performing linear transit (LT) calculations, which consists of varying systematically the relative positions of the two methoxy moieties and calculating VCD spectra for the partially optimized structures obtained in this way. The LT method allows one to improve the quality of calculated spectra, as compared to experimental results, especially in regard to relative intensities and bandwidths. PMID:24840313

Passarello, Marco; Abbate, Sergio; Longhi, Giovanna; Lepri, Susan; Ruzziconi, Renzo; Nicu, Valentin Paul

2014-06-19

62

Large Scale Surface Radiation Budget from Satellite Observation  

NASA Technical Reports Server (NTRS)

During the current reporting period, the focus of our work was on preparing and testing an improved version of our Surface Radiation Budget algorithm for processing the ISCCP D1 data routinely at the SRB Satellite Data Analysis Center (SDAC) at NASA Langley Research Center. The major issues addressed are related to gap filling and to testing whether observations made from ERBE could be used to improve current procedures of converting narrowband observations, as available from ISCCP, into broadband observations at the TOA. The criteria for selecting the optimal version are to be based on results of intercomparison with ground truth.

Pinker, R. T.

1995-01-01

63

SEARCH Workshop on Large-Scale Atmosphere/Cryosphere Observations  

NASA Technical Reports Server (NTRS)

The purpose of the workshop held in Seattle during 27-29 November 2001 was to review existing land, sea ice, and atmospheric observations and the prospect for an Arctic System Reanalysis, through white papers, invited speakers, and panels. A major task for SEARCH was to determine how existing observation systems can be best used and enhanced to understand and anticipate the course of the ongoing changes in the Arctic. The primary workshop conclusion is that there is no cohesion among various Arctic disciplines and data types to form a complete observation set of Arctic change; a second workshop conclusion is that present data sets are vastly underutilized in understanding Arctic change; a third conclusion is that a distributed observing system must accommodate a wide range of spatial patterns of variability.

2002-01-01

64

Accumulation of large non-circular forms of the chromosome in recombination-defective mutants of Escherichia coli  

PubMed Central

Background Double-strand breakage of chromosomal DNA is obviously a serious threat to cells because various activities of the chromosome depend on its integrity. However, recent experiments suggest that such breakage may occur frequently during "normal" growth in various organisms – from bacteria through vertebrates, possibly through arrest of a replication fork at some endogenous DNA damage. Results In order to learn how the recombination processes contribute to generation and processing of the breakage, large (> 2000 kb) linear forms of Escherichia coli chromosome were detected by pulsed-field gel electrophoresis in various recombination-defective mutants. The mutants were analyzed in a rich medium, in which the wild-type strain showed fewer of these huge broken chromosomes than in a synthetic medium, and the following results were obtained: (i) Several recB and recC null mutants (in an otherwise rec+ background) accumulated these huge linear forms, but several non-null recBCD mutants (recD, recC1001, recC1002, recC1003, recC1004, recC2145, recB2154, and recB2155) did not. (ii) In a recBC sbcA background, in which RecE-mediated recombination is active, recA, recJ, recQ, recE, recT, recF, recO, and recR mutations led to their accumulation. The recJ mutant accumulated many linear forms, but this effect was suppressed by a recQ mutation. (iii) The recA, recJ, recQ, recF and recR mutations led to their accumulation in a recBC sbcBC background. The recJ mutation showed the largest amount of these forms. (iv) No accumulation was detected in mutants affecting resolution of Holliday intermediates, recG, ruvAB and ruvC, in any of these backgrounds. Conclusion These results are discussed in terms of stepwise processing of chromosomal double-strand breaks. PMID:12718760

Handa, Naofumi; Kobayashi, Ichizo

2003-01-01

65

MESSENGER Observations of Large Flux Transfer Events at Mercury  

NASA Technical Reports Server (NTRS)

Six flux transfer events (FTEs) were encountered during MESSENGER's first two flybys of Mercury (MI and M2). For MI the interplanetary magnetic field (IMF) was predominantly northward and four FTEs with durations of 1 to 6 s were observed in the magnetosheath following southward 1M F turnings. The IMF was steadily southward during M2, and an FTE 4 s in duration was observed just inside the dawn magnetopause followed approx.32 s later by a 7-s FTE in the magnetosheath. Flux rope models were fit to the magnetic field data to detem11ne PTE dimensions and flux content The largest FTE observed by MESSENGER had a diameter of approx. 1 R(sub M) (where R(sub M) is Mercury's radius), and its open magnetic field increased the fraction of the surface exposed to the solar wind by 10 - 20 percent and contributed up to approx.30 kV to the cross-magnetospheric electric potential.

Slavin, James A.; Lepping, Ronald P.; Wu, Chin-Chun; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Killen, Rosemary M.; Korth, Haje; Krimigis, Stamatios M.; McClintock, William E.; McNutt, Ralph L., Jr.; Sarantos, Menelaos; Schriver, David; Solomon, Sean C.; Travnicek, Pavel; Zurbuchen, Thomas H.

2010-01-01

66

MESSENGER Observations of Large Flux Transfer Events at Mercury  

NASA Technical Reports Server (NTRS)

Six flux transfer events (FTEs) were encountered during MESSENGER's first two flybys of Mercury (M1 and M2). For M1 the interplanetary magnetic field (IMF) was predominantly northward and four FTEs with durations of 1 to 6 s were observed in the magnetosheath following southward IMF turnings. The IMF was steadily southward during M2, and an FTE 4 s in duration was observed just inside the dawn magnetopause followed approx. 32 s later by a 7 s FTE in the magnetosheath. Flux rope models were fit to the magnetic field data to determine FTE dimensions and flux content. The largest FTE observed by MESSENGER had a diameter of approx. 1 R(sub M) (where R(sub M) is Mercury s radius), and its open magnetic field increased the fraction of the surface exposed to the solar wind by 10 - 20 percent and contributed up to approx. 30 kV to the cross-magnetospheric electric potential.

Slavin, James A.; Lepping, Ronald P.; Wu, Chin-Chun; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Boardsen, Scott A.; Killen, Rosemary M.; Korth, Haje; Krimigis, Stamatios M.; McClintock, William E.; McNutt, Ralph L., Jr.; Sarantos, Menelaos; Schriver, David; Solomon, Sean C.; Travnicek, Pavel; Zurbuchen, Thomas H.

2010-01-01

67

Life Cycle of a Mesoscale Circular Gust Front Observed by a C-Band Doppler Radar in West Africa  

E-print Network

On 10 July 2006, during the Special Observation Period (SOP) of the African Monsoon Multidisciplinary Analysis (AMMA) campaign, a small convective system initiated over Niamey and propagated westward in the vicinity of ...

Lothon, Marie

68

Sufficient observables for large-scale structure in galaxy surveys  

NASA Astrophysics Data System (ADS)

Beyond the linear regime, the power spectrum and higher order moments of the matter field no longer capture all cosmological information encoded in density fluctuations. While non-linear transforms have been proposed to extract this information lost to traditional methods, up to now, the way to generalize these techniques to discrete processes was unclear; ad hoc extensions had some success. We pointed out in Carron and Szapudi's paper that the logarithmic transform approximates extremely well the optimal `sufficient statistics', observables that extract all information from the (continuous) matter field. Building on these results, we generalize optimal transforms to discrete galaxy fields. We focus our calculations on the Poisson sampling of an underlying lognormal density field. We solve and test the one-point case in detail, and sketch out the sufficient observables for the multipoint case. Moreover, we present an accurate approximation to the sufficient observables in terms of the mean and spectrum of a non-linearly transformed field. We find that the corresponding optimal non-linear transformation is directly related to the maximum a posteriori Bayesian reconstruction of the underlying continuous field with a lognormal prior as put forward in the paper of Kitaura et al.. Thus, simple recipes for realizing the sufficient observables can be built on previously proposed algorithms that have been successfully implemented and tested in simulations.

Carron, J.; Szapudi, I.

2014-03-01

69

Observation and Simulation of Large-scale Deformation of Tongue  

Microsoft Academic Search

To develop a physiological articulatory model for speech production, mastication and swallowing, we proposed an analysis-by-synthesis (AbS) based estimation method for investigating contributions of the tongue muscles in both exterior movement and interior deformation using observations and model simulations. The validity of the method was confirmed by comparing the estimated muscle activation to known muscle activation via model simulation using

Jianwu DANG; Satoru FUJITA; Emi MURANO; Maureen STONE

70

Cosmological Parameter Estimation with Large Scale Structure Observations  

E-print Network

We estimate the sensitivity of future galaxy surveys to cosmological parameters, using the redshift dependent angular power spectra of galaxy number counts, $C_\\ell(z_1,z_2)$, calculated with all relativistic corrections at first order in perturbation theory. We pay special attention to the redshift dependence of the non-linearity scale and present Fisher matrix forecasts for Euclid-like and DES-like galaxy surveys. We compare the standard $P(k)$ analysis with the new $C_\\ell(z_1,z_2)$ method. We show that for surveys with photometric redshifts the new analysis performs significantly better than the $P(k)$ analysis. For spectroscopic redshifts, however, the large number of redshift bins which would be needed to fully profit from the redshift information, is severely limited by shot noise. We also identify surveys which can measure the lensing contribution and we study the monopole, $C_0(z_1,z_2)$.

Di Dio, Enea; Durrer, Ruth; Lesgourgues, Julien

2014-01-01

71

Large-scale convection patterns observed by DMSP  

SciTech Connect

The authors present a comprehensive compilation of the average distribution of the electrostatic potential across the high-latitude ionosphere. The averages are compiled from potentials along the satellite path calculated from thermal ion drift data from instrumentation on the Defense Meterological Satellite Program (DMSP) flights 8 and 9 satellites. Data were collected from the DMSP F8 satellite during the period September 1987 to December 1990 and from the DMSP F9 satellite during the period March 1988 to December 1990. The potential distributions are separated by geomagnetic position, season, and orientation of the interplanetary magnetic field (IMF), and then averages of the distributions are calculated. The average potential distributions clearly show the displacement of polar cap convection contours to the dusk or dawk flanks under the influence of the IMF B{sub y} component. The cross-cap potential decreases as IMF B{sub z} changes from southward to northward. The average distributions indicate that the development of more than two convection cells for northward IMF is either uncommon or nonexistent. For IMF B{sub z} > 0 and B{sub z} >{vert_bar}B{sub y}{vert_bar}, a distorted pattern is observed in the average potential distribution, not a four-cell pattern as some previous studies suggest it should be. For all orientations of the IMF, the convection reversal boundary at the poleward edge of the auroral zone is observed in the average distributions to be a rotational boundary. It is not a shear boundary as suggested by some previous investigations. On average, the Harang discontinuity (convection reversal in the auroral zone near midnight) is observed to exist weakly or not at all. When examining individual passes, a strong eastward flow is present sometimes in the region of the Harang discontinuity, especially on the poleward boundary, but not at all times as implied by the Heppner-Maynard model. 39 refs., 9 figs., 2 tabs.

Rich, F.J. [Hanscom Air Force Base, Bedford, MA (United States)] [Hanscom Air Force Base, Bedford, MA (United States); Hairston, M. [Univ. of Texas, Dallas, TX (United States)] [Univ. of Texas, Dallas, TX (United States)

1994-03-01

72

Large-scale convection patterns observed by DMSP  

NASA Astrophysics Data System (ADS)

We present a comprehensive compilation of the average distribution of the electrostatic potential across the high-latitude ionosphere. The averages are compiled from potential along the satellite path calculated from thermal ion drift data from instrumentation on the Defense Meteorological Satellite Program (DMSP) flights 8 and 9 satellites. Data were collected from the DMSP F8 satellite during the period September 1987 to December 1990 and from the DMSP F9 satellite during the period March 1988 to December 1990. The potential distributions are separated by geomagnetic position, season, and orientation of the interplanetary magnetic field (IMF), and then averages of the distributions are calculated. The average potential distributions clearly show the displacement of polar cap convection contours to the dusk or dawn flanks under the influence of the IMF B(sub y) component. The cross-cap potential decreases as IMF B(sub z) changes from southward to northward. The average distributions indicate that the development of more than two convection cells for northward IMF is either uncommon or nonexistent. For IMF B(sub z) greater than 0 and B(sub z) greater than the absolute value of B(sub y), a distorted pattern is observed in the average potential distribution, not a four-cell pattern as some previous studies suggest it should be. For all orientations of the IMF, the convection reversal boundary at the poleward edge of the auroral zone is observed in the average distributions to be a rotational boundary. It is not a shear boundary as suggested by some previous investigations. On average, the Harang discontinuity (convection reversal in the auroral zone near midnight) is observed to exist weakly or not at all. When examining individual passes, a strong eastward flow is present sometimes in the region of the Harang discontinuity, especially on the poleward boundary, but not at all times as implied by the Heppner-Maynard model.

Rich, Frederick J.; Hairston, Marc

1994-03-01

73

Observation of a turbulence-induced large scale magnetic field.  

PubMed

An axisymmetric magnetic field is applied to a spherical, turbulent flow of liquid sodium. An induced magnetic dipole moment is measured which cannot be generated by the interaction of the axisymmetric mean flow with the applied field, indicating the presence of a turbulent electromotive force. It is shown that the induced dipole moment should vanish for any axisymmetric laminar flow. Also observed is the production of toroidal magnetic field from applied poloidal magnetic field (the omega effect). Its potential role in the production of the induced dipole is discussed. PMID:16486942

Spence, E J; Nornberg, M D; Jacobson, C M; Kendrick, R D; Forest, C B

2006-02-10

74

Interactive analysis of a large aperture Earth observations satellite  

NASA Technical Reports Server (NTRS)

A system level design and analysis has been conducted on an Earth Observation Satellite (EOS) system using the Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) computer-aided design and analysis program. The IDEAS program consists of about 40 user-friendly technical modules and an interactive graphics display. The reflector support system and feed mast of the EOS spacecraft are constructed with box-truss structural concept, a lattice configuration which can be packaged for delivery in a single Shuttle flight and deployed in orbit. The deployed spacecraft consists of a 120-m by 60-m parabolic focal axis. The spacecraft was modeled for structural, thermal, and control systems analysis and structural elements were designed. On-orbit dynamic and thermal loading analyses were conducted; spacecraft weights and developmental and first unit costs were determined.

Wright, R. L.; Deryder, D. D.; Ferebee, M. J., Jr.; Smith, J. C.

1983-01-01

75

Observations of large scale ion conic generation with DE-1  

SciTech Connect

Data from Dynamics Explorer 1 were analyzed to investigate the phenomena that are associated with the occurrence of upward conical ion distributions in the nightside auroral oval. In a single pass through the boundary plasma sheet (BPS) and central plasma sheet (CPS) at altitudes near 1 R/sub E/ and MLT of about 19 hrs, it was found that the angular morphology of the conics contained distinct signatures of the parallel and perpendicular flow velocities that were determined from calculated moments of the ion-distribution functions. In addition to the expected presence of field-aligned currents and waves in the <100-Hz frequency range, the CPS conic region, where the highest-energy conics were observed, contained a population of upward-streaming electrons with temperatures between 1 and 2 eV. It is suggested that the upward-streaming electrons may be the primary source of free energy for ion conic generation.

Winningham, J.D.; Burch, J.L.

1984-01-01

76

Circular RNA Is Expressed across the Eukaryotic Tree of Life  

PubMed Central

An unexpectedly large fraction of genes in metazoans (human, mouse, zebrafish, worm, fruit fly) express high levels of circularized RNAs containing canonical exons. Here we report that circular RNA isoforms are found in diverse species whose most recent common ancestor existed more than one billion years ago: fungi (Schizosaccharomyces pombe and Saccharomyces cerevisiae), a plant (Arabidopsis thaliana), and protists (Plasmodium falciparum and Dictyostelium discoideum). For all species studied to date, including those in this report, only a small fraction of the theoretically possible circular RNA isoforms from a given gene are actually observed. Unlike metazoans, Arabidopsis, D. discoideum, P. falciparum, S. cerevisiae, and S. pombe have very short introns (?100 nucleotides or shorter), yet they still produce circular RNAs. A minority of genes in S. pombe and P. falciparum have documented examples of canonical alternative splicing, making it unlikely that all circular RNAs are by-products of alternative splicing or ‘piggyback’ on signals used in alternative RNA processing. In S. pombe, the relative abundance of circular to linear transcript isoforms changed in a gene-specific pattern during nitrogen starvation. Circular RNA may be an ancient, conserved feature of eukaryotic gene expression programs. PMID:24609083

Wang, Peter L.; Bao, Yun; Yee, Muh-Ching; Barrett, Steven P.; Hogan, Gregory J.; Olsen, Mari N.; Dinneny, Jose R.; Brown, Patrick O.; Salzman, Julia

2014-01-01

77

Large-scale Observations of the Magnetopause by Cluster  

NASA Astrophysics Data System (ADS)

The magnetopause and its adjacent boundary layers are a key science target for many satellite missions. They have been sampled, at the same time, either locally by a maximum of 4 to 5 closely spaced spacecraft (from the Cluster constellation and the Double Star TC-1 satellite) or on larger scales by missions such as Geotail, Cluster and THEMIS. Unfortunately, none of the spacecraft configurations has so far permitted the 'evolution' of perturbations along their main direction of propagation to be tracked. The study of the evolution of magnetic field and plasma perturbations, such as Kelvin-Helmholtz (KH) waves or Flux Transfer Events (FTEs), together with the (associated or not) generation of Kinetic Alfvén Waves (KAWs) and the turbulence developing at the flank magnetopause boundary layer, is important for our understanding of the mechanisms that mediate solar wind plasma entry into the magnetosphere, i.e. magnetic reconnection and diffusive processes. The Cluster Guest Investigator (GI) proposal implemented in November 2012 targeted inter-spacecraft separations of ~1 RE necessary to relate disturbances and deduce their evolution. It resulted in separations of up to 36,000 km across the constellation at the magnetopause and was the largest separation ever for the Cluster mission. In this invited talk, I will present the first results from the Cluster GI observations of magnetopause boundary layer.

Foullon, Claire

2014-05-01

78

Classification of Circular Features on Venus  

NASA Technical Reports Server (NTRS)

Among the unanswered questions concerning Venus are the age of its surface and the mechanisms of lithospheric heat transfer (conduction, plate recycling, and hot spot volcanism). If there is a large population of impact craters, then the surface is ancient and Venus is characterized by conduction like the Moon, and Mercury, rather than plate recycling and hot spot volcanism. Alternatively, if there is a large population of volcanic craters, then the surface is younger and other mechanisms of heat transfer likely dominate. Previous studies have emphasized various aspects of the observational, theoretical, experimental, and comparative planetological studies of cratering on Venus, and several have reached divergent opinions concerning the age of the Venus surface. A major source of uncertainty in previous studies is the possible inclusion of circular features of nonimpact (volcanic or tectonic) origin in the so called impact crater population. A classification scheme of circular features on Venus is developed in order to further distinguish their origin and distribution.

Stofan, E. R.; Head, J. W.; Grieve, R. A. F.

1985-01-01

79

Interstellar circular polarization and the composition of interstellar dust  

NASA Technical Reports Server (NTRS)

This paper shows that optical observations of circular polarization produced by aligned interstellar grains could yield valuable information about the grain material. The interstellar medium is known to be linearly dichroic from observations of interstellar linear polarization; many different grain models using a large variety of compositions can be found to reproduce these observations. Since the same aligned grains make the medium linearly birefringent, a small component of circular polarization can result from incident linearly polarized light if the position angle of the linear polarization does not coincide with either principal axis of the medium. Here calculations are presented to demonstrate that the wavelength of the circular polarization is sensitive to the imaginary part of the complex refractive index of the grain material. This provides an opportunity of investigating whether the grains are characteristically dielectric or metallic. Some possible observations are suggested.

Martin, P. G.

1973-01-01

80

Circular differential scattering and circular differential absorption of DNA-protein condensates and of dyes bound to DNA-protein condensates  

SciTech Connect

DNA-protein condensates that give positive and negative psi-type circular dichroism (CD) spectra (psi condensates) bind intercalative and nonintercalative dyes. CD depends both on circular differential scattering and on circular differential absorption; scattering-corrected CD measurements are approximations to circular differential absorption. The circular differential scattering and scattering-corrected CD patterns observed in the DNA absorption band of psi condensates are mimicked in the induced CD band of intercalators bound to psi condensates. The induced scattering-corrected CD and circular differential scattering patterns of the groove-binding dye Hoechst 33342 bound to psi condensates are the inverse of the patterns seen with intercalative dyes, whereas the groove-binding dye manganese(III) meso-tetrakis(4-N-methylpyridyl)porphine (MnIIITMpyP-4) shows no significant induced CD patterns. The large circular differential scattering and scattering-corrected CD bands are interpreted as resulting from long-range chiral packing, rather than near-neighbor short-range interactions. Dyes intercalated into the DNA of the psi condensates have the same type of long-range chiral packing as the DNA bases. Therefore, the psi-type CD spectra seen in the UV spectra originating from the long-range packing of the DNA bases are also observed in the visible spectra when dyes are intercalated in the DNA of the psi condensates. Our interpretation comes from the observation that the induced circular differential scattering and circular differential absorption of the dye bound to the psi condensates depend only upon the sign of the circular differential absorption and the pattern of the circular differential scattering of the psi condensates without bound dye.

Phillips, C.L.; Mickols, W.E.; Maestre, M.F.; Tinoco, I. Jr.

1986-12-02

81

The Formaldehyde Masers in Sgr B2: Very Long Baseline Array and Very Large Array Observations  

E-print Network

Observations of two of the formaldehyde (H2CO) masers (A and D) in Sgr B2 using the VLBA+Y27 (resolution ~0.01") and the VLA (resolution ~9") are presented. The VLBA observations show compact sources (10^8 K. The maser sources are partially resolved in the VLBA observations. The flux densities in the VLBA observations are about 1/2 those of the VLA; and, the linewidths are about 2/3 of the VLA values. The applicability of a core-halo model for the emission distribution is demonstrated. Comparison with earlier H2CO absorption observations and with ammonia (NH3) observations suggests that H2CO masers form in shocked gas. Comparison of the integrated flux densities in current VLA observations with those in previous observations indicates that (1) most of the masers have varied in the past 20 years, and (2) intensity variations are typically less than a factor of two compared to the 20-year mean. No significant linear or circular polarization is detected with either instrument.

Ian M. Hoffman; W. M. Goss; Patrick Palmer

2006-09-28

82

Experimental investigation of heat transfer in turbulent flow of air in a circular tube with large temperature drop and cooling of the air  

Microsoft Academic Search

An experimental investigation has been made of the influence of the temperature factor on the heat transfer coefficient in cooling of air in a circular tube. It has been shown that in the developed-turbulence section the heat transfer coefficient does not depend on the value of the temperature factor, when the latter is decreased to 0.12. The problem of heat

V. I. Rozhdestvenskii

1969-01-01

83

Review of circular tank technology and management  

Microsoft Academic Search

Large cost savings have been achieved in the production of food fish with the use of larger systems and enhanced production management strategies. These trends have also included the use of large circular culture tanks because of their many advantages for food fish production. Circular tanks make good culture vessels because they can provide a uniform culture environment, can be

Michael B. Timmons; Steven T. Summerfelt; Brian J. Vinci

1998-01-01

84

Large electric field at the nightside plasmapause observed by the Polar spacecraft  

E-print Network

Click Here for Full Article Large electric field at the nightside plasmapause observed by the Polar; accepted 16 June 2010; published 21 July 2010. [1] We report an example of large electric field with a peak amplitude of 60 mV/m observed at the plasmapause by the Polar spacecraft on April 25, 1998. This electric

California at Berkeley, University of

85

Circular polarization ratio characteristics of impact craters from Mini-RF observations and implications for ice detection at the polar regions of the Moon  

NASA Astrophysics Data System (ADS)

In an attempt to reduce the ambiguity on radar detection of water ice at the permanently shadowed regions near the lunar poles, radar echo strength and circular polarization ratio (CPR) of impact craters are analyzed using the Miniature Radio Frequency (Mini-RF) radar data from the Lunar Reconnaissance Orbiter mission. Eight typical craters, among over 70 craters, are selected and classified into four categories based on their locations and CPR characteristics: polar anomalous, polar fresh, nonpolar anomalous, and nonpolar fresh. The influences on CPR caused by surface slope, rocks, and dielectric constant are analyzed quantitatively using high-resolution topography data and optical images. A two-component mixed model for CPR that consists of a normal surface and a rocky surface is developed to study the effect of rocks that are perched on lunar surface and buried in regolith. Our analyses show that inner wall of a typical bowl-shaped crater can give rise to a change of about 30° in local incidence angle of radar wave, which can further result in a CPR difference of about 0.2. There is a strong correlation between Mini-RF CPR and rock abundance that is obtained from high-resolution optical images, and predictions from the two-component mixed model match well with the observed CPRs and the estimated rock abundances. Statistical results show that there is almost no apparent difference in CPR characteristics between the polar and nonpolar anomalous craters, or between the polar and nonpolar fresh craters. The enhanced CPR in the interior of anomalous craters is most probably caused by rocks that are perched on lunar surface or buried in regolith, instead of ice deposits as suggested in previous studies.

Fa, Wenzhe; Cai, Yuzhen

2013-08-01

86

An observer for a deployable antenna. [for large space structure flight experiment  

NASA Technical Reports Server (NTRS)

An observer is derived for use on an Orbiter-Deployable Antenna configuration. The unique feature of this observer design for this flight experiment is that all the plant inputs are not required to be directly accessible for the observer to ferret out the system states. The observer uses state and rate of the state information to reconstruct the plant states. Results are presented which show how effectively this observer design works for this large space structure flight experiment.

Waites, H. B.

1981-01-01

87

Large-Amplitude Internal Waves Observed off the Northwest Coast of Sumatra  

Microsoft Academic Search

Internal waves of large amplitude were observed north of Sumatra by the U.S. Coast & Geodetic Survey ship Pioneer in June 1984. The bathythermograph investigation which defined these waves was initiated after observation of curious periodic surface phe- nomena resembling tide rips. Analysis of bathythermograph records indicates that internal waves with a maximum observed wave height of 82 meters are

Richard B. Perry

1965-01-01

88

Method for digitizing paper archive of solar radio observations made with Large Pulkovo Radio Telescope  

NASA Astrophysics Data System (ADS)

Valuable large archive of solar radio observations has been accumulated by the Pulkovo solar radio group. But big part of data is recorded on paper. We describe a method and software for transferring data recorded on paper to FITS format.

Abramov-Maximov, Vladimir E.

89

A Large-Scale Study of MySpace: Observations and Implications for Online Social Networks  

E-print Network

A Large-Scale Study of MySpace: Observations and Implications for Online Social Networks James the characteristics of large online social net- works through an extensive analysis of over 1.9 mil- lion MySpace profiles in an effort to understand who is using these networks and how they are being used. We study MySpace

Caverlee, James

90

Mechanical and hydrologic basis for the rapid motion of a large tidewater glacier. 1: Observations  

Microsoft Academic Search

Measurements of glacier flow velocity and basal water pressure at two sites on Columbia Glacier, Alaska, are combined with meteorological and hydrologic data to provide an observational basis for assessing the role of water storage and basal water pressure in the rapid movement of this large glacier. During the period from July 5 to August 31, 1987, coordinated observations were

Mark Meier; Scott Lundstrom; Dan Stone; Barclay Kamb; Hermann Engelhardt; Neil Humphrey; William W. Dunlap; Mark Fahnestock; Robert M. Krimmel; Roy Walters

1994-01-01

91

Detection of large scale electron density irregularities during IPS observations at 103 MHz  

Microsoft Academic Search

Angular displacements in the positions of the quasar 3C 298 were observed during its interplanetary scintillation (IPS) observations made using a correlation interferometer at 103 MHz at Thaltej near Ahmedabad. Two possibilities which might cause such effects are considered; refraction of the radio waves either in the earth's ionosphere or in the interplanetary medium (IPM) by large scale plasma density

S. K. Alurkar; H. O. Vats; R. V. Bhonsle; A. K. Sharma

1985-01-01

92

Fault detection of large scale wind turbine systems: A mixed H?\\/H? index observer approach  

Microsoft Academic Search

This paper addresses the fault detection issue of large scale wind turbine systems. The underlying problem is very critical to enhance the reliability and reduce the cost of maintenance of wind turbines. In this work, mixed Hinfin\\/H- index observer is utilized to generate the residual for fault detection purpose. The employed observer is optimal in the sense that it is

Xiukun Wei; Michel Verhaegen

2008-01-01

93

A LEKID-based CMB instrument design for large-scale observations in Greenland  

NASA Astrophysics Data System (ADS)

We present the results of a feasibility study, which examined deployment of a ground-based millimeter-wave polarimeter, tailored for observing the cosmic microwave background (CMB), to Isi Station in Greenland. The instrument for this study is based on lumped-element kinetic inductance detectors (LEKIDs) and an F/2.4 catoptric, crossed-Dragone telescope with a 500 mm aperture. The telescope is mounted inside the receiver and cooled to < 4 K by a closed-cycle 4He refrigerator to reduce background loading on the detectors. Linearly polarized signals from the sky are modulated with a metal-mesh half-wave plate that is rotated at the aperture stop of the telescope with a hollow-shaft motor based on a superconducting magnetic bearing. The modular detector array design includes at least 2300 LEKIDs, and it can be configured for spectral bands centered on 150 GHz or greater. Our study considered configurations for observing in spectral bands centered on 150, 210 and 267 GHz. The entire polarimeter is mounted on a commercial precision rotary air bearing, which allows fast azimuth scan speeds with negligible vibration and mechanical wear over time. A slip ring provides power to the instrument, enabling circular scans (360 degrees of continuous rotation). This mount, when combined with sky rotation and the latitude of the observation site, produces a hypotrochoid scan pattern, which yields excellent cross-linking and enables 34% of the sky to be observed using a range of constant elevation scans. This scan pattern and sky coverage combined with the beam size (15 arcmin at 150 GHz) makes the instrument sensitive to 5 < ` < 1000 in the angular power spectra.

Araujo, D. C.; Ade, P. A. R.; Bond, J. R.; Bradford, K. J.; Chapman, D.; Che, G.; Day, P. K.; Didier, J.; Doyle, S.; Eriksen, H. K.; Flanigan, D.; Groppi, C. E.; Hillbrand, Seth N.; Johnson, B. R.; Jones, G.; Limon, Michele; Miller, A. D.; Mauskopf, P.; McCarrick, H.; Mroczkowski, T.; Reichborn-Kjennerud, B.; Smiley, B.; Sobrin, Joshua; Wehus, I. K.; Zmuidzinas, J.

2014-08-01

94

Circular Polarized LCD  

Microsoft Academic Search

Novel LCD, which transmits circularly polarized light, is reported. The circular polarized light enables us to see the LCD screen through polarized sunglasses. It is developed for outdoor application, such as mobile computing, car navigator, and so on. The circular light is achieved by placing additional quarter wave film upon the screen.

Hideo Takano; Yuhji Yoshida

1998-01-01

95

Circular Dichroism Spectra of Granal and Agranal Chloroplasts of Maize  

PubMed Central

Granum-containing chloroplasts from mesophyll cells of maize (Zea mays L. var. MV 861) leaves exhibited circular dichroism spectra with a large double signal; peaks at 696 nm (+) and 680 nm (?). In the circular dichroism spectra obtained with agranal chloroplasts of bundle sheath cells, this large double signal is absent. Separation of grana lamellae, in a medium of low salt concentration and in KSCN solution, resulted only in a slight decrease of the amplitude, while upon treatment with digitonin the large double signal disappeared. A negative signal of the chlorophyll b peak at 654 nm was observed in the case of both granal and agranal chloroplasts, and it was not affected either by low salt or by digitonin treatment. A positive peak at about 515 nm was higher in granal than in agranal chloroplasts. PMID:16658498

Faludi-Daniel, Agnes; Demeter, S.; Garay, A. S.

1973-01-01

96

Time-resolved demagnetization of Co2MnSi observed using x-ray magnetic circular dichroism and an ultrafast streak camera.  

PubMed

The demagnetization dynamics of the Heusler alloy Co(2)MnSi was studied using picosecond time-resolved x-ray magnetic circular dichroism. The sample was excited using femtosecond laser pulses. In contrast to the sub-picosecond demagnetization of the metal ferromagnet Ni, substantially slower demagnetization with a time constant of 3.5 ± 0.5 ps was measured. This could be explained by a spin-dependent band gap inhibiting the spin-flip scattering of hot electrons in Co(2)MnSi, which is predicted to be half-metallic. A universal demagnetization time constant was measured across a range of pump power levels. PMID:21389561

Opachich, Y P; Comin, A; Bartelt, A F; Young, A T; Scholl, A; Feng, J; Schmalhorst, J; Shin, H J; Engelhorn, K; Risbud, S H; Reiss, G; Padmore, H A

2010-04-21

97

Large Amplitude Dynamic Events Near the Mesopause Observed in Na Lidar Measured Wind, Temperature, and Density  

Microsoft Academic Search

Large amplitude dynamic events are frequently observed in the 85-105 km altitude region in data from Starfire, NM, Maui, HA, and Urbana, IL. Similar events at Maui have been analyzed by Larsen et al., [2004, J. Geophys. Res., 109, doi:10.1029\\/2002JF003067] and Hurd et al. [CEDAR poster, Utah, 2008] from Na lidar data. The events have a vertical extent of large

G. R. Swenson; A. Liu; C. Carlson; X. Lu; T. Mangognia; Z. Li

2008-01-01

98

Extreme Ultraviolet Explorer deep survey observations of a large flare on AU Microscopii  

NASA Technical Reports Server (NTRS)

We have made the first extended observation of a stellar flare in the EUV with 100 s time resolution. The flare was detected on AU Mic by the Extreme Ultraviolet Explorer satellite at 12:38 UT on 1992 July 15 during a 4 d observation from 1992 July 14 to 18. This was a large flare detected in the Lexan/boron (65-190 A) band with an observed peak count rate of 7.0 +/- 0.5 counts/s, corresponding to a peak luminosity of 10 exp 30 erg/s in the Lexan/boron bandpass. This is significantly above the measured quiescent level of 0.4 +/- 0.2 counts/s. The flare consisted of a sharp peak lasting about 2 hr, followed by a decaying tail that lasted more than a day. The total EUV energy of the event is estimated to be 3 x 10 exp 34 ergs. A second, smaller flare was also observed and is described. We conclude that the large emission measures on order of 6 x 10 exp 53/cu cm are due to large volumes with characteristic length scales of order the stellar radius. We compare these EUV observations with stellar flare observations in other bandpasses and estimate the likelihood of seeing similar flares in future observations.

Cully, Scott L.; Siegmund, Oswald H. W.; Vedder, Peter W.; Vallerga, John V.

1993-01-01

99

Large-eddy simulation of katabatic winds. Part 1: Comparison with observations  

Microsoft Academic Search

Steady-state quasi-one-dimensional large-eddy simulations of slope winds over simple terrain are presented. The model results\\u000a of up-slope flow are compared to previous simulations by Schumann (1990), and good agreement is found. Modelled downslope\\u000a winds are compared to meteorological observations from two glaciers. The vertical profiles of velocity and buoyancy agree\\u000a with the observations, whereas larger discrepancies are found between the

Simon L. Axelsen; Han van Dop

2009-01-01

100

Arrival time calculation for interplanetary coronal mass ejections with circular fronts and application to STEREO observations of the 2009 February 13 eruption  

E-print Network

A goal of the NASA STEREO mission is to study the feasibility of forecasting the direction, arrival time and internal structure of solar coronal mass ejections (CMEs) from a vantage point outside the Sun-Earth line. Through a case study, we discuss the arrival time calculation of interplanetary CMEs (ICMEs) in the ecliptic plane using data from STEREO/SECCHI at large elongations from the Sun in combination with different geometric assumptions about the ICME front shape (Fixed-\\Phi (FP): a point and harmonic Mean (HM): a circle). These forecasting techniques use single-spacecraft imaging data and are based on the assumptions of constant velocity and direction. We show that for the slow (350 km/s) ICME on 2009 February 13-18, observed at quadrature by the two STEREO spacecraft, the results for the arrival time given by the HM approximation are more accurate by 12 hours than those for FP in comparison to in situ observations of solar wind plasma and magnetic field parameters by STEREO/IMPACT/PLASTIC, and by 6 ho...

Möstl, C; Lugaz, N; Farrugia, C J; Davies, J A; Temmer, M; Veronig, A M; Harrison, R; Crothers, S; Luhmann, J G; Galvin, A B; Zhang, T L; Baumjohann, W; Biernat, H K

2011-01-01

101

Observations, Evaporation and Preliminary Modelling of Over-Lake Meteorology on Large African Lakes  

Microsoft Academic Search

Water quality models of lakes require accurate specification of the advective and turbulent transport fields. These are usually obtained from lake hydrodynamic models. In turn, hydrodynamic models require accurate specification of meteorological forcing. Uncertain specification of meteorological forcing over large lakes is one of the main reasons for the lack of correspondence between three-dimensional hydrodynamic models and observations of lake

P. F. HAMBLIN; P. Verburg; P. Roebber; H. A. Bootsma; R. E. Hecky

102

Large density fluctuations in the martian ionosphere as observed by the Mars Express radar sounder  

E-print Network

observed in the same region. The power spectrums of both the density and magnetic field fluctuations have as much as a factor of three or more at high altitudes. Large magnetic field fluctuations are also and magnetic field fluctuations in the martian ionosphere, mainly at high alti- tudes, above about 275 km

Gurnett, Donald A.

103

Earth Observations for rapid response to large earthquakes Supervisors: Dr Zhenhong Li and Prof Trevor Hoey  

E-print Network

Earth Observations for rapid response to large earthquakes Supervisors: Dr Zhenhong Li and Prof Trevor Hoey School of Geographical and Earth Sciences, University of Glasgow, UK Earthquakes, together societies. Independently of their societal impact, earthquakes are central to our basic understanding

Guo, Zaoyang

104

Earth Observations for rapid response to large earthquakes Supervisors: Dr Zhenhong Li (1)  

E-print Network

Earth Observations for rapid response to large earthquakes Supervisors: Dr Zhenhong Li (1) , Prof, UK (2) School of Earth and Environment, University of Leeds, UK Earthquakes, together with landslides of their societal impact, earthquakes are central to our basic understanding of the earth system

Glasgow, University of

105

Methods for Extremely Large Scale Media Experiments and Observational Studies Gary King, Benjamin Schneer & Ariel White  

E-print Network

) � The goal of media outlets (and our study) is activated opinion � Goal: influence "the conversation": people engaging with others, trying to influence politics � Social media is of direct interest, highlyMethods for Extremely Large Scale Media Experiments and Observational Studies Gary King, Benjamin

106

Approximating the Conditional Density Given Large Observed Values via a Multivariate Extremes Framework, with Application to  

E-print Network

Washington DC. We obtain a predictive distribution for the air pollutant at a location given the air the 0.97 quantile of the empirical distribution for its location. Certainly, air pollution levels Phenomena such as air pollution levels are of greatest interest when observations are large, but standard

Cooley, Dan

107

Observation and analysis of large-scale human Janez Pers a,,1,2  

E-print Network

of the observed athletes with reasonable amount of operator work. The system was developed using the recordings, the motion of a player running across the entire playing field). We describe an alternative approach obtain position data for all 14 handball players on a 40 Ã? 20 meter large court with RMS error better

Kovacic, Stanislav

108

Observations of TeV gamma rays from Markarian 501 at large zenith angles  

E-print Network

TeV gamma rays from the blazar Markarian 501 have been detected with the University of Durham Mark 6 atmospheric Cerenkov telescope using the imaging technique at large zenith angles. Observations were made at zenith angles in the range 70 - 73 deg during 1997 July and August when Markarian 501 was undergoing a prolonged and strong flare.

P M Chadwick; K Lyons; T J L McComb; K J Orford; J L Osborne; S M Rayner; S E Shaw; K E Turver

1999-04-29

109

Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO) V. Andersson  

E-print Network

Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO) V. Andersson , P. Chen, T. Kamae, G, Japan We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma of balloon experiments lasting 6-8 hours each. Compton scattering has highest potential for measuring low

Haviland, David

110

What if charged current events at large Q 2 are observed at HERA?  

Microsoft Academic Search

An excess of events at large Q2 with a positron in the final state has been observed at HERA which, if confirmed, could be a signal of new physics. It is not clear at present if a signal of comparable rate is also seen in the charged-current channel (with an antineutrino in the final state). In this note we analyse

Guido Altarelli; Gian Francesco Giudice; Michelangelo L Mangano

1997-01-01

111

Observations of short large-amplitude magnetic structures at a quasi-parallel shock  

Microsoft Academic Search

The authors have conducted a detailed analysis of a set of events termed short large-amplitude magnetic structures (SLAMS) observed at an encounter of the quasi-parallel bow shock by the AMPTE UKS and IRM satellites. They have identified isolated SLAMS, surrounded by solar wind conditions, and embedded SLAMS, which lie within or form the boundary with regions of significant heating and

Steven J. Schwartz; David Burgess; William P. Wilkinson; Ramona L. Kessel; Malcolm Dunlop; H. Luehr

1992-01-01

112

Wideband Very Large Array Observations of A2256. I. Continuum, Rotation Measure, and Spectral Imaging  

NASA Astrophysics Data System (ADS)

We report new observations of A2256 with the Karl G. Jansky Very Large Array (VLA) at frequencies between 1 and 8 GHz. These observations take advantage of the 2:1 bandwidths available during a single observation to study the spectral index, polarization, and rotation measure as well as using the associated higher sensitivity per unit time to image total intensity features down to ~0.''5 resolution. We find that the Large Relic, which dominates the cluster, is made up of a complex of filaments that show correlated distributions in intensity, spectral index, and fractional polarization. The rotation measure varies across the face of the Large Relic but is not well correlated with the other properties of the source. The shape of individual filaments suggests that the Large Relic is at least 25 kpc thick. We detect a low surface brightness arc connecting the Large Relic to the Halo and other radio structures, suggesting a physical connection between these features. The center of the F-complex is dominated by a very steep-spectrum, polarized, ring-like structure, F2, without an obvious optical identification, but the entire F-complex does have interesting morphological similarities to the radio structure of NGC 1265. Source C, the Long Tail, is unresolved in width near the galaxy core and is <~ 100 pc in diameter there. This morphology suggests either that C is a one-sided jet or that the bending of the tails takes place very near the core, consistent with the parent galaxy having undergone extreme stripping. Overall it seems that many of the unusual phenomena can be understood in the context of A2256 being near the pericenter of a slightly off-axis merger between a cluster and a smaller group. Given the lack of evidence for a strong shock associated with the Large Relic, other models should be considered, such as reconnection between two large-scale magnetic domains.

Owen, Frazer N.; Rudnick, Lawrence; Eilek, Jean; Rau, Urvashi; Bhatnagar, Sanjay; Kogan, Leonid

2014-10-01

113

On the observation of Cerenkov images at large core distances in the EAS of ultrahigh energies  

NASA Astrophysics Data System (ADS)

A slit camera is suggested for observation of EAS images at large core distances R. Being incorporated in the network of EAS particle detectors with large separation between them (0954-3899/23/2/011/img5 km) the imaging cameras make possible the measurement of the angular distribution of light responsible for the image. Experimental angular light distribution helps to decode the EAS cascade curve from the image data. Analysis of the image data expected at large core distances shows that the early stage of the EAS development (depths in atmosphere 0954-3899/23/2/011/img6) could be studied. For this application the traditional Cerenkov detector data, the radiation lateral distribution and the pulse shape at large core distances are uncertain without knowledge of angular light distribution. The advantage of the slit camera array is also in its suppression of the direct moon light that makes the duty cycle of the Cerenkov array longer.

Garipov, G. K.; Khrenov, B. A.

1997-02-01

114

Elastic spin observables and proton wave function normalization at large t  

SciTech Connect

We summarize the role of spin observables in testing the foundations of exclusive QCD at large t. Polarized elastic scattering experiments can shed light on fundamental properties of protons, such as helicity conservation, normalization of the wave function and structure. Specific QCD motivated predictions for the spin observables are presented, which can be tested at polarized proton beam facilities. In this paper, two kinematic regions are considered: 90{degrees} c.m. at large {vert_bar} t {vert_bar} and the intermediate hard scattering regime: m{sub p}{sup 2} {much_lt}{vert_bar} t {vert_bar}{much_lt} s. Theoretical models, which predict the spin observables in these regions, are reviewed. These are compared with present elastic pp data and a program is suggested for future elastic polarized pp scattering experiments, which can be used to further our knowledge of proton structure.

Ramsey, G.P. [Loyola Univ., Chicago, IL (United States). Dept. of Physics]|[Argonne National Lab., IL (United States)

1993-11-29

115

The x ray properties of a large, uniform QSO sample: Einstein observations of the LBQS  

NASA Technical Reports Server (NTRS)

Although there are large numbers of Quasi Stellar Objects (QSO's) now observed in X rays, extensive X-ray observations of uniformly selected, 'complete' QSO samples are more rare. The Large Bright QSO Survey (LBQS) consists of about 1000 objects with well understood properties, most brighter than B = 18.8 and thus amenable to X-ray detections in relatively brief exposures. The sample is thought to be highly complete in the range 0.2 less than z less than 3.3, a significantly broader interval than many other surveys. The Einstein IPC observed 150 of these objects, mostly serendipitously, during its lifetime. We report the results of an analysis of these IPC data, considering not only the 20 percent of the objects we find to have positive X-ray detections, but also the ensemble X-ray properties derived by 'image stacking'.

Margon, B.; Anderson, S. F.; Xu, X.; Green, P. J.; Foltz, C. B.

1992-01-01

116

A bifunctional amorphous polymer exhibiting equal linear and circular photoinduced birefringences.  

PubMed

The large and reversible photoinduced linear and circular birefringences in azo-compounds are at the basis of the interest in these materials, which are potentially useful for several applications. Since the onset of the linear and circular anisotropies relies on orientational processes, which typically occur on the molecular and supramolecular length scale, respectively, a circular birefringence at least one order of magnitude lower than the linear one is usually observed. Here, the synthesis and characterization of an amorphous polymer with a dimeric repeating unit containing a cyanoazobenzene and a cyanobiphenyl moiety are reported, in which identical optical linear and circular birefringences are induced for proper light dose and ellipticity. A pump-probe technique and an analytical method based on the Stokes-Mueller formalism are used to investigate the photoinduced effects and to evaluate the anisotropies. The peculiar photoresponse of the polymer makes it a good candidate for applications in smart functional devices. PMID:25257542

Royes, Jorge; Provenzano, Clementina; Pagliusi, Pasquale; Tejedor, Rosa M; Piñol, Milagros; Oriol, Luis

2014-11-01

117

Scintillation-Induced Circular Polarization in Pulsars and Quasars  

E-print Network

We present a physical interpretation for the generation of circular polarization resulting from the propagation of radiation through a magnetized plasma in terms of a rotation measure gradient, or `Faraday wedges'. Criteria for the observability of scintillation-induced circular polarization are identified. Application of the theory to the circular polarization in pulsars and compact extragalactic sources is discussed.

J. -P. Macquart; D. B. Melrose

2000-07-28

118

ARRIVAL TIME CALCULATION FOR INTERPLANETARY CORONAL MASS EJECTIONS WITH CIRCULAR FRONTS AND APPLICATION TO STEREO OBSERVATIONS OF THE 2009 FEBRUARY 13 ERUPTION  

SciTech Connect

One of the goals of the NASA Solar TErestrial RElations Observatory (STEREO) mission is to study the feasibility of forecasting the direction, arrival time, and internal structure of solar coronal mass ejections (CMEs) from a vantage point outside the Sun-Earth line. Through a case study, we discuss the arrival time calculation of interplanetary CMEs (ICMEs) in the ecliptic plane using data from STEREO/SECCHI at large elongations from the Sun in combination with different geometric assumptions about the ICME front shape [fixed-{Phi} (FP): a point and harmonic mean (HM): a circle]. These forecasting techniques use single-spacecraft imaging data and are based on the assumption of constant velocity and direction. We show that for the slow (350 km s{sup -1}) ICME on 2009 February 13-18, observed at quadrature by the two STEREO spacecraft, the results for the arrival time given by the HM approximation are more accurate by 12 hr than those for FP in comparison to in situ observations of solar wind plasma and magnetic field parameters by STEREO/IMPACT/PLASTIC, and by 6 hr for the arrival time at Venus Express (MAG). We propose that the improvement is directly related to the ICME front shape being more accurately described by HM for an ICME with a low inclination of its symmetry axis to the ecliptic. In this case, the ICME has to be tracked to >30{sup 0} elongation to obtain arrival time errors < {+-} 5 hr. A newly derived formula for calculating arrival times with the HM method is also useful for a triangulation technique assuming the same geometry.

Moestl, C.; Rollett, T.; Temmer, M.; Veronig, A. M.; Biernat, H. K. [Institute of Physics, University of Graz, Graz A-8010 (Austria); Lugaz, N. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Farrugia, C. J.; Galvin, A. B. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Davies, J. A.; Harrison, R. A.; Crothers, S. [RAL Space, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Luhmann, J. G. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Zhang, T. L.; Baumjohann, W., E-mail: christian.moestl@uni-graz.at [Space Research Institute, Austrian Academy of Sciences, Graz A-8042 (Austria)

2011-11-01

119

Explorer 45 wave observations during the large magnetic storm of August 4-5, 1972  

NASA Technical Reports Server (NTRS)

The magnetospheric compression associated with the very large magnetic storm of August 4-5, 1972, provided an opportunity for Explorer 45 to observe plasma waves in the magnetosphere and the magnetosheath during extremely disturbed conditions. Electrostatic noise bursts were observed near the plasmapause in electric-field channels from 35 Hz to 5.62 kHz. In the outer magnetosphere, electric-field noise bands apparently harmonically related to the electron gyrofrequency with components as low as 3 kHz and as high as 50 kHz were observed. The electric field of the fundamental was perpendicular to the magnetic-field vector. A mechanism including the electron cyclotron instability may generate the noise band. Hiss of 100-1000 Hz was observed in the outer magnetosphere. The electromagnetic hiss was generally weak and was observed in the magnetic wide-band data only when it was strong. In the magnetosheath broad band, incoherent noise (hiss) was observed from 1 Hz to 100 kHz. This magnetosheath hiss was the strongest phenomenon observed by the plasma-wave detectors during the lifetime of Explorer 45. The highest intensities of magnetosheath hiss occurred at the magnetopause. Its broad-band nature suggests that magnetosheath hiss was generated locally. Broad-band noise bursts and short bursts of chorus were also observed in the magnetosheath.

Taylor, W. W. L.; Anderson, R. G.

1977-01-01

120

Laboratory Observation of Large-Amplitude Electrostatic Fluctuations Driven by Magnetic Reconnection  

NASA Astrophysics Data System (ADS)

We report recent observations of nonlinear electrostatic fluctuations excited during spontaneous reconnection events on the VTF experiment~[1]. Electrostatic fluctuations are observed by small, high-bandwidth, impedance- matched Langmuir probes. Among a large number of wave phenomena, we observe narrow, large-amplitude, positive potential spikes, with fluctuations in probe current on the order of the ion saturation current drawn by the probe, implying ñ/n ~ 1, or e\\tilde{?} / k Te ~ 1. The spikes are observed in conjunction with large inductive electric fields (the "reconnection electric field"). With arrays of such probes we have observed the speed and shape of these propagating structures. The spike drift speed, which is parallel to the electron drift, is roughly 5 106~m/s, or 2vte (vte = \\sqrt{2kTe/me}). Based on the drift speed and the time to cross a single probe tip, we infer that the parallel size is 1-2~mm (50-100~?D, or 5-10~?e). Observations with probes spaced perpendicular to the magnetic field shows that the perpendicular size is also 1-2~mm. Finally, we will discuss our interpretation of the structures and their generation mechanism, with insights from a newly installed electron energy analyzer. [1] J. Egedal, W. Fox, N. Katz, M. Porkolab, K. Reim, and E. Zhang. (2007). PRL 98, 015003. This was supported by DOE contracts DE-FC02-04ER54786 and DE-FG02-06ER54878, and NSF/DOE PHY-0613734

Fox, W.; Porkolab, M.; Egedal, J.; Katz, N.

2007-12-01

121

Observations of large-amplitude, narrowband whistlers at stream interaction regions  

NASA Astrophysics Data System (ADS)

We present the first solar wind observations of large-amplitude, narrowband waveforms in the frequency range 10-100 Hz, consistent with the whistler mode. These whistlers are only observable in high time resolution electric field waveform data provided by the Time Domain Sampler (TDS) instrument on STEREO. Amplitudes range from a few to >40 mV/m peak-to-peak, one to three orders of magnitude larger than any previous observations of whistler mode waves in the solar wind. The whistlers are obliquely propagating with a large electrostatic component and are right-hand elliptically polarized in the spacecraft frame. The whistlers occur in groups that are strongly correlated with stream interaction regions (SIRs). The groups persist from a few seconds to minutes and are observed at 88% of SIRs and 17% of shocks from available data. A more detailed look shows that the whistler groups are observed near sudden disturbances of the solar wind magnetic field and plasma. We suggest that, owing to the oblique and narrowband nature of these waves, an electron or ion beam instability may be responsible for their creation. Test particle simulations show that the waves can interact strongly with halo (>60 eV) electrons. Test electrons were scattered by tens of degrees and energized/deenergized by up to 50% in a few tens of milliseconds. Thus these whistlers may play an important role in the dynamics of solar wind electrons within SIRs and near some shocks.

Breneman, A.; Cattell, C.; Schreiner, S.; Kersten, K.; Wilson, L. B., III; Kellogg, P.; Goetz, K.; Jian, L. K.

2010-08-01

122

ISIS observations of auroral particles and large-scale Birkeland currents  

NASA Technical Reports Server (NTRS)

Simultaneous electron and positive ion observations made with single-component magnetic perturbations on the ISIS-2 satellite are used to compare and contrast the relationships between primary and secondary auroral particle distributions at 5 eV-15 keV, and the large-scale Birkeland currents, in the pre- and post-midnight local time sectors. No unique relation is found between the regions of the Birkeland current system and regions of auroral particle distribution, though repeatable systematics in the region of upward-directed current are observed, and little evidence exists in either local time sector for the direct detection of the downward current-associated current carriers.

Klumpar, D. M.

1981-01-01

123

Circular motion Isaac Newtona)  

E-print Network

deduce Kepler's laws from their result, Newton could and did. Halley and Wren, properly recognizingCircular motion Isaac Newtona) and Richard Conn Henryb) Received 20 October 1999; accepted 30 that occurs in uniform circular motion is presented, and is advocated for use in high school and college

124

Physclips: Circular Motion  

NSDL National Science Digital Library

This web page provides a multimedia introduction to circular motion. It includes topics such as acceleration, velocity, vectors, the Earth's rotation, and nonuniform circular motion. Short video clips and diagrams are integrated with text to promote understanding of important concepts. This tutorial is part of the PhysClip collection of web-based resources on introductory mechanics, electricity, and magnetism.

Wolfe, Joe

2009-10-14

125

Observation of large diamagnetism in La-Sr-Nb-O films up to room temperature  

SciTech Connect

Large diamagnetic transitions along with sharp resistive transitions were observed in the La-Sr-Nb-O system near room temperature (approx. 290 K). The amplitude of the diamagnetism reaches 35% of that of a pure Nb sheet. In addition, a behavior similar to weak magnetic spin ordering was observed for some samples at a temperature of about 290 K, over a temperature range of 30 K. The diamagnetism reappears above this temperature and continues up to T approx. 320 K. It is not clear what composition ratio of La-Sr-Nb-O is responsible for this large diamagnetism and the high critical temperature. The yield probability of these samples is around 50%. The characteristics of the samples having not passed through many thermal cycles remain stable for about 1 month.

Ogushi, T.; Higo, S.; Suresha, N.G.; Honjo, Y.; Ozono, Y.; Kawano, I.; Hakuraku, Y.; Rinderer, L.

1988-11-01

126

Observations of the earth's polar cleft at large radial distances with the Hawkeye 1 magnetometer  

NASA Technical Reports Server (NTRS)

Based on 364 spacecraft passes through the dayside region, the position of the polar cleft at large radial distances was determined with the magnetometer flown on Hawkeye 1. This data set is ideal for the study of the cusp and cleft region. Identification of the cleft depended on noting strong negative deviations of the magnetic field strength in the region from that of the dipole field. In solar magnetic coordinates, cleft observations were found between 40 deg and 70 deg latitude and + or - 75 deg latitude and + or - 75 deg longitude, while in geocentricmagnetospheric coordinates, these observations were found between 20 deg and 75 deg latitude and + or - 75 deg longitude. The extreme longitudinal extent of 150 deg is larger than those reported in some previous studies. Large magnetic depressions associated with the cleft extend out to 12 earth radii.

Farrell, W. M.; Van Allen, J. A.

1990-01-01

127

Orbital Circularization of a Planet Accreting Disk Gas: The Formation of Distant Jupiters in Circular Orbits Based on a Core Accretion Model  

NASA Astrophysics Data System (ADS)

Recently, gas giant planets in nearly circular orbits with large semimajor axes (a ~ 30-1000 AU) have been detected by direct imaging. We have investigated orbital evolution in a formation scenario for such planets, based on a core accretion model. (1) Icy cores accrete from planetesimals at <~ 30 AU, (2) they are scattered outward by an emerging nearby gas giant to acquire highly eccentric orbits, and (3) their orbits are circularized through the accretion of disk gas in outer regions, where they spend most of their time. We analytically derived equations to describe the orbital circularization through gas accretion. Numerical integrations of these equations show that the eccentricity decreases by a factor of more than 5 while the planetary mass increases by a factor of 10. Because runaway gas accretion increases planetary mass by ~10-300, the orbits are sufficiently circularized. On the other hand, a is reduced at most only by a factor of two, leaving the planets in the outer regions. If the relative velocity damping by shock is considered, the circularization slows down, but is still efficient enough. Therefore, this scenario potentially accounts for the formation of observed distant jupiters in nearly circular orbits. If the apocenter distances of the scattered cores are larger than the disk sizes, their a shrink to a quarter of the disk sizes; the a-distribution of distant giants could reflect the outer edges of the disks in a similar way that those of hot jupiters may reflect inner edges.

Kikuchi, Akihiro; Higuchi, Arika; Ida, Shigeru

2014-12-01

128

Large-Scale Atmospheric Pollution Over Eastern China: Results From Ozone and Carbon Monoxide Observation  

NASA Astrophysics Data System (ADS)

Global CTM studies, satellite data analysis, and air pollution statistics have verified the large-scale atmospheric pollution over East Asia. Long-range transport studies of these air pollutants indicate that theirs effect could be observed even in the intercontinental or hemispherical scale. According to the models results and satellite data, the largest anthropogenic emission region is found over the mid-latitude eastern China. In this work, we investigated the present situation of large-scale atmospheric ozone and carbon monoxide pollution over eastern China. Since 2003, three regional ozone and carbon monoxide monitoring sites have been established at Mt. Tai (36 15N, 117 07E, 1524 m above sea level) in Shandon Province, Mt. Huang (30 10N, 118 11E, 1841 m asl) in Anhui Province, and Mt. Hua (34 20N, 110 05E, 2065 m asl) in Shaanxi Province. The results from observation show high mixing ratios and large variations of ozone and carbon monoxide, especially during spring and early-summer, at every observatory. Seasonal cycles of ozone and CO at these sites could be partly explained by the air mass climatology but the enhancements by regional anthropogenic emission are found to be dominant throughout the year. The large episodic ozone pollution events have been observed in early-summer for three consecutive years. Comparison of ozone and carbon monoxide in eastern China with the data from remote mid-latitude Northern Hemisphere background site in eastern Siberia show clearly different characteristics attributed to the regional sources. In this presentation, the sources and distribution of ozone and carbon monoxide in eastern China, theirs controlling factors, and their potential impact to environment will be discussed based mainly on observational results.

Pochanart, P.; Akimoto, H.; Li, J.; Wang, Z.

2005-12-01

129

The Large-Scale Cosmic-Ray Anisotropy as Observed with Milagro  

Microsoft Academic Search

Results are presented of a harmonic analysis of the large-scale cosmic-ray (CR) anisotropy as observed by the Milagro observatory. We show a two-dimensional display of the sidereal anisotropy projections in right ascension (R.A.) generated by the fitting of three harmonics to 18 separate declination bands. The Milagro observatory is a water Cherenkov detector located in the Jemez mountains near Los

A. A. Abdo; B. T. Allen; T. Aune; D. Berley; S. Casanova; C. Chen; B. L. Dingus; R. W. Ellsworth; L. Fleysher; R. Fleysher; M. M. Gonzalez; J. A. Goodman; C. M. Hoffman; B. Hopper; P. H. Hüntemeyer; B. E. Kolterman; C. P. Lansdell; J. T. Linnemann; J. E. McEnery; A. I. Mincer; P. Nemethy; D. Noyes; J. Pretz; J. M. Ryan; P. M. Saz Parkinson; A. Shoup; G. Sinnis; A. J. Smith; G. W. Sullivan; V. Vasileiou; G. P. Walker; D. A. Williams; G. B. Yodh

2009-01-01

130

Observations of dwarf planet (136199) Eris and other large TNOs on Lulin Observatory  

Microsoft Academic Search

To provide comprehensive observations and in-depth standy of the physical property of the trans-neptunian objects (TNOs), the Lulin Observatory in Taiwan has started a program to study the time variabilities of lightcurves of large TNOs and dwarf planets. Our initial results show that (50000) Quaoar has a significant brightness variation of ?m?0.3 with a rotation period of about 18.84h while

H.-W. Lin; Y.-L. Wu; W.-H. Ip

2007-01-01

131

Observations of dwarf planet (136199) Eris and other large TNOs on Lulin Observatory  

Microsoft Academic Search

To provide comprehensive observations and in-depth standy of the physical property of the trans-neptunian objects (TNOs), the Lulin Observatory in Taiwan has started a program to study the time variabilities of lightcurves of large TNOs and dwarf planets. Our initial results show that (50000) Quaoar has a significant brightness variation of Deltam ˜ 0.3 with a rotation period of about

H.-W. Lin; Y.-L. Wu; W.-H. Ip

2007-01-01

132

Radiometer requirements for Earth-observation systems using large space antennas  

NASA Technical Reports Server (NTRS)

Requirements are defined for Earth observation microwave radiometry for the decade of the 1990's by using large space antenna (LSA) systems with apertures in the range from 50 to 200 m. General Earth observation needs, specific measurement requirements, orbit mission guidelines and constraints, and general radiometer requirements are defined. General Earth observation needs are derived from NASA's basic space science program. Specific measurands include soil moisture, sea surface temperature, salinity, water roughness, ice boundaries, and water pollutants. Measurements are required with spatial resolution from 10 to 1 km and with temporal resolution from 3 days to 1 day. The primary orbit altitude and inclination ranges are 450 to 2200 km and 60 to 98 deg, respectively. Contiguous large scale coverage of several land and ocean areas over the globe dictates large (several hundred kilometers) swaths. Radiometer measurements are made in the bandwidth range from 1 to 37 GHz, preferably with dual polarization radiometers with a minimum of 90 percent beam efficiency. Reflector surface, root mean square deviation tolerances are in the wavelength range from 1/30 to 1/100.

Keafer, L. S., Jr.; Harrington, R. F.

1983-01-01

133

Survey of the ionospheric disturbances related with large seismic events in multi-satellite ionospheric observations  

NASA Astrophysics Data System (ADS)

We survey the ionospheric disturbances in the plasma and electro-magnetic wave measurements during the simultaneous observation period of DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions), CHAMP (CHAllenging Minisatellite Payload) and DMSP(Defense Meteorological Satellite Program) missions. The multi-satellite observation around three large earthquakes that occurred between 2004 and 2005 were investigated. The observational evidences of the earth-quake precursory phenomena and the recent progress of physical modeling of the ionospheric disturbances caused by the coupling of the stressed rock, Earth surface charges, atmosphere, and ionosphere system are reviewed. Then, we focus on identifying the precursory disturbances from the well-studied plasma disturbances in the ionosphere, which are known to originate from various physical mechanism other than the seismic activities. Electron density/temperature, ion density/temperature, and electro-magnetic field/wave data measured by various instruments equipped in the satellites were analyzed in finding specific examples of anomaly caused by large seismic activities. Finally, the possibility of forecasting or predicting large earthquakes using the plasma measurements of LEO (low earth orbit) satellites will be discussed.

Ryu, K.; Chae, J.; Lee, E.; Kil, H.

2013-12-01

134

Considerations for observational research using large data sets in radiation oncology.  

PubMed

The radiation oncology community has witnessed growing interest in observational research conducted using large-scale data sources such as registries and claims-based data sets. With the growing emphasis on observational analyses in health care, the radiation oncology community must possess a sophisticated understanding of the methodological considerations of such studies in order to evaluate evidence appropriately to guide practice and policy. Because observational research has unique features that distinguish it from clinical trials and other forms of traditional radiation oncology research, the International Journal of Radiation Oncology, Biology, Physics assembled a panel of experts in health services research to provide a concise and well-referenced review, intended to be informative for the lay reader, as well as for scholars who wish to embark on such research without prior experience. This review begins by discussing the types of research questions relevant to radiation oncology that large-scale databases may help illuminate. It then describes major potential data sources for such endeavors, including information regarding access and insights regarding the strengths and limitations of each. Finally, it provides guidance regarding the analytical challenges that observational studies must confront, along with discussion of the techniques that have been developed to help minimize the impact of certain common analytical issues in observational analysis. Features characterizing a well-designed observational study include clearly defined research questions, careful selection of an appropriate data source, consultation with investigators with relevant methodological expertise, inclusion of sensitivity analyses, caution not to overinterpret small but significant differences, and recognition of limitations when trying to evaluate causality. This review concludes that carefully designed and executed studies using observational data that possess these qualities hold substantial promise for advancing our understanding of many unanswered questions of importance to the field of radiation oncology. PMID:25195986

Jagsi, Reshma; Bekelman, Justin E; Chen, Aileen; Chen, Ronald C; Hoffman, Karen; Shih, Ya-Chen Tina; Smith, Benjamin D; Yu, James B

2014-09-01

135

Bridging the Gap between Large-Scale Simulations and Observations of Star Forming Cores  

NASA Astrophysics Data System (ADS)

Numerical simulations and observations of star forming cores are topics that both see a lot of progress these years. MHD simulations of molecular clouds have reached a level, where it is possible to evolve the cloud on parsec scale, while simultaneously resolving the neighbourhood around the individual protostars on AU scale. At the same time interferometers such as ALMA, with its increased sensitivity and resolving capabilities, are making it possible to zoom in on the protostellar cores in their earliest stages and map their gas and dust content. The advances in simulations and observations also open the possibility of comparing the two directly. I will present synthetic observations of a large number of protostellar cores, created from the high resolution numerical simulations of Haugbølle, Padoan and Nordlund in prep (see Padoan et al 2012 for similar lower resolution models). The synthetic observations are compared directly to real observations obtained from a range of different submm telescopes. The motivation for comparing real and synthetic observations is twofold. It enables us to test the validity of the simulations by ensuring that the synthetic observations agree with the real ones, and in the cases where they differ to identify the issues. In addition to this, through the simulations we are able to gain additional insight into the physics behind the observations. I will present several cases where synthetic and real observations have been compared. In one example of this we used 24 ?m Spitzer maps, and 850 ?m SCUBA maps from Perseus and Ophiuchus to calculate the distribution of distances between protostars and their parental cores (Jørgensen et. al. 2007, 2008). Both real and synthetic observations produce a centrally peaked distribution (HWHM smaller than the typical core radius). This indicates that on average newly formed protostars do not migrate far away from their parental core.

Frimann, Søren; Jørgensen, Jes Kristian

2014-07-01

136

Observations of CO2 and CH4 enhancements over large point sources using GOSAT  

NASA Astrophysics Data System (ADS)

We present the first results of the effort to directly monitor GHG emissions from intense sources such as large power plants and populated cities (large point sources, LPS) using Greenhouse gas Observing SATellite (GOSAT). National GHG emissions are calculated according to the local activity statistics by sector and their inventories are compiled and reported on annual basis by country. Such inventories are presently the only measure of national emissions, although these might not accurate due to statistical data quality and calculation methods. Towards monitoring of emission reductions an independent method to monitor emissions and verify emission inventories is required. Since August 2009 till December 2009, we have requested targeted mode measurements every 6 days over more than 300 LPS observation sites worldwide. The number is limited by GOSAT targeted mode observation allocation to one research project. Observation points include large power plants selected from CARMA (Carbon Monitoring and Action) global power plant database by emission intensity, and cities selected by population ranking. During 5 months, 154 XCO2 measurements over 74 LPS sites and 170 XCH4 measurements over 80 LPS sites were successfully retrieved. The observed concentrations at LPS sites were compared to zonal mean concentrations and local background values, which were calculated using GOSAT observational data. We also perfomed point-wise model simulations for XCO2 using high resolution (1 km x 1 km) emission dataset and an Eulerian-Lagrangian coupled atmospheric transport model. The majority of the observation over LPS were higher than zonal mean concentrations, and also higher than background values on average. The average CO2 and CH4 enhancements for whole period were +0.51 ± 0.30 ppm (std. 3.51) for CO2 and +2.65 ± 0.78 ppb (std.15.8) for CH4. We can expect lower errors with the use of later versions of the retrieval (The versions of GOSAT L2 product use in this study are V00.03 and V00.10). The observed CO2 enhancement appeared to be close to model simulations (+0.78 ppm ± 0.10 ppm, std. 1.23), suggesting the observation data are in realistic range and there is only minor contamination by aerosols and clouds. Better results were obtained for countries with large percentage of the clear sky observations like Mexico and South Africa, where we observe good correlation between the model predictions and observations for CO2 on country average level. The level of uncertainty at this point (61% for CO2 and 29% for CH4 of the mean value) is still close to the level of the value itself, however a simple estimate suggests that it could be reduced to about 12% for CO2 and 5.9% for CH4 for whole 5-year operation of GOSAT with reasonably improved retrieval. These results demonstrate feasibility of observing man-made CO2 and CH4 emissions from space, which is being actively discussed in context of the planned satellite mission such as OCO-II and CarbonSat.

Oda, T.; Maksyutov, S.; Saito, M.; Valsala, V.; Ganshin, A.; Andres, R. J.; Yoshida, Y.; Yokota, T.

2010-12-01

137

Very Large Array and Jansky Very Large Array Observations of the Compact Radio Sources in M8  

NASA Astrophysics Data System (ADS)

We analyze high-resolution Very Large Array continuum observations of the M8 region carried out at several epochs that span a period of 30 yr. Our maps reveal two compact sources. One is associated with Her 36 SE, a possible companion of the O7 luminous massive star Her 36, and the other is associated with G5.97–1.17, whose proplyd nature was previously established. Using the analyzed data, we do not find significant time variability in any of these sources. The derived spectral index of >=0.1 for Her 36 SE, the marginal offset of the radio emission with the previous infrared detection, and the associated X-ray emission previously reported suggest the presence of an unresolved interaction region between the strong winds of Her 36 and Her 36 SE. This region would contribute non-thermal contamination to the global wind emission of Her 36, flattening its spectral index. On the other hand, the emission of G5.97–1.17 can also be explained by a mixture of thermal and non-thermal emission components, with different relative contributions of both emission mechanisms along the proplyd. We argue that the shock created by the photo-evaporation flow of the proplyd with the collimated stellar wind of Her 36 accelerates charged particles in G5.97–1.17, producing considerable synchrotron emission. On the contrary, an electron density enhancement at the southwest of G5.97–1.17 makes the thermal emission dominant over this region.

Masqué, Josep M.; Dzib, Sergio; Rodríguez, Luis F.

2014-12-01

138

Simultaneous Solar Maximum Mission (SMM) and Very Large Array (VLA) observations of solar active regions  

NASA Technical Reports Server (NTRS)

Very Large Array observations at 20 cm wavelength can detect the hot coronal plasma previously observed at soft x ray wavelengths. Thermal cyclotron line emission was detected at the apex of coronal loops where the magnetic field strength is relatively constant. Detailed comparison of simultaneous Solar Maximum Mission (SMM) Satellite and VLA data indicate that physical parameters such as electron temperature, electron density, and magnetic field strength can be obtained, but that some coronal loops remain invisible in either spectral domain. The unprecedent spatial resolution of the VLA at 20 cm wavelength showed that the precursor, impulsive, and post-flare components of solar bursts originate in nearby, but separate loops or systems of loops.. In some cases preburst heating and magnetic changes are observed from loops tens of minutes prior to the impulsive phase. Comparisons with soft x ray images and spectra and with hard x ray data specify the magnetic field strength and emission mechanism of flaring coronal loops. At the longer 91 cm wavelength, the VLA detected extensive emission interpreted as a hot 10(exp 5) K interface between cool, dense H alpha filaments and the surrounding hotter, rarefield corona. Observations at 91 cm also provide evidence for time-correlated bursts in active regions on opposite sides of the solar equator; they are attributed to flare triggering by relativistic particles that move along large-scale, otherwise-invisible, magnetic conduits that link active regions in opposite hemispheres of the Sun.

Willson, Robert F.

1991-01-01

139

Observation of the Crab Pulsar and Nebula with the Fermi Large Area Telescope  

SciTech Connect

The Crab Pulsar and Nebula are the remnants of the explosion of the supernova SN1054, which was observed by Chinese astronomers. Previously detected by EGRET, the Crab Pulsar and Nebula have been extensively observed in the gamma-ray energy band by the Large Area Telescope (LAT) onboard the Fermi satellite. The data collected by the LAT during its early operation stage have allowed a detailed measurement of the fluxes and of the energy spectra of both sources. The pulsar spectrum is consistent with the EGRET measurement in the region below 1 GeV and is well described by a power law with exponential cutoff at a few GeV. The nebula spectrum is well modeled by a sum of two power laws, identified respectively as the falling edge of the synchrotron and the rising edge of the inverse Compton components, and is in agreement with the observations from Earth-based telescopes.

Grondin, M.-H.; Lemoine-Goumard, M. [Universite de Bordeaux and CNRS/IN2P3, Centre d'Etudes Nucleaires Bordeaux Gradignan, UMR 5797, Gradignan, 33175 (France); Loparco, F. [Dipartimento di Fisica dell'Universita e del Politecnico di Bari, Via Amendola 173, I-70126, Bari (Italy); Istituto Nazionale di Fisica Nucleare Sezione di Bari, Via Orabona 4, I-70126, Bari (Italy); Mazziotta, M. N. [Istituto Nazionale di Fisica Nucleare Sezione di Bari, Via Orabona 4, I-70126, Bari (Italy)

2010-03-26

140

Estimating the impact of SWOT observations on the predictability of large-scale hydraulic models  

NASA Astrophysics Data System (ADS)

The proposed NASA/CNES Surface Water Ocean Topography (SWOT) satellite mission would provide unprecedented measurements of hydraulic variables globally. This paper investigates the impact of different SWOT-like observations on the capability to model and predict hydrodynamics over large scales. In order to achieve this, the Ensemble Sensitivity (ET) method was adopted, examining the cost functional between two 'models' run on a 40,000 km2 area of the Ohio basin. The ET method is similar to the adjoint method but uses an ensemble of model perturbations to calculate the sensitivity to observations. The experiment consists of two configurations of the LISFLOOD-FP hydraulic model. The first (baseline) simulation represents a calibrated 'best effort' model based on a sub-grid channel structure using observations for parameters and boundary conditions, whereas the second (background) simulation consists of estimated parameters and SRTM-based boundary conditions. Using accurate SWOT-like observations such as water level, water surface width and slope in an Ensemble Sensitivity framework allowed us to assess the true impact of SWOT observables over different temporal and spatial scales on our current capabilities to model and predict hydrodynamic characteristics at a potentially global scale. Estimating the model sensitivity to observations could also allow the identification of errors in the model structure and parameterizations, as well as facilitate the derivation of a SWOT data product with optimal characteristics (e.g. reach-averaging).

Schumann, G. J.; Andreadis, K.

2012-12-01

141

Rater Calibration when Observational Assessment Occurs at Large Scale: Degree of Calibration and Characteristics of Raters Associated with Calibration  

ERIC Educational Resources Information Center

Observational assessment is used to study program and teacher effectiveness across large numbers of classrooms, but training a workforce of raters that can assign reliable scores when observations are used in large-scale contexts can be challenging and expensive. Limited data are available to speak to the feasibility of training large numbers of…

Cash, Anne H.; Hamre, Bridget K.; Pianta, Robert C.; Myers, Sonya S.

2012-01-01

142

Generation of circular polarization of the CMB  

SciTech Connect

According to the standard cosmology, near the last scattering surface, the photons scattered via Compton scattering are just linearly polarized and then the primordial circular polarization of the cosmic microwave background (CMB) photons is zero. In this work we show that CMB polarization acquires a small degree of circular polarization when a background magnetic field is considered or the quantum electrodynamic sector of standard model is extended by Lorentz-noninvariant operators as well as noncommutativity. The existence of circular polarization for the CMB radiation may be verified during future observation programs, and it represents a possible new channel for investigating new physics effects.

Zarei, M.; Bavarsad, E.; Haghighat, M.; Mohammadi, R.; Motie, I.; Rezaei, Z. [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2010-04-15

143

EXPANDED VERY LARGE ARRAY CONTINUUM OBSERVATIONS TOWARD HOT MOLECULAR CORE CANDIDATES  

SciTech Connect

We have used the Expanded Very Large Array (EVLA) with two 1 GHz wide bands to obtain K-band (1.3 cm) continuum observations toward the following five hot molecular core candidates: IRAS 18151 - 1208, IRAS 18182 - 1433, IRAS 18345 - 0641, IRAS 18470 - 0044, and IRAS 19012 + 0536. The sources were selected from the 2002 list of Sridharan et al. and are characterized by high FIR luminosity, dense molecular and dust condensations, massive large-scale CO flows, and the absence of strong cm continuum emission. These properties are indicative of massive star-forming regions in an evolutionary phase prior to ultra- or hypercompact H II regions. We detect a total of 10 individual 1.3 cm continuum sources toward this sample, and derive in-band spectral indices between 19.3 and 25.5 GHz consistent with thermal free-free emission, for all sources except component A in IRAS 18182 - 1433, which has a negative spectral index indicative of synchrotron emission. We suggest that in most cases the 1.3 cm sources are due to shock-induced ionization, rather than direct photoionization by massive objects. The momentum rate present in these ionized flows is sufficient to drive the large-scale molecular flows. We discuss a number of morphological features supporting this hypothesis. The present observations demonstrate that the EVLA has sufficient sensitivity to study the regions near very young massive stars in the cm continuum.

Hofner, P. [Physics Department, New Mexico Tech, 801 Leroy Pl., Socorro, NM 87801 (United States); Kurtz, S.; Loinard, L.; RodrIguez, L. F. [Centro de RadioastronomIa y Astrofisica, P.O. Box 3-72 Universidad Nacional Autonoma de Mexico, Morelia 58090 (Mexico); Ellingsen, S. P. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, Tasmania 7001 (Australia); Menten, K. M.; Wyrowski, F. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Araya, E. D. [Physics Department, Western Illinois University, 1 University Circle, Macomb, IL 61455 (United States); Cesaroni, R. [INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze (Italy)

2011-09-20

144

Observations of Flow and Sediment Entrainment on a Large Gravel-Bed River  

NASA Astrophysics Data System (ADS)

Constant-discharge reservoir releases on the Trinity River, California, provide an unusual opportunity to unambiguously relate flow and gravel entrainment on a large gravel-bed river. Bed shear stress ?0 was estimated using local observations of depth-averaged velocity. Gravel entrainment was measured using large tracer gravel installations. Lateral variability of ?0 is large, even for straight channels with simple, trough-like geometry. No simple relation exists between local and cross-section mean values of ?0 . Fine grains (less than 8 mm; 20-30% of the bed material) are transported at lower discharges than coarse grains. Scour to the base of the bed surface layer occurs at a dimensionless shear stress ?g* ? 0.035, for ?g* formed using local ?0 and the median grain size of the gravel portion of the bed. The dimensionless reference transport rate W* = 0.002, often used as a surrogate for the threshold of grain motion, occurs at nearly the same ?g*. At smaller ?g*, entrainment and transport rates decrease rapidly, becoming vanishingly small at ?g* ? 0.031. Even at very small gravel transport rates, all sizes are transported, although the coarsest sizes are in a state of partial transport in which only a portion of the exposed grains are entrained. Both entrainment and cumulative transport observations suggest that maximum scour depth for plane-bed transport is slightly less than twice the surface layer thickness.

Wilcock, Peter R.; Barta, Alan F.; Shea, Conor C.; Kondolf, G. Mathias; Matthews, W. V. Graham; Pitlick, John

1996-04-01

145

CONTEMPORANEOUS VLBA 5 GHz OBSERVATIONS OF LARGE AREA TELESCOPE DETECTED BLAZARS  

SciTech Connect

The radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA). In total, 232 sources were observed with the VLBA. Ninety sources that were previously observed as part of the VLBA Imaging and Polarimetry Survey (VIPS) have been included in the sample, as well as 142 sources not found in VIPS. This very large, 5 GHz flux-limited sample of active galactic nuclei (AGNs) provides insights into the mechanism that produces strong {gamma}-ray emission. In particular, we see that {gamma}-ray emission is related to strong, uniform magnetic fields in the cores of the host AGN. Included in this sample are non-blazar AGNs such as 3C84, M82, and NGC 6251. For the blazars, the total VLBA radio flux density at 5 GHz correlates strongly with {gamma}-ray flux. The LAT BL Lac objects tend to be similar to the non-LAT BL Lac objects, but the LAT flat-spectrum radio quasars (FSRQs) are significantly different from the non-LAT FSRQs. Strong core polarization is significantly more common among the LAT sources, and core fractional polarization appears to increase during LAT detection.

Linford, J. D.; Taylor, G. B. [Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131-0001 (United States); Romani, R. W. [Department of Physics, Stanford University, Stanford, CA 94305 (United States); Helmboldt, J. F. [Naval Research Laboratory, Code 7213, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Readhead, A. C. S.; Reeves, R.; Richards, J. L. [Astronomy Department, California Institute of Technology, Mail Code 247-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2012-01-10

146

The Large Aperture Gamma Ray Observatory as an Observational Alternative at High Altitude  

NASA Astrophysics Data System (ADS)

Although satellite observations have revealed some mysteries about the origin and location of cosmic rays at low energies, questions remain to be resolved in higher energy ranges (>1 GeV). However, the flow of particles at high energies is very low, large sensitive areas are necessary, so that the detection of secondary particles from observatories on the surface of the earth is a technically viable solution. While the Pierre Auger Observatory has such capacity given its 16000 m^2 of detectors, low height above sea level greatly reduces its detection capability. The Large Aperture Gamma Ray Observatory (LAGO) is an observational alternative that attempts to overcome this limitation. This project was started in 2005, placing water Cherenkov Detectors at high altitude. Observation sites have been selected with some basic requirements: altitude, academic and technical infrastructure, existence of a research group responsible for assembly and maintenance of the detectors and the analysis, visualization, divulgation and data storage. This paper presents the general status of the observatories of Sierra Negra-México, Chacaltaya-Bolívia, Marcapomacocha-Perú, Mérida-Venezuela and Bucaramanga-Colombia.

Rosales, M.

2011-10-01

147

Large scale galactic turbulence: can self-gravity drive the observed HI velocity dispersions?  

E-print Network

Observations of turbulent velocity dispersions in the HI component of galactic disks show a characteristic floor in galaxies with low star formation rates and within individual galaxies the dispersion profiles decline with radius. We carry out several high resolution adaptive mesh simulations of gaseous disks embedded within dark matter haloes to explore the roles of cooling, star-formation, feedback, shearing motions and baryon fraction in driving turbulent motions. In all simulations the disk slowly cools until gravitational and thermal instabilities give rise to a multi-phase medium in which a large population of dense self-gravitating cold clouds are embedded within a warm gaseous phase that forms through shock heating. The diffuse gas is highly turbulent and is an outcome of large scale driving of global non-axisymmetric modes as well as cloud-cloud tidal interactions and merging. At low star-formation rates these processes alone can explain the observed HI velocity dispersion profiles and the characteristic value of ~10 km/s observed within a wide range of disk galaxies. Supernovae feedback creates a significant hot gaseous phase and is an important driver of turbulence in galaxies with a star-formation rate per unit area >10^-3 M_sun/yr/kpc^2.

Oscar Agertz; George Lake; Romain Teyssier; Ben Moore; Lucio Mayer; Alessandro B. Romeo

2008-10-09

148

Expanded Very Large Array Nova Project Observations of the Classical NovaV1723 Aquilae  

NASA Technical Reports Server (NTRS)

We present radio light curves and spectra of the classical nova VI723 Aql obtained with the Expanded Very Large Array (EVLA). This is the first paper to showcase results from the EVLA Nova Project, which comprises a team of observers and theorists utilizing the greatly enhanced sensitivity and frequency coverage of EVLA radio observations, along with observations at other wavelengths, to reach a deeper understanding of the energetics, morphology, and temporal characteristics of nova explosions. Our observations of VI723 Aql span 1-37 GHz in frequency, and we report on data from 14 to 175 days following the time of the nova explosion. The broad frequency coverage and frequent monitoring show that the radio behavior of VI723 Aql does not follow the classic Hubble-flow model of homologous spherically expanding thermal ejecta. The spectra are always at least partially optically thin, and the flux rises on faster timescales than can be reproduced with linear expansion. Therefore, any description of the underlying physical processes must go beyond this simple picture. The unusual spectral properties and light curve evolution might be explained by multiple emitting regions or shocked material. Indeed, X-ray observations from Swift reveal that shocks are likely present.

Krauss, Miriam I.; Chomiuk, Laura; Rupen, Michael; Roy, Nirupam; Mioduszewski, Amy J.; Sokoloski, J. L.; Nelson, Thomas; Mukai, Koji; Bode, M. F.; Eyres, S. P. S.; OBrien, T. J.

2011-01-01

149

Large oxidation dependence observed in terahertz dielectric response for cytochrome c  

NASA Astrophysics Data System (ADS)

Far infrared dielectric response is used to characterize the collective mode density of states for cytochrome c as a function of oxidation state and hydration using terahertz time domain spectroscopy. A strong absorbance and refractive index increase was observed with the oxidation. A simple phenomenological fitting using a continuous distribution of oscillators reproduces the frequency dependence of the complex dielectric response as well as demonstrates quantitative agreement with a uniform increase in either mode density or polarizability with oxidation in the 5-80cm-1 frequency range. Hydration dependence measurements find that a difference in the equilibrium water content for ferri and ferro cytochrome c is not sufficient to account for the large change in terahertz response. The large dielectric increase at terahertz frequencies with oxidation suggests either a significant global softening of the potential and/or a significant increase in polarizability with oxidation.

Chen, J.-Y.; Knab, J. R.; Cerne, J.; Markelz, A. G.

2005-10-01

150

Large Amplitude Dynamic Events Near the Mesopause Observed in Na Lidar Measured Wind, Temperature, and Density  

NASA Astrophysics Data System (ADS)

Large amplitude dynamic events are frequently observed in the 85-105 km altitude region in data from Starfire, NM, Maui, HA, and Urbana, IL. Similar events at Maui have been analyzed by Larsen et al., [2004, J. Geophys. Res., 109, doi:10.1029/2002JF003067] and Hurd et al. [CEDAR poster, Utah, 2008] from Na lidar data. The events have a vertical extent of large temperature anomalies over 4-6 km, with a period of 3- 6 hours. All the events consist of a cold (upwelling) followed by a warm (downwelling) phase. Na density enhancements and depletions above the events as well as the horizontal winds provide insights into the cause for specific events (i.e. Li et al. , 2007, Investigation of a "wall" wave event, J. Geophys. Res., 112, doi10.1029/2006JD007213).

Swenson, G. R.; Liu, A.; Carlson, C.; Lu, X.; Mangognia, T.; Li, Z.

2008-12-01

151

IRAS observations of a large circumstellar dust shell around W Hydrae  

NASA Technical Reports Server (NTRS)

IRAS observations at 60 and 100 microns reveal a large 30-40-arcmin (about 1-pc) diameter dust shell centered on the oxygen-rich red giant W Hya. Except for SNRs, this is the largest mass-loss envelope, in apparent diameter, known around any evolved star, including PN. W Hya's radiation field, stronger than the interstellar radiation field in the outer envelope, is sufficient to heat dust grains with IR emissivity proportional to lambda exp -1.2 to temperatures of about 40 K implied by the ratio of intensities at 60 and 100 microns.

Hawkins, G. W.

1990-01-01

152

The REFLEX Cluster Survey: Observing Strategy and First Results on Large-Scale Structure  

E-print Network

We give a general description of the optical observing strategy of the ROSAT-ESO Flux-Limited X-ray (REFLEX) cluster survey. This presently includes 460 clusters of galaxies selected from the ROSAT All-Sky Survey in the Southern hemisphere, to a flux limit of 3 10^{-12} erg s^{-1} cm^{-2}. Redshifts are now measured for 95% of this sample. Work is in progress to complete this coverage, and then extend the sample to fainter fluxes. A few highlights on the large-scale distribution of REFLEX clusters and their clustering properties are also discussed.

L. Guzzo; H. Boehringer; P. Schuecker; C. A. Collins; S. Schindler; D. M. Neumann; S. De Grandi; R. Cruddace; G. Chincarini; A. C. Edge; P. A. Shaver; W. Voges

1999-03-25

153

Fermi Large Area Telescope Observations of the Cosmic-Ray Induced  

SciTech Connect

We report on measurements of the cosmic-ray induced {gamma}-ray emission of Earth's atmosphere by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. The LAT has observed the Earth during its commissioning phase and with a dedicated Earth-limb following observation in September 2008. These measurements yielded {approx} 6.4 x 10{sup 6} photons with energies > 100 MeV and {approx} 250 hours total livetime for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission - often referred to as Earth albedo gamma-ray emission - has a power-law shape up to 500 GeV with spectral index {Lambda} = 2.79 {+-} 0.06.

Abdo, A.

2012-02-29

154

Strong circular photogalvanic effect in ZnO epitaxial films  

SciTech Connect

A strong circular photogalvanic effect (CPGE) in ZnO epitaxial films was reported under interband excitation. It was observed that CPGE current is as large as 100 nA/W in ZnO, which is about one order in magnitude higher than that in InN film while the CPGE currents in GaN films are not detectable. The possible reasons for the above observations are the strong spin orbit coupling in ZnO or the inversed valence band structure of ZnO.

Zhang, Q.; Wang, X. Q.; Yin, C. M.; Shen, B. [State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Chen, Y. H.; Chang, K. [Laboratory of Semiconductor Materials Science, Institute of Semiconductors, CAS, Beijing 100083 (China); Ge, W. K. [Department of Physics, Tsinghua University, Beijing 100871 (China)

2011-12-23

155

Circular Membrane Modes Model  

NSDL National Science Digital Library

The Circular Membrane Modes model displays the analytical wave equation solution for an ideal circular membrane with a fixed boundary. The solution is described by two integers m and n where n is a positive integer that counts the number of radial nodes and m counts the number of azimuthal (angular) nodes. The model shows a time-dependent animation of the membrane displacement and Chladni-like nodal pattern. The Circular Membrane Modes model is a supplemental simulation for the article "Chladni Patterns on Drumheads: A Physics of Music Experiment" by Randy Worland in The Physics Teacher 49(1), 24-27 (2011) and has been approved by the authors and The Physics Teacher editor. The model was developed using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_mech_CircularMembraneModes.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-10-11

156

LABORATORY IV CIRCULAR MOTION  

E-print Network

objects moving in uniform circular motion. This is the same motion that describes satellites in orbit's instantaneous and average velocity and acceleration from video images. · Analyze a vector in terms of its

Minnesota, University of

157

Large Amplitude Whistlers in the Magnetosphere Observed with Wind-Waves  

NASA Technical Reports Server (NTRS)

We describe the results of a statistical survey of Wind-Waves data motivated by the recent STEREO/Waves discovery of large-amplitude whistlers in the inner magnetosphere. Although Wind was primarily intended to monitor the solar wind, the spacecraft spent 47 h inside 5 R(sub E) and 431 h inside 10 R(sub E) during the 8 years (1994-2002) that it orbited the Earth. Five episodes were found when whistlers had amplitudes comparable to those of Cattell et al. (2008), i.e., electric fields of 100 m V/m or greater. The whistlers usually occurred near the plasmapause. The observations are generally consistent with the whistlers observed by STEREO. In contrast with STEREO, Wind-Waves had a search coil, so magnetic measurements are available, enabling determination of the wave vector without a model. Eleven whistler events with useable magnetic measurements were found. The wave vectors of these are distributed around the magnetic field direction with angles from 4 to 48deg. Approximations to observed electron distribution functions show a Kennel-Petschek instability which, however, does not seem to produce the observed whistlers. One Wind episode was sampled at 120,000 samples/s, and these events showed a signature that is interpreted as trapping of electrons in the electrostatic potential of an oblique whistler. Similar waveforms are found in the STEREO data. In addition to the whistler waves, large amplitude, short duration solitary waves (up to 100 mV/m), presumed to be electron holes, occur in these passes, primarily on plasma sheet field lines mapping to the auroral zone.

Kellogg, P. J.; Cattell, C. A.; Goetz, K.; Monson, S. J.; Wilson, L. B., III

2011-01-01

158

Squaring a Circular Segment  

ERIC Educational Resources Information Center

Consider a circular segment (the smaller portion of a circle cut off by one of its chords) with chord length c and height h (the greatest distance from a point on the arc of the circle to the chord). Is there a simple formula involving c and h that can be used to closely approximate the area of this circular segment? Ancient Chinese and Egyptian…

Gordon, Russell

2008-01-01

159

ANZUELOS CIRCULARES VS. ANZUELOS \\  

Microsoft Academic Search

SUMMARY The use of circular hooks in pelagic longline fisheries has been proposed as a method to reduce the incidental catch of sea turtles. Experiments were carried out on the Uruguayan longline fleet to compare the catch using circular hooks (18\\/0, 10º offset) and conventional J type (9\\/0) hooks. This experiment was carried out on board an industrial longliner fishing

Andrés Domingo; Caren Barceló; Yonat Swimmer; Maite Pons; Philip Miller

160

Estimating the impact of satellite observations on the predictability of large-scale hydraulic models  

NASA Astrophysics Data System (ADS)

Large-scale hydraulic models are able to predict flood characteristics, and are being used in forecasting applications. In this work, the potential value of satellite observations to initialize hydraulic forecasts is explored, using the Ensemble Sensitivity method. The impact estimation is based on the Local Ensemble Transform Kalman Filter, allowing for the forecast error reductions to be computed without additional model runs. The experimental design consisted of two configurations of the LISFLOOD-FP model over the Ohio River basin: a baseline simulation represents a “best effort” model using observations for parameters and boundary conditions, whereas the second simulation consists of erroneous parameters and boundary conditions. Results showed that the forecast skill was improved for water heights up to lead times of 11 days (error reductions ranged from 0.2 to 0.6 m/km), while even partial observations of the river contained information for the entire river's water surface profile and allowed forecasting 5 to 7 days ahead. Moreover, water height observations had a negative impact on discharge forecasts for longer lead times although they did improve forecast skill for 1 and 3 days (up to 60 m3/s/km). Lastly, the inundated area forecast errors were reduced overall for all examined lead times. Albeit, when examining a specific flood event the limitations of predictability were revealed suggesting that model errors or inflows were more important than initial conditions.

Andreadis, Konstantinos M.; Schumann, Guy J.-P.

2014-11-01

161

CARMA Large Area Star Formation Survey: Observational Analysis of Filaments in the Serpens South Molecular Cloud  

E-print Network

We present the N2H+(J=1-0) map of the Serpens South molecular cloud obtained as part of the CARMA Large Area Star Formation Survey (CLASSy). The observations cover 250 square arcminutes and fully sample structures from 3000 AU to 3 pc with a velocity resolution of 0.16 km/s, and they can be used to constrain the origin and evolution of molecular cloud filaments. The spatial distribution of the N2H+ emission is characterized by long filaments that resemble those observed in the dust continuum emission by Herschel. However, the gas filaments are typically narrower such that, in some cases, two or three quasi-parallel N2H+ filaments comprise a single observed dust continuum filament. The difference between the dust and gas filament widths casts doubt on Herschel ability to resolve the Serpens South filaments. Some molecular filaments show velocity gradients along their major axis, and two are characterized by a steep velocity gradient in the direction perpendicular to the filament axis. The observed velocity gra...

Fernández-López, M; Looney, L; Mundy, L G; Storm, S; Teuben, P J; Lee, K; Segura-Cox, D; Isella, A; Tobin, J J; Rosolowsky, E; Plunkett, A; Kwon, W; Kauffmann, J; Ostriker, E; Tassis, K; Shirley, Y L; Pound, M

2014-01-01

162

VERY LARGE ARRAY OBSERVATIONS OF DG TAU'S RADIO JET: A HIGHLY COLLIMATED THERMAL OUTFLOW  

SciTech Connect

The active young protostar DG Tau has an extended jet that has been well studied at radio, optical, and X-ray wavelengths. We report sensitive new Very Large Array (VLA) full-polarization observations of the core and jet between 5 GHz and 8 GHz. Our high angular resolution observation at 8 GHz clearly shows an unpolarized inner jet with a size of 42 AU (0.''35) extending along a position angle similar to the optical-X ray outer jet. Using our nearly coeval 2012 VLA observations, we find a spectral index {alpha} = +0.46 {+-} 0.05, which combined with the lack of polarization is consistent with bremsstrahlung (free-free) emission, with no evidence for a non-thermal coronal component. By identifying the end of the radio jet as the optical depth unity surface, and calculating the resulting emission measure, we find that our radio results are in agreement with previous optical line studies of electron density and consequent mass-loss rate. We also detect a weak radio knot at 5 GHz located 7'' from the base of the jet, coincident with the inner radio knot detected by Rodriguez et al. in 2009 but at lower surface brightness. We interpret this as due to expansion of post-shock ionized gas in the three years between observations.

Lynch, C.; Mutel, R. L.; Gayley, K. G. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52240 (United States)] [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52240 (United States); Guedel, M. [Department of Astrophysics, University of Vienna, A-1180 Vienna (Austria)] [Department of Astrophysics, University of Vienna, A-1180 Vienna (Austria); Ray, T. [Astronomy and Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland)] [Astronomy and Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2 (Ireland); Skinner, S. L. [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States)] [Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309 (United States); Schneider, P. C. [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)] [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

2013-03-20

163

BATSE Observations of the Large-Scale Isotropy of Gamma-Ray Bursts  

NASA Technical Reports Server (NTRS)

We use dipole and quadrupole statistics to test the large-scale isotropy of the first 1005 gamma-ray bursts observed by the Burst and Transient Source Experiment (BATSE). In addition to the entire sample of 1005 gamma-ray bursts, many subsets are examined. We use a variety of dipole and quadrupole statistics to search for Galactic and other predicted anisotropies and for anisotropies in a coordinate-system independent manner. We find the gamma-ray burst locations to be consistent with isotropy, e.g., for the total sample the observed Galactic dipole moment (cos theta) differs from the value predicted for isotropy by 0.9 sigma and the observed Galactic quadrupole moment (sin(exp 2) b - 1/3) by 0.3 sigma. We estimate for various models the anisotropies that could have been detected. If one-half of the locations were within 86 deg of the Galactic center, or within 28 deg of the Galactic plane, the ensuing dipole or quadrupole moment would have typically been detected at the 99% confidence level. We compare the observations with the dipole and quadrupole moments of various Galactic models. Several Galactic gamma-ray bursts models have moments within 2 sigma of the observations; most of the Galactic models proposed to date are no longer in acceptable agreement with the data. Although a spherical dark matter halo distribution could be consistent with the data, the required core radius is larger than the core radius of the dark matter halo used to explain the Galaxy's rotation curve. Gamma-ray bursts are much more isotropic than any observed Galactic population, strongly favoring but not requiring an origin at cosmological distances.

Briggs, Michael S.; Paciesas, William S.; Pendleton, Geoffrey N.; Meegan, Charles A.; Fishman, Gerald J.; Horack, John M.; Brock, Martin N.; Kouveliotou, Chryssa; Hartmann, Dieter H.; Hakkila, Jon

1996-01-01

164

The genome of Oryctes rhinoceros nudivirus provides novel insight into the evolution of nuclear arthropod-specific large circular double-stranded DNA viruses.  

PubMed

The Oryctes rhinoceros nudivirus (OrNV) is a dsDNA virus with enveloped, rod-shaped virions. Its genome is 127,615 bp in size and contains 139 predicted protein-coding open reading frames (ORFs). In-depth genome sequence comparisons revealed a varying number of shared gene homologues, not only with other nudiviruses (NVs) and baculoviruses, but also with other arthropod-specific large dsDNA viruses, including the so-called Monodon baculovirus (MBV), the salivary gland hypertrophy viruses (SGHVs) and white spot syndrome virus (WSSV). Nudivirus genomes contain 20 baculovirus core gene homologues associated with transcription (p47, lef-8, lef-9, lef-4, vlf-1, and lef-5), replication (dnapol and helicase), virus structure (p74, pif-1, pif-2, pif-3, 19kda/pif-4, odv-e56/pif-5, vp91, vp39, and 38K), and unknown functions (ac68, ac81, and p33). Most strikingly, a set of homologous genes involved in peroral infection (p74, pif-1, pif-2, and pif-3) are common to baculoviruses, nudiviruses, SGHVs, and WSSV indicating an ancestral mode of infection in these highly diverged viruses. A gene similar to polyhedrin/granulin encoding the baculovirus occlusion body protein was identified in non-occluded NVs and in Musca domestica SGHV evoking the question of the evolutionary origin of the baculovirus polyhedrin/granulin gene. Based on gene homologies, we further propose that the shrimp MBV is an occluded member of the nudiviruses. We conclude that baculoviruses, NVs and the shrimp MBV, the SGHVs and WSSV share the significant number of conserved genetic functions, which may point to a common ancestry of these viruses. PMID:21380757

Wang, Yongjie; Bininda-Emonds, Olaf R P; van Oers, Monique M; Vlak, Just M; Jehle, Johannes A

2011-06-01

165

A Large Biogenic Source of Formic Acid Revealed From Space Observations  

NASA Astrophysics Data System (ADS)

Formic acid (HCOOH) is a ubiquitous trace gas in ambient air and a major contributor to acidic rain in remote environments. Its sources, however, are far from being fully understood. Along with direct emissions from human activities, vegetation fires and green plants, its major and most uncertain source is photochemical, and predominantly biogenic. Severe underpredictions of observed formic acid concentrations by large scale models in earlier studies pointed to the existence of missing sources. New insights into our understanding of the formic acid budget are brought forward by recent measurements of global tropospheric columns of formic acid retrieved from the thermal infrared IASI satellite sensor. In this communication, we use the IASI observations as input to an advanced source inversion algorithm coupled with a global chemistry transport model to build constraints on the formic acid budget. We deduce an annual formic acid source much higher than estimated from known sources, with a biogenic contribution of about 90%, mostly from tropical and boreal forests. We evaluate the derived fluxes against an extensive compilation of independent formic acid measurements, and investigate the implications of the large formic acid source on precipitation acidity on the global scale.

Stavrakou, T.; Muller, J. J.; Peeters, J.; Razavi, A.; Clarisse, L.; Clerbaux, C.; Coheur, P.; Hurtmans, D.

2011-12-01

166

Confronting the relaxation mechanism for a large cosmological constant with observations  

E-print Network

In order to deal with a large cosmological constant a relaxation mechanism based on modified gravity has been proposed recently. By virtue of this mechanism the effect of the vacuum energy density of a given quantum field/string theory (no matter how big is its initial value in the early universe) can be neutralized dynamically, i.e. without fine tuning, and hence a Big Bang-like evolution of the cosmos becomes possible. Remarkably, a large class F^n_m of models of this kind, namely capable of dynamically adjusting the vacuum energy irrespective of its value and size, has been identified. In this paper, we carefully put them to the experimental test. By performing a joint likelihood analysis we confront these models with the most recent observational data on type Ia supernovae (SNIa), the Cosmic Microwave Background (CMB), the Baryonic Acoustic Oscillations (BAO) and the high redshift data on the expansion rate, so as to determine which ones are the most favored by observations. We compare the optimal relaxation models F^n_m found by this method with the standard or concordance LambdaCDM model, and find that some of these models may appear as almost indistinguishable from it. Interestingly enough, this shows that it is possible to construct viable solutions to the tough cosmological fine tuning problem with models that display the same basic phenomenological features as the concordance model.

Spyros Basilakos; Florian Bauer; Joan Sola

2011-09-22

167

Confronting the relaxation mechanism for a large cosmological constant with observations  

SciTech Connect

In order to deal with a large cosmological constant a relaxation mechanism based on modified gravity has been proposed recently. By virtue of this mechanism the effect of the vacuum energy density of a given quantum field/string theory (no matter how big is its initial value in the early universe) can be neutralized dynamically, i.e. without fine tuning, and hence a Big Bang-like evolution of the cosmos becomes possible. Remarkably, a large class (F{sup n}{sub m}) of models of this kind, namely capable of dynamically adjusting the vacuum energy irrespective of its value and size, has been identified. In this paper, we carefully put them to the experimental test. By performing a joint likelihood analysis we confront these models with the most recent observational data on type Ia supernovae (SNIa), the Cosmic Microwave Background (CMB), the Baryonic Acoustic Oscillations (BAO) and the high redshift data on the expansion rate, so as to determine which ones are the most favored by observations. We compare the optimal relaxation models F{sup n}{sub m} found by this method with the standard or concordance ?CDM model, and find that some of these models may appear as almost indistinguishable from it. Interestingly enough, this shows that it is possible to construct viable solutions to the tough cosmological fine tuning problem with models that display the same basic phenomenological features as the concordance model.

Basilakos, Spyros; Bauer, Florian; Solà, Joan, E-mail: svasil@academyofathens.gr, E-mail: fbauerphysik@eml.cc, E-mail: sola@ecm.ub.es [High Energy Physics Group, Dept. ECM, Univ. de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Catalonia (Spain)

2012-01-01

168

The characteristics of quasistatic electric field perturbations observed by DEMETER satellite before large earthquakes  

NASA Astrophysics Data System (ADS)

This paper presents new results after processing the ULF electric field (DC-15 Hz) observed by DEMETER satellite (h = 660-710 km). Typical perturbations were picked up in quasistatic electric field around some large earthquakes in 2010 at first. And then, 27 earthquakes were selected to be analyzed on quasistatic electric field in two seismic regions of Indonesia and Chile at equatorial and middle latitude area respectively. Three-component electric field data related to earthquakes were collected along all the up-orbits (in local nighttime) in a limited distance of 2000 km to the epicenters during 9 days with 7 days before and 1 day after those cases, and totally 57 perturbations were found around them. All the results show that the amplitude of quasistatic electric field perturbations varies from 1.5 to 16 mV/m in the upper ionosphere, mostly smaller than 10 mV/m. And the perturbations were mainly located just over the epicentral area or at the end of seismic faults constructed by a series of earthquakes where electromagnetic emissions may be easily formed during preparation and development processes of seismic sequences. Among all 27 cases, there are 10 earthquakes with perturbations occurring just one day before, which demonstrates the close correlation in time domain between quasistatic electric field in ionosphere and large earthquakes. Finally, combined with in situ observation of plasma parameters, the coupling mechanism of quasistatic electric field in different earth spheres was discussed.

Zhang, X.; Shen, X.; Zhao, S.; Yao, Lu; Ouyang, X.; Qian, J.

2014-01-01

169

Circular Sound Wave Scattering Derivation for Acoustic Cloak Detection  

E-print Network

In this Letter we develop analytical formulations to describe sound scattering in lossless medium due to 2D circular wave incident on an acoustic cloak. A perfect acoustic cloak is reflectionless and can completely hide the cloaked object from any sound waves. However, the realization of a perfect acoustic cloak is difficult. Compared to plane wave, our analytic calculations show that circular wave from an annular line source generates distinct scattering patterns from an imperfect cloak design. Large modification in reflection directivities can be observed if the focal point of the incident wavefront is slightly customized. Hence, our work might find applications in acoustic cloak detection, which should have significant impact on cloak design and defense.

Zhong, Siyang

2012-01-01

170

Extremely Large Diamagnetic Cavities Observed In The Dayside High-altitute Cusps  

NASA Astrophysics Data System (ADS)

Some extremely large diamagnetic cavities have been observed in April, 1999 when the POLAR spacecraft was crossing through the dayside high-altitude cusp regions. These diamagnetic cavities were associated with strong magnetic field turbulence. Some of the diamagnetic cavities were independent of the IMF directions, which is unexpected by the current MHD models, suggesting that the diamagnetic cavities are different from the magnetospheric sash. The size of the cavities were found to be as large as 6 Re. Associated with these cavities are ions with energies from 40 keV up to 8 MeV that are more typical of the trapped ring current and radiation belt populations than the solar wind. The intensities of the energetic ions were observed to increase by as large as four orders of the magnitudes during the cavity crossings, indicating the dayside high-altitude cusp diamagnetic cavity is a key region for transferring the solar wind energy, mass, and momentum into the Earth's magnetosphere. The charge state distribution of these cusp cavity ions was indicative of their seed populations being a mixture of the ionospheric and the solar wind particles. By their geometry cusp mag- netic field lines are connected to all of the magnetopause boundary layers and these cavity charged particles will form an energetic particle layer on the magnetopause. These energetic particles in the cusp diamagnetic cavity together with the cusp's con- nectivity have significant global impacts on the geospace environment research and will be shedding light on the long-standing unsolved fundamental issue about the ori- gins of the energetic particles in the ring current and in upstream ion events.

Chen, Jiasheng; Fritz, Theodore A.

171

Rapid formation of large aggregates during the spring bloom of Kerguelen Island: observations and model comparisons  

NASA Astrophysics Data System (ADS)

While production of aggregates and their subsequent sinking is known to be one pathway for the downward movement of organic matter from the euphotic zone, the rapid transition from non-aggregated to aggregated particles has not been reported previously. We made one vertical profile of particle size distributions (PSD; sizes ranging from 0.052 to several millimeters in equivalent spherical diameter) at pre-bloom stage and seven vertical profiles 3 weeks later over a 48 h period at early bloom stage using the Underwater Vision Profiler during the Kerguelen Ocean and Plateau Compared Study cruise 2 (KEOPS2, October-November 2011). In these naturally iron-fertilized waters southeast of Kerguelen Island (Southern Ocean), the total particle numerical abundance increased by more than fourfold within this time period. A massive total volume increase associated with particle size distribution changes was observed over the 48 h survey, showing the rapid formation of large particles and their accumulation at the base of the mixed layer. The results of a one-dimensional particle dynamics model support coagulation as the mechanism responsible for the rapid aggregate formation and the development of the VT subsurface maxima. The comparison of VT profiles between early bloom stage and pre-bloom stage indicates an increase of particulate export below 200 m when bloom has developed. These results highlight the role of coagulation in forming large particles and triggering carbon export at the early stage of a naturally iron-fertilized bloom, while zooplankton grazing may dominate later in the season. The rapid changes observed illustrate the critical need to measure carbon export flux with high sampling temporal resolution. Our results are the first published in situ observations of the rapid accumulation of marine aggregates and their export and the general agreement of this rapid event with a model of phytoplankton growth and coagulation.

Jouandet, M.-P.; Jackson, G. A.; Carlotti, F.; Picheral, M.; Stemmann, L.; Blain, S.

2014-08-01

172

Very Large Array Observations of High-Velocity H I in L1551  

NASA Astrophysics Data System (ADS)

We report Very Large Array (VLA) observations of the 21 cm continuum and H I line emission of the neutral wind in the prototypical molecular outflow source L1551. The intermediate-velocity gas observed with the VLA has a velocity with respect to the ambient cloud in the range 10-50 km s-1. Although the blueshifted flow appears weaker than the red one, the maps are indicative of a bipolar morphology confined inside the large-scale CO bipolar lobes. This morphology strongly suggests that the atomic wind is driving the bipolar CO outflow. We fit to the H I line profiles, at four different positions along the redshifted flow axis, a model of a decelerating conical wind that entrains ambient cloud material in a mixing layer at the walls of the cone. This model has a velocity at the axis v0=200 km s-1, a mass-loss rate M*~=9×10-7 Msolar yr-1, and a momentum rate P~=2×10-4 Msolar yr-1 km s-1. This is sufficient to drive the observed molecular flow, provided an age >=8×104 yr. We find that the continuum emission spectrum of IRS 5, on scales of 10", is similar to those of H II regions. This can be explained if most of the emission comes from material ionized by UV radiation from shock fronts due to the interaction of the stellar wind against the ambient cloud. The momentum rate required to produce the extended centimeter emission agrees well with the wind P obtained by fitting the line profiles. Finally, the location of a background extragalactic continuum source in the red lobe allows us to probe the physical conditions of the neutral wind. We find that the most probable H I spin temperature in the wind is in the range 25-50 K, in agreement with predictions of the thermal structure of such winds.

Giovanardi, C.; Rodríguez, L. F.; Lizano, S.; Cantó, J.

2000-08-01

173

From Large Scale Surveys of the Galaxy to High Resolution Observations with ALMA  

NASA Astrophysics Data System (ADS)

A CS(2-1) survey of OB star forming regions provides statistics of their distribution in the Galaxy. The complete scenario of massive star formation for one particular GMC, at a distance of 1.6 kpc, is revealed through 1.2 mm continuum observations for spatial scales from 1 pc to 50 pc. Using large scale CO and C18O maps from NANTEN at 2.5' resolution, we identified toward the peak of C18O one of the most luminous regions of high-mass star formation in the Galaxy, G331.5, toward the tangent of Norma spiral arm, at a distance of 7.5 kpc. Observations at 1.2 mm continuum emission with SIMBA at SEST reveal the presence of a cluster of six massive millimeter clumps, with high bolometric luminosity, making G331.5 one of the most densely populated GMC cores known so far. High density molecular tracers reveal the presence, in the center of the most massive clump, of a compact, highly massive and energetic molecular outflow, with a velocity width reaching 160 km s-1 (fwzp). Further interferometric continuum observations at 3.6 cm and 6 cm shows that this powerful outflow is associated with a compact radio continuum source, likely producing highly ionized stellar wind. ALMA observations were carried in band 7 to this unresolved molecular outflow. SiO and H13CO+ observations unveil a shell-like structure toward the ambient velocity of the source, evidence of an isotropic high speed wind. The derived crossing time for this source indicates that the molecular outflow in G331.5 is one of the youngest outflow found around an OB star.

Bronfman, L.; Merello, M.

2013-10-01

174

Circular free-electron laser  

DOEpatents

A high efficiency, free electron laser utilizing a circular relativistic electron beam accelerator and a circular whispering mode optical waveguide for guiding optical energy in a circular path in the circular relativistic electron beam accelerator such that the circular relativistic electron beam and the optical energy are spatially contiguous in a resonant condition for free electron laser operation. Both a betatron and synchrotron are disclosed for use in the present invention. A free electron laser wiggler is disposed around the circular relativistic electron beam accelerator for generating a periodic magnetic field to transform energy from the circular relativistic electron beam to optical energy.

Brau, Charles A. (Los Alamos, NM); Kurnit, Norman A. (Santa Fe, NM); Cooper, Richard K. (Los Alamos, NM)

1984-01-01

175

CIRCULAR RIBBON FLARES AND HOMOLOGOUS JETS  

SciTech Connect

Solar flare emissions in the chromosphere often appear as elongated ribbons on both sides of the magnetic polarity inversion line (PIL), which has been regarded as evidence of a typical configuration of magnetic reconnection. However, flares having a circular ribbon have rarely been reported, although it is expected in the fan-spine magnetic topology involving reconnection at a three-dimensional (3D) coronal null point. We present five circular ribbon flares with associated surges, using high-resolution and high-cadence H{alpha} blue wing observations obtained from the recently digitized films of Big Bear Solar Observatory. In all the events, a central parasitic magnetic field is encompassed by the opposite polarity, forming a circular PIL traced by filament material. Consequently, a flare kernel at the center is surrounded by a circular flare ribbon. The four homologous jet-related flares on 1991 March 17 and 18 are of particular interest, as (1) the circular ribbons brighten sequentially, with cospatial surges, rather than simultaneously, (2) the central flare kernels show an intriguing 'round-trip' motion and become elongated, and (3) remote brightenings occur at a region with the same magnetic polarity as the central parasitic field and are co-temporal with a separate phase of flare emissions. In another flare on 1991 February 25, the circular flare emission and surge activity occur successively, and the event could be associated with magnetic flux cancellation across the circular PIL. We discuss the implications of these observations combining circular flare ribbons, homologous jets, and remote brightenings for understanding the dynamics of 3D magnetic restructuring.

Wang Haimin; Liu Chang, E-mail: haimin.wang@njit.edu [Space Weather Research Laboratory, Center for Solar-Terrestrial Research, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States)

2012-12-01

176

Generation of bright circularly-polarized extreme ultraviolet high harmonics for magnetic circular dichroism spectroscopy  

E-print Network

Circularly-polarized extreme UV and X-ray radiation provides valuable access to the structural, electronic and magnetic properties of materials. To date, such experiments have been possible only using large-scale free-electron lasers or synchrotrons. Here we demonstrate the first bright extreme UV circularly-polarized high harmonics and use this new light source for magnetic circular dichroism measurements at the M-shell absorption edges of cobalt. This work paves the way towards element-specific imaging and spectroscopy of multiple elements simultaneously in magnetic and other chiral media with very high spatio-temporal resolution, all on a tabletop.

Kfir, Ofer; Turgut, Emrah; Knut, Ronny; Zusin, Dmitriy; Popmintchev, Dimitar; Popmintchev, Tenio; Nembach, Hans; Shaw, Justin M; Fleicher, Avner; Kapteyn, Henry; Murnane, Margaret; Cohen, Oren

2014-01-01

177

Galaxy evolution and large-scale structure in the far-infrared. I - IRAS pointed observations  

NASA Technical Reports Server (NTRS)

Redshifts for 66 galaxies were obtained from a sample of 93 60-micron sources detected serendipitously in 22 IRAS deep pointed observations, covering a total area of 18.4 sq deg. The flux density limit of this survey is 150 mJy, 4 times fainter than the IRAS Point Source Catalog (PSC). The luminosity function is similar in shape with those previously published for samples selected from the PSC, with a median redshift of 0.048 for the fainter sample, but shifted to higher space densities. There is evidence that some of the excess number counts in the deeper sample can be explained in terms of a large-scale density enhancement beyond the Pavo-Indus supercluster. In addition, the faintest counts in the new sample confirm the result of Hacking et al. (1989) that faint IRAS 60-micron source counts lie significantly in excess of an extrapolation of the PSC counts assuming no luminosity or density evolution.

Lonsdale, Carol J.; Hacking, Perry B.

1989-01-01

178

What if Charged Current Events at Large Q2 are Observed at HERA ?  

E-print Network

An excess of events at large Q2 with a positron in the final state has been observed at HERA which, if confirmed, would be a signal of new physics. It is not clear at present if a signal of comparable rate is also seen in the charged current channel (with an antineutrino in the final state). In this note we analyse the implications of the presence of such a signal in models of new physics based on contact terms, leptoquarks and squarks with R-violating decays. We find that in all cases the most likely possibility is that the charged current signal is absent. As a consequence if this signal is present the resulting indications are very selective. In particular for squarks only charged current events with multi-quark final states are possible with quite definite predictions on the spectrum of supersymmetric particles.

G. Altarelli; G. F. Giudice; M. L. Mangano

1997-05-11

179

Tracking progress: monitoring observing statistics and telescope usage at the Southern African Large telescope  

NASA Astrophysics Data System (ADS)

Monitoring the performance of a facility is critical to successful scientific operations, and even more so, for queue based telescopes such as SALT. We highlight the steps that have been undertaken in order to monitor the performance of the Southern African Large Telescope from proposal submission to on-sky observations, and finally to publication. A suite of dedicated software tools has been produced in order to monitor the performance of the telescope, weather conditions, and scientific productivity. We report on some of the key metrics for SALT since the start of science operations to provide a baseline for its current performance. After taking account that science operations only began in September 2011, the number of papers produced by SALT since that time is similar to other 8m class observatories at the beginning of their operations.

Crawford, Steven M.; Koeslag, Anthony; Romero Colmenero, Encarni; Buckley, David A. H.; Koen, Thea; Marang, Fred; Van Wyk, Veronica; Bennett, Samantha

2014-07-01

180

Observation of a Large Reaction Cross Section in the Drip-Line Nucleus {sup 22}C  

SciTech Connect

Reaction cross sections ({sigma}{sub R}) for {sup 19}C, {sup 20}C and the drip-line nucleus {sup 22}C on a liquid hydrogen target have been measured at around 40A MeV by a transmission method. A large enhancement of {sigma}{sub R} for {sup 22}C compared to those for neighboring C isotopes was observed. Using a finite-range Glauber calculation under an optical-limit approximation the rms matter radius of {sup 22}C was deduced to be 5.4+-0.9 fm. It does not follow the systematic behavior of radii in carbon isotopes with N<=14, suggesting a neutron halo. It was found by an analysis based on a few-body Glauber calculation that the two-valence neutrons in {sup 22}C preferentially occupy the 1s{sub 1/2} orbital.

Tanaka, K.; Aoi, N.; Baba, H.; Kubo, T.; Kurokawa, M.; Michimasa, S.; Motobayashi, T.; Sakurai, H.; Takeshita, E.; Takeuchi, S.; Yamada, K. [RIKEN Nishina Center, Saitama 351-0198 (Japan); Yamaguchi, T.; Suzuki, T.; Kobayashi, K.; Komuro, M.; Nakajima, S.; Shinoda, R.; Yoshitake, M. [Department of Physics, Saitama University, Saitama 338-8570 (Japan); Ohtsubo, T.; Aiba, T. [Department of Physics, Niigata University, Niigata 950-2181 (Japan)

2010-02-12

181

Observation and analysis of nonlinear vibrational relaxation of large molecules in shock waves  

NASA Astrophysics Data System (ADS)

We report the observation of highly nonlinear vibrational relaxation for a number of large molecules in shock waves, together with an attempt at a master-equation modeling of this phenomenon. In all these molecules laser-schlieren measurements show a clear and often well-resolved local maximum in the density gradient, indicating a similar maximum in the rate of energy transfer. This unexpected phenomenon is seen in the relaxation of benzene (C6H6), cubane (C8H8), cyclopropane (C3H6), furan (C4H4O), norbornadiene (C7H8), oxirane (C2H4O), and quadricyclane (C7H8). It has also been detected in cyclopentadiene (C5H6) and pyrazine (C4N2H4), as well as CF3Br and CF3Cl but in these was not well resolved. The phenomenon thus seems nearly ubiquitous; of the "large" molecules where relaxation could be resolved, only norbornene (at C7H10 the largest such molecule) exhibits a fully linear relaxation. The gradients are clearly and solely from vibrational relaxation; integrated gradients are in good agreement with thermodynamic calculations of total density change, and near-equilibrium relaxation times in pure cyclopropane and oxirane are fully consistent with overlapping ultrasonic results. It appears we are seeing a delay in the development of series coupling in these experiments. An attempt is made to model the process using a linear master equation with exponential gap probabilities having an ?(˜down) linear in energy. Although this does introduce sufficient nonlinearity through the rate coefficients to produce maxima, these and the overall gradients are consistently too small. It is suggested that inclusion of a true nonlinearity through VV transfer will be needed to explain the observations, and a possible mechanism for this is proposed.

Kiefer, John H.; Buzyna, Leonid L.; Dib, Amal; Sundaram, Sekhar

2000-07-01

182

Merged interaction regions and large-scale magnetic field fluctuations during 1991: Voyager 2 observations  

NASA Technical Reports Server (NTRS)

This paper analyzes Voyager 2 observations of the magnetic field between 33.6 AU and 36.2 AU during 1991 when extraordinary events were observed on the Sun and in the heliosphere. The magnetic field strength signal B(t) has the unusual form of two large transient merged interaction regions (MIRs) on a fluctuating background. The two MIRs moved past the spacecraft in 32 days and 18 days, respectively. The mean field strength in each transient MIR was approx. equals 2.6 times the mean field during the remaining part of the year (0.11 nT). Each of the MIRs is related to a fast stream. The magnetic field is strong throughout each stream, suggesting that the strong fields are carried by the streams as well as produced by shock and stream compression. The fluctuations in B(t) during 1991 are not multifractal, and the MIRs cannot be approximated as multifractal clusters of intense magnetic fields. The distribution of the hour-averaged magnetic field strengths is approximately lognormal over 90% of its intermediate range, and it has an exponential tail for B greater than the average magnetic field strength. The elevation angles of B have a normal distribution with a standard deviation of 16 deg +/- 4 deg. The distributions of the azimuthal angles of B in the ranges 1 deg - 180 deg and 180 deg - 360 deg are approximately normal over a more limited range, and non-Gaussian tails associated with nearly radial magnetic fields; the standard deviations are approx. equal to 40 deg. Individual sectors are present throughout most of the interval, even in the MIRs, but there is no recurrent sector pattern. A model of the large-scale fluctuations in 1991 will have to include both determinaistic and statistical factors.

Burlaga, L. F.; Ness, N. F.

1994-01-01

183

Plasma signatures in large Martian magnetic flux ropes: MARSIS/ASPERA-3 observations  

NASA Astrophysics Data System (ADS)

Cylindrical structures of highly twisted magnetic field (flux ropes) have been observed at Mars, using measurements by the MAG-ER magnetometer-electron reflectometer onboard Mars Global Surveyor (MGS) and by the MARSIS radar sounder onboard Mars Express (MEX). Signatures of flux ropes are spikes of magnetic field strength and magnetic field rotations. Both small scale flux ropes (diameters of a few tens of km) and large scale flux ropes (diameters of around 100 km) have been found at Mars. We look at times of presumed flux ropes on the dayside of Mars, detected in the local magnetic field strength given by MARSIS. The signatures in MARSIS are magnetic field strength increases (peak strength reaches several tens to hundred nT) for several minutes (size of hundreds of km along the spacecraft track), found outside but near crustal magnetic field regions. Although we cannot determine the presence of a magnetic field rotation because of the lack of a magnetometer onboard MEX, we assume that these magnetic field increases are large flux ropes. There are indeed large flux ropes with similar characteristics which were established by the magnetometer data from MGS, and thought to form by stretching and reconnection of crustal magnetic field by the solar wind. On the other hand, MEX possesses in situ ion measurements, unlike MGS. We will use the ion and electron data from the ASPERA-3 particle instrument onboard MEX in order to characterize the plasma (ionospheric only or mixing with shocked plasma?) inside the flux ropes, which will give hints on their origin.

Diéval, Catherine; Morgan, David; Duru, Firdevs; Gurnett, Donald

2014-05-01

184

FERMI LARGE AREA TELESCOPE OBSERVATIONS OF PSR J1836+5925  

SciTech Connect

The discovery of the gamma-ray pulsar PSR J1836+5925, powering the formerly unidentified EGRET source 3EG J1835+5918, was one of the early accomplishments of the Fermi Large Area Telescope (LAT). Sitting 25{sup 0} off the Galactic plane, PSR J1836+5925 is a 173 ms pulsar with a characteristic age of 1.8 million years, a spindown luminosity of 1.1 x 10{sup 34} erg s{sup -1}, and a large off-peak (OP) emission component, making it quite unusual among the known gamma-ray pulsar population. We present an analysis of one year of LAT data, including an updated timing solution, detailed spectral results, and a long-term light curve showing no indication of variability. No evidence for a surrounding pulsar wind nebula is seen and the spectral characteristics of the OP emission indicate it is likely magnetospheric. Analysis of recent XMM-Newton observations of the X-ray counterpart yields a detailed characterization of its spectrum, which, like Geminga, is consistent with that of a neutron star showing evidence for both magnetospheric and thermal emission.

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Atwood, W. B.; Belfiore, A. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M., E-mail: olr@slac.stanford.ed, E-mail: pablo@scipp.ucsc.ed, E-mail: nkawai@phys.titech.ac.j [Dipartimento di Fisica 'Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)

2010-04-01

185

Observation of Impurity Accumulation After Hydrogen Multi-Pellet Injection in Large Helical Device  

NASA Astrophysics Data System (ADS)

Impurity accumulation is studied for neutral beam-heated discharges after hydrogen multi-pellet injection in Large Helical Device (LHD). Iron density profiles are derived from radial profiles of EUV line emissions of FeXV-XXIV with the help of the collisional-radiative model. A peaked density profile of Fe23+ is simulated by using one-dimensional impurity transport code. The result indicates a large inward velocity of -6 m/s at the impurity accumulation phase. However, the discharge is not entirely affected by the impurity accumulation, since the concentration of iron impurity, estimated to be 3.3 × 10-5 to the electron density, is considerably small. On the other hand, a flat profile is observed for the carbon density of C6+, which is derived from the Zeff profile, indicating a small inward velocity of -1 m/s. These results suggest atomic number dependence in the impurity accumulation of LHD, which is similar to the tokamak result.

Dong, Chunfeng; Shigeru, Morita; Motoshi, Goto; Wang, Erhui; Gen, Motojiama; Izumi, Murakami; Ryuichi, Sakamoto; Norimasa, Yamamoto

2013-03-01

186

The circular internal hydraulic jump  

NASA Astrophysics Data System (ADS)

Circular hydraulic jumps are familiar in single layers. Here we report the discovery of similar jumps in two-layer flows. A thin jet of fluid impinging vertically onto a rigid horizontal plane surface submerged in a deep layer of less-dense miscible fluid spreads radially, and a near-circular internal jump forms within a few centimetres from the point of impact with the plane surface. A jump is similarly formed as a jet of relatively less-dense fluid rises to the surface of a deep layer of fluid, but it appears less stable or permanent in form. Several experiments are made to examine the case of a downward jet onto a horizontal plate, the base of a square or circular container. The inlet Reynolds numbers, Re, of the jet range from 112 to 1790. Initially jumps have an undular, laminar form with typically 2-4 stationary waves on the interface between the dense and less-dense layers but, as the depth of the dense layer beyond the jump increases, the transitions become more abrupt and turbulent, resulting in mixing between the two layers. During the transition to a turbulent regime, single and sometimes moving multiple cusps are observed around the periphery of jumps. A semi-empirical model is devised that relates the parameters of the laboratory experiment, i.e. flow rate, inlet nozzle radius, kinematic viscosity and reduced gravity, to the layer depth beyond the jump and the radius at which an undular jump occurs. The experiments imply that surface tension is not an essential ingredient in the formation of circular hydraulic jumps and demonstrate that stationary jumps can exist in stratified shear flows which can be represented as two discrete layers. No stationary circular undular jumps are found, however, in the case of a downward jet of dense fluid when the overlying, less-dense, fluid is stratified, but a stationary turbulent transition is observed. This has implications for the existence of stationary jumps in continuously stratified geophysical flows: results based on two-layer models may be misleading. It is shown that the Froude number at which a transition of finite width occurs in a radially diverging flow may be less than unity.

Thorpe, S. A.; Kavcic, I.

187

SDO/AIA OBSERVATIONS OF LARGE-AMPLITUDE LONGITUDINAL OSCILLATIONS IN A SOLAR FILAMENT  

SciTech Connect

We present the first Solar Dynamics Observatory/Atmospheric Imaging Assembly observations of the large-amplitude longitudinal (LAL) oscillations in the south and north parts (SP and NP) of a solar filament on 2012 April 7. Both oscillations are triggered by flare activities close to the filament. The period varies with filamentary threads, ranging from 44 to 67 minutes. The oscillations of different threads are out of phase, and their velocity amplitudes vary from 30 to 60 km s{sup -1}, with a maximum displacement of about 25 Mm. The oscillations of the SP repeat for about four cycles without any significant damping and then a nearby C2.4 flare causes the transition from the LAL oscillations of the filament to its later eruption. The filament eruption is also associated with a coronal mass ejection and a B6.8 flare. However, the oscillations of the NP damp with time and die out at last. Our observations show that the activated part of the SP repeatedly shows a helical motion. This indicates that the magnetic structure of the filament is possibly modified during this process. We suggest that the restoring force is the coupling of the magnetic tension and gravity.

Li Ting; Zhang Jun, E-mail: liting@nao.cas.cn, E-mail: zjun@nao.cas.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

2012-11-20

188

The topology of large-scale structure. III - Analysis of observations. [in universe  

NASA Technical Reports Server (NTRS)

A recently developed algorithm for quantitatively measuring the topology of large-scale structures in the universe was applied to a number of important observational data sets. The data sets included an Abell (1958) cluster sample out to Vmax = 22,600 km/sec, the Giovanelli and Haynes (1985) sample out to Vmax = 11,800 km/sec, the CfA sample out to Vmax = 5000 km/sec, the Thuan and Schneider (1988) dwarf sample out to Vmax = 3000 km/sec, and the Tully (1987) sample out to Vmax = 3000 km/sec. It was found that, when the topology is studied on smoothing scales significantly larger than the correlation length (i.e., smoothing length, lambda, not below 1200 km/sec), the topology is spongelike and is consistent with the standard model in which the structure seen today has grown from small fluctuations caused by random noise in the early universe. When the topology is studied on the scale of lambda of about 600 km/sec, a small shift is observed in the genus curve in the direction of a 'meatball' topology.

Gott, J. Richard, III; Weinberg, David H.; Miller, John; Thuan, Trinh X.; Schneider, Stephen E.

1989-01-01

189

Mechanical and hydrologic basis for the rapid motion of a large tidewater glacier. 1: Observations  

NASA Technical Reports Server (NTRS)

Measurements of glacier flow velocity and basal water pressure at two sites on Columbia Glacier, Alaska, are combined with meteorological and hydrologic data to provide an observational basis for assessing the role of water storage and basal water pressure in the rapid movement of this large glacier. During the period from July 5 to August 31, 1987, coordinated observations were made of glacier surface motion and of water level in five boreholes drilled to (or in one case near to) the glacier bed at two sites, 5 and 12 km from the terminus. Glacier velocities increased downglacier in this reach from about 4 m/d to about 7 m/d. Three types of time variation in velocity and other variables were revealed: (1) Diurnal fluctuation in water input/output, borehole water level, and ice velocity (fluctuation amplitude 5 to 8%); (2) Speed-up events in glacier motion (15-30% speed-up), lasting about three days, and ocurring at times of enhanced input of water, in some cases from rain and in others from ice ablation enhanced by strong, warm winds; (3) 'Extra-slowdown' events, in which, after a speed-up event, the ice velocity decreased in about 3 days to a level consistently lower than that prior to the speed-up event. All of the time variations were due, directly or indirectly, to variations in water input to the glacier.

Meier, Mark; Lundstrom, Scott; Stone, Dan; Kamb, Barclay; Engelhardt, Hermann; Humphrey, Neil; Dunlap, William W.; Fahnestock, Mark; Krimmel, Robert M.; Walters, Roy

1994-01-01

190

Microwave observations of late-type stars with the Very Large Array  

NASA Technical Reports Server (NTRS)

The Very Large Array was used to search for microwave emission from 32 stars of late spectral type including RS CVn type stars, dwarf M stars, and stars with active chromospheres, coronae, or intense magnetic fields. The RS CVn stars were detected at 6 cm wavelength, and upper limits are established for another six. Radio emission was detected from three dwarf M flare stars, UV Cet, EQ Peg and YZ CMi. Both impulsive (no more than 20 s) and more gradual (at least ten minutes) bursts were observed from the flare star YZ CMi. Radio emission was not confirmed at 6 cm from the solar type star Chi(1) Ori, with an upper limit that is three times lower than the detections reported by other observers. Microwave emission could not be detected from any other solar type star of spectral class F to K. The quiescent radio emission from dwarf M flare stars was interpreted as nonthermal gyrosynchrotron emission by mildly relativistic electrons accelerated more or less continuously in the magnetic fields of starspots.

Pallavicini, R.; Willson, R. F.; Lang, K. R.

1985-01-01

191

Microwave observations of late-type stars with the Very Large Array  

NASA Astrophysics Data System (ADS)

The Very Large Array was used to search for microwave emission from 32 stars of late spectral type including RS CVn type stars, dwarf M stars, and stars with active chromospheres, coronae, or intense magnetic fields. The RS CVn stars were detected at 6 cm wavelength, and upper limits are established for another six. Radio emission was detected from three dwarf M flare stars, UV Cet, EQ Peg and YZ CMi. Both impulsive (no more than 20 s) and more gradual (at least ten minutes) bursts were observed from the flare star YZ CMi. Radio emission was not confirmed at 6 cm from the solar type star Chi(1) Ori, with an upper limit that is three times lower than the detections reported by other observers. Microwave emission could not be detected from any other solar type star of spectral class F to K. The quiescent radio emission from dwarf M flare stars was interpreted as nonthermal gyrosynchrotron emission by mildly relativistic electrons accelerated more or less continuously in the magnetic fields of starspots.

Pallavicini, R.; Willson, R. F.; Lang, K. R.

1985-08-01

192

Observations of large-scale fluid transport by laser-guided plankton aggregationsa)  

NASA Astrophysics Data System (ADS)

Diel vertical migration of plankton has been proposed to affect global ocean circulation to a degree comparable to winds and tides. This biomixing process has never been directly observed, however, due to the inability to predict its occurrence in situ or to reproduce it in a laboratory setting. Furthermore, it has been argued that the energy imparted to the ocean by plankton migrations occurs at the scale of individual organisms, which is too small to impact ocean mixing. We describe the development of a multi-laser guidance system that leverages the phototactic abilities of plankton to achieve controllable vertical migrations concurrently with laser velocimetry of the surrounding flow. Measurements in unstratified fluid show that the hydrodynamic interactions between neighboring swimmers establish an alternate energy transfer route from the small scales of individually migrating plankton to significantly larger scales. Observations of laser-induced vertical migrations of Artemia salina reveal the appearance of a downward jet, which triggers a Kelvin-Helmholtz instability that results in the generation of eddy-like structures with characteristic length scales much larger than the organisms. The measured energy spectrum is consistent with these findings and indicates energy input at large scales, despite the small individual size of the organisms. These results motivate the study of biomixing in the presence of stratification to assess the contribution of migrating zooplankton to local and global ocean dynamics. The laser control methodology developed here enables systematic study of the relevant processes.

Wilhelmus, Monica M.; Dabiri, John O.

2014-10-01

193

Benchmarking global land surface models against the observed mean annual runoff from 150 large basins  

NASA Astrophysics Data System (ADS)

SummaryUsing the observed mean annual runoff for 1986-1995 from 150 large basins globally, we evaluate the performance of the 14 global land surface models (LSMs) and six Budyko-type hydrological models that are forced by the meteorological data from the second phase of the Global Soil Wetness Project (GSWP-2). The results show that both the 14 LSMs and six Budyko-type models can explain 55-70% of the spatial variations of mean annual runoff across the selected 150 basins. However, the 14 LSMs show larger biases in the simulated mean annual runoff than the Budyko-type models. The LSMs biases are caused by errors in forcing data, model structure and model parameterisation. The errors in the precipitation forcing data are found to be the main cause for biases in the simulated mean annual runoffs by the Budyko-types models, and most likely for biases in the 14 global land surface models too. The GSWP-2 precipitation is noticeably overestimated at Northern high-latitudes, which causes large positive biases for the LSMs in simulating mean annual runoff in these regions. The most LSMs show large biases in the regions with low mean annual precipitation. Underestimation of the GSWP-2 precipitation in Amazon and Orinoco basins results in significant underestimation in the simulated mean annual runoff by all LSMs and Budyko-type models for these regions. The LSMs with smaller biases generally show larger baseflow ratio in wet basins than in dry basins while the LSMs with larger biases generally show smaller baseflow ratio in wet basins than in dry basins. This indicates that errors in model structure can result in large biases in the simulated runoff. Several parameter sensitivity experiments for one LSM are carried out to investigate impacts on simulated mean runoff. The result indicates that ±20% changes in five key model parameters have relatively smaller impacts on the simulated mean annual runoff across the 150 basins, compared to errors in model structure.

Zhou, Xinyao; Zhang, Yongqiang; Wang, Yingping; Zhang, Huqiang; Vaze, Jai; Zhang, Lu; Yang, Yonghui; Zhou, Yanchun

2012-11-01

194

Volume imaging lidar observations and large-eddy simulations of convective internal boundary layers  

NASA Astrophysics Data System (ADS)

Volume imaging lidar data collected from a site on the western shore of Lake Michigan during the Lake-Induced Convection Experiment provide new observations of convective internal boundary layers and are used to test large-eddy simulations (LESs). Two-dimensional correlation functions of the aerosol backscattering data on horizontal planes reveal the mean motion, orientation, size, spacing and lifetime of the aerosol structures as a function of altitude and offshore distance. Observations show the flow accelerating as a result of the increase in convective mixing and decrease in surface roughness. Although individual lidar backscatter images show remarkable detail of the eddy structure, the averaged backscatter is very homogeneous and does not indicate a well-defined edge to the internal boundary layer despite the tremendous increase in surface heat and moisture flux over the lake. LESs of January 13 were performed using the University of Wisconsin's nonhydrostatic scalable model. To simulate the horizontal homogeneity of turbulence over the land and the inhomogeneity over the lake, a perturbation recycling method was added to the inflow boundary condition. Optical aerosol scattering was estimated from the model output to enable comparison with the lidar data. The simulated lidar backscattering is used for computing correlation functions that can be compared with those from the observed backscatter data. Comparisons show that the LES (1)tends to have smaller convective structures at the smallest scales simulated, (2)tends to produce more elongated convective structures that are aligned with the mean wind direction, and (3)fails to simulate the apparent organization of convective structures by gravity waves. The absence of strong gravity waves in the simulations is probably caused by the limited depth of the model domain and limitations of the lateral boundary conditions.

Mayor, Shane David

195

VERY LARGE ARRAY OH ZEEMAN OBSERVATIONS OF THE STAR-FORMING REGION S88B  

SciTech Connect

We present observations of the Zeeman effect in OH thermal absorption main lines at 1665 and 1667 MHz taken with the Very Large Array toward the star-forming region S88B. The OH absorption profiles toward this source are complicated, and contain several blended components toward a number of positions. Almost all of the OH absorbing gas is located in the eastern parts of S88B, toward the compact continuum source S88B-2 and the eastern parts of the extended continuum source S88B-1. The ratio of 1665/1667 MHz OH line intensities indicates the gas is likely highly clumped, in agreement with other molecular emission line observations in the literature. S88-B appears to present a similar geometry to the well-known star-forming region M17, in that there is an edge-on eastward progression from ionized to molecular gas. The detected magnetic fields appear to mirror this eastward transition; we detected line-of-sight magnetic fields ranging from 90 to 400 {mu}G, with the lowest values of the field to the southwest of the S88B-1 continuum peak, and the highest values to its northeast. We used the detected fields to assess the importance of the magnetic field in S88B by a number of methods; we calculated the ratio of thermal to magnetic pressures, we calculated the critical field necessary to completely support the cloud against self-gravity and compared it to the observed field, and we calculated the ratio of mass to magnetic flux in terms of the critical value of this parameter. All these methods indicated that the magnetic field in S88B is dynamically significant, and should provide an important source of support against gravity. Moreover, the magnetic energy density is in approximate equipartition with the turbulent energy density, again pointing to the importance of the magnetic field in this region.

Sarma, A. P.; Eftimova, M. [Physics Department, DePaul University, 2219 N. Kenmore Ave., Byrne Hall 211, Chicago, IL 60614 (United States)] [Physics Department, DePaul University, 2219 N. Kenmore Ave., Byrne Hall 211, Chicago, IL 60614 (United States); Brogan, C. L. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)] [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Bourke, T. L. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Troland, T. H., E-mail: asarma@depaul.edu [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States)

2013-04-10

196

Utilizing circular scanning in the CZMIL system  

NASA Astrophysics Data System (ADS)

In pursuit of increased reliability and improved signal levels, we employ a scanning approach that supports the high frequency acquisition requirements of the system while utilizing a large aperture receiver. A continuously rotating circular scanner was developed using direct inductance drives to rotate a Fresnel prism, acting as synchronized transmitter-receiver optical element with a fixed incident angle to the sea surface. Circular scanning introduces challenges in evaluating the system's coverage. By its nature, a circular scanning pattern introduces non-uniformity. Unlike galvo-based scanners roll and pitch compensation is practically impossible for a large mechanism, therefore careful planning is required to ensure continuous coverage under realistic operational conditions. Selection of optimal operation parameters is discussed as well as different ways to evaluate surface coverage in different operation modes.

Fuchs, Eran; Mathur, Abhinav

2010-04-01

197

Circular Fibonacci gratings.  

PubMed

We introduce circular Fibonacci gratings (CFGs) that combine the concept of circular gratings and Fibonacci structures. Theoretical analysis shows that the diffraction pattern of CFGs is composed of fractal distributions of impulse rings. Numerical simulations are performed with two-dimensional fast Fourier transform to reveal the fractal behavior of the diffraction rings. Experimental results are also presented and agree well with the numerical results. The fractal nature of the diffraction field should be of great theoretical interest, and shows potential to be further developed into practical applications, such as in laser measurement with wideband illumination. PMID:22086040

Gao, Nan; Zhang, Yuchao; Xie, Changqing

2011-11-01

198

Circular Dichroism of Atomic Florescence  

NASA Astrophysics Data System (ADS)

In recent years there has been considerable interest in the circular dichrosin (CD) of double photoionization of He and even the CD of single photoionization of an atom (c.f. J. Feagin, Phys. Rev. Lett. 88 043001, 2002). A closely related experiment is to look at spontaneously emitted light from an optically pumped sample of rubidium. Using a double slit experiment, it should be possible to observe the CD generated by the exp(-i m ?) dependance of the atomic wavefunction as the input laser helicity is flipped. We have constructed an appropriate apparatus and obtained interference signals, and are now working to measure their phase to demonstrate CD.

Rosenberry, M. A.; Batelaan, H.; Gay, T. J.

2003-05-01

199

Limits On Large Extra Dimensions Based On Observations Of Neutron Stars With The Fermi-Large Area Teleoscope  

NASA Astrophysics Data System (ADS)

We present limits related to the large extra dimensions (LED) model, from the gamma-ray flux of 6 gamma-ray faint neutron stars, using data from the Fermi Large Area Telescope (Fermi-LAT). We assume that Kaluza-Klein (KK) gravitons as predicted in this model are produced in supernova cores, that they are gravitationally retained as neutron stars are formed, and that their decay could contribute to a gamma-ray flux. Considering between 2 and 7 additional spatial dimensions in the context of the LED model, we develop spectral energy distributions (SEDs) of gamma-rays arising from decays of KK gravitons in the vicinity of neutron stars. The SEDs for each number of extra dimensions, n, and each source, are generated by Monte Carlo simulation. Based on 1 year of data from the Fermi-LAT, 95% C.L. upper limits on the size of extra dimensions R from each source are obtained, as well as 95% C.L. lower limits on the (n+4)-dimensional Planck scale, M_D. We obtain combined 95% C.L. upper limits from all the sources on the extra dimensions size, R (m), of 9.0E-9, 3.7E-11, 2.5E-12, 5.0E-13, 1.7E-13, 8.3E-14 for n = 2, 3,. . . ,7. We also obtain 95% C.L. lower limits on the extra-dimensional effective Planck mass, M_D (TeV) of 230, 15, 2.5, 0.66, 0.24, and 0.11 for n = 2,3,. . . ,7. The limits are more stringent than collider limits, for n < 4, and comparable to LHC results for n = 4. We conclude that if the Planck scale is around a TeV, then for n = 2 or 3, the compactification topology must be more complicated than a torus. For extra dimensions of the same size, n ? 4 are favored from our results.

Berenji, Bijan

2011-09-01

200

Exploring the origin of a large cavity in Abell 1795 using deep Chandra observations  

NASA Astrophysics Data System (ADS)

We examine deep stacked Chandra observations of the galaxy cluster Abell 1795 (over 700 ks) to study in depth a large (34 kpc radius) cavity in the X-ray emission. Curiously, despite the large energy required to form this cavity (4PV = 4 × 1060 erg), there is no obvious counterpart to the cavity on the opposite side of the cluster, which would be expected if it has formed due to jets from the central active galactic nucleus (AGN) inflating bubbles. There is also no radio emission associated with the cavity, and no metal enhancement or filaments between it and the brightest cluster galaxy, which are normally found for bubbles inflated by AGN which have risen from the core. One possibility is that this is an old ghost cavity, and that gas sloshing has dominated the distribution of metals around the core. Projection effects, particularly the long X-ray bright filament to the south-east, may prevent us from seeing the companion bubble on the opposite side of the cluster core. We calculate that such a companion bubble would easily have been able to uplift the gas in the southern filament from the core. Interestingly, it has recently been found that inside the cavity is a highly variable X-ray point source coincident with a small dwarf galaxy. Given the remarkable spatial correlation of this point source and the X-ray cavity, we explore the possibility that an outburst from this dwarf galaxy in the past could have led to the formation of the cavity, but find this to be an unlikely scenario.

Walker, S. A.; Fabian, A. C.; Kosec, P.

2014-12-01

201

A Summary of Large Raindrop Observations from GPM GV Field Campaigns  

NASA Technical Reports Server (NTRS)

NASA's Global Precipitation Measurement Mission (GPM) has conducted as series of Ground Validation (GV) studies to assist algorithm development for the GPM core satellite. Characterizing the drop size distribution (DSD) for different types of precipitation systems is critical in order to accurately estimate precipitation across the majority of the planet. Thus far, GV efforts have sampled DSDs in a variety of precipitation systems from Finland to Oklahoma. This dataset consists of over 33 million raindrops sampled by GPM GV's two-dimensional video disdrometers (2DVD) and includes RSD observations from the LPVEx, MC3E, GCPEx, HyMEx and IFloodS campaigns as well as from GV sites in Huntsville, AL and Wallops Island, VA. This study focuses on the larger end of the raindrop size spectrum, which greatly influences radar reflectivity and has implications for moment estimation. Thus knowledge of the maximum diameter is critical to GPM algorithm development. There are over 24,000 raindrops exceeding 5 mm in diameter contained within this disdrometer dataset. The largest raindrops in the 2DVD dataset (>7-8 mm in diameter) are found within intense convective thunderstorms, and their origins are believed to be hailstones. In stratiform rainfall, large raindrops have also been found to fall from lower and thicker melting layers. The 2DVD dataset will be combined with that collected by dual-polarimetric radar and aircraft particle imaging probes to "follow" the vertical evolution of the DSD tail (i.e., retrace the large drops from the surface to their origins aloft).

Gatlin, Patrick N.; Petersen, Walter; Tokay, Ali; Thurai, Merhala; Bringi, V. N.; Carey, Lawrence; Wingo, Matthew

2013-01-01

202

Observation and analysis of nonlinear vibrational relaxation of large molecules in shock waves  

SciTech Connect

We report the observation of highly nonlinear vibrational relaxation for a number of large molecules in shock waves, together with an attempt at a master-equation modeling of this phenomenon. In all these molecules laser-schlieren measurements show a clear and often well-resolved local maximum in the density gradient, indicating a similar maximum in the rate of energy transfer. This unexpected phenomenon is seen in the relaxation of benzene (C{sub 6}H{sub 6}), cubane (C{sub 8}H{sub 8}), cyclopropane (C{sub 3}H{sub 6}), furan (C{sub 4}H{sub 4}O), norbornadiene (C{sub 7}H{sub 8}), oxirane (C{sub 2}H{sub 4}O), and quadricyclane (C{sub 7}H{sub 8}). It has also been detected in cyclopentadiene (C{sub 5}H{sub 6}) and pyrazine (C{sub 4}N{sub 2}H{sub 4}), as well as CF{sub 3}Br and CF{sub 3}Cl but in these was not well resolved. The phenomenon thus seems nearly ubiquitous; of the ''large'' molecules where relaxation could be resolved, only norbornene (at C{sub 7}H{sub 10} the largest such molecule) exhibits a fully linear relaxation. The gradients are clearly and solely from vibrational relaxation; integrated gradients are in good agreement with thermodynamic calculations of total density change, and near-equilibrium relaxation times in pure cyclopropane and oxirane are fully consistent with overlapping ultrasonic results. It appears we are seeing a delay in the development of series coupling in these experiments. An attempt is made to model the process using a linear master equation with exponential gap probabilities having an {alpha}({approx}<{delta}E>{sub down}) linear in energy. Although this does introduce sufficient nonlinearity through the rate coefficients to produce maxima, these and the overall gradients are consistently too small. It is suggested that inclusion of a true nonlinearity through VV transfer will be needed to explain the observations, and a possible mechanism for this is proposed. (c) 2000 American Institute of Physics.

Kiefer, John H. [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States)] [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States); Buzyna, Leonid L. [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States)] [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States); Dib, Amal [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States)] [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States); Sundaram, Sekhar [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States)] [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60680 (United States)

2000-07-01

203

Observational and Model Studies of Large-Scale Mixing Processes in the Stratosphere  

NASA Technical Reports Server (NTRS)

The following is the final technical report for grant NAGW-3442, 'Observational and Model Studies of Large-Scale Mixing Processes in the Stratosphere'. Research efforts in the first year concentrated on transport and mixing processes in the polar vortices. Three papers on mixing in the Antarctic were published. The first was a numerical modeling study of wavebreaking and mixing and their relationship to the period of observed stratospheric waves (Bowman). The second paper presented evidence from TOMS for wavebreaking in the Antarctic (Bowman and Mangus 1993). The third paper used Lagrangian trajectory calculations from analyzed winds to show that there is very little transport into the Antarctic polar vortex prior to the vortex breakdown (Bowman). Mixing is significantly greater at lower levels. This research helped to confirm theoretical arguments for vortex isolation and data from the Antarctic field experiments that were interpreted as indicating isolation. A Ph.D. student, Steve Dahlberg, used the trajectory approach to investigate mixing and transport in the Arctic. While the Arctic vortex is much more disturbed than the Antarctic, there still appears to be relatively little transport across the vortex boundary at 450 K prior to the vortex breakdown. The primary reason for the absence of an ozone hole in the Arctic is the earlier warming and breakdown of the vortex compared to the Antarctic, not replenishment of ozone by greater transport. Two papers describing these results have appeared (Dahlberg and Bowman; Dahlberg and Bowman). Steve Dahlberg completed his Ph.D. thesis (Dahlberg and Bowman) and is now teaching in the Physics Department at Concordia College. We also prepared an analysis of the QBO in SBUV ozone data (Hollandsworth et al.). A numerical study in collaboration with Dr. Ping Chen investigated mixing by barotropic instability, which is the probable origin of the 4-day wave in the upper stratosphere (Bowman and Chen). The important result from this paper is that even in the presence of growing, unstable waves, the mixing barriers around

Bowman, Kenneth P.

1997-01-01

204

Multiwavelength observation of a large-scale flux rope eruption above a kinked small filament  

NASA Astrophysics Data System (ADS)

We analyzed multiwavelength observations of a western limb flare (C3.9) that occurred in AR NOAA 111465 on 30 April 2012. The high-resolution images recorded by SDO/AIA 304, 1600 Å and Hinode/SOT H? show the activation of a small filament (rising speed ~40 km s-1) associated with a kink instability and the onset of a C-class flare near the southern leg of the filament. The first magnetic reconnection occurred at one of the footpoints of the filament and caused the breaking of its southern leg. The filament shows unwinding motion of the northern leg and apex in counterclockwise direction and failed to erupt. A flux-rope structure (visible only in hot channels, i.e., AIA 131 and 94 Å and Hinode/SXT) appeared along the neutral line during the second magnetic reconnection that occurred above the kinked filament. The formation of the RHESSI hard X-ray source (12-25 keV) above the kinked filament and the simultaneous appearance of the hot 131 Å loops associated with photospheric brightenings (AIA 1700 Å) indicates the particle acceleration along these loops from the top of the filament. In addition, extreme ultraviolet disturbances or waves observed above the filament in 171 Å also show a close association with magnetic reconnection. The flux rope rises slowly (~100 km s-1), which produces a very large twisted structure possibly through reconnection with the surrounding sheared magnetic fields within ~15-20 min, and showed an impulsive acceleration reaching a height of about 80-100 Mm. AIA 171 and SWAP 174 Å images reveal a cool compression front (or coronal mass ejection frontal loop) surrounding the hot flux rope structure. Movies associated with Figs. 2 and 7 are available in electronic form at http://www.aanda.org

Kumar, Pankaj; Cho, Kyung-Suk

2014-12-01

205

Wiimote Experiments: Circular Motion  

NASA Astrophysics Data System (ADS)

The advent of new sensor technologies can provide new ways of exploring fundamental physics. In this paper, we show how a Wiimote, which is a handheld remote controller for the Nintendo Wii video game system with an accelerometer, can be used to study the dynamics of circular motion with a very simple setup such as an old record player or a bicycle wheel.

Kouh, Minjoon; Holz, Danielle; Kawam, Alae; Lamont, Mary

2013-03-01

206

The Right Circular Cone  

NSDL National Science Digital Library

This learning object from Wisc-Online covers the right circular cone, examining the properties and components of the shape. The lesson uses the geometric formulas for finding the volume and surface area of the shape. Practice questions are also included.

Jensen, Douglas; Reed, Allen

2005-01-01

207

The Right Circular Cylinder  

NSDL National Science Digital Library

This learning object from Wisc-Online covers the right circular cylinder, examining the properties and components of the shape. The lesson uses the geometric formulas for finding the volume and surface area of the shape. Practice questions are also included.

Jensen, Douglas; Reed, Allen

2005-01-01

208

How do We Choose, Use and Interpret Data From Large Scale Observing Arrays?  

NASA Astrophysics Data System (ADS)

This is a poster presentation of a "website under construction" that will provide free-ware access to spatial analysis modules for Kalman Filtering, Kriging, Neural Networks, Splines, Empirical Orthogonal Function Analysis, and Spatial Objective Analysis. The website is being designed to aid scientists, educators and students with the analysis of data which is generally sparse and irregularly spaced, for which the geographic locations of the observing points are essential inputs to the analyses. Sections for each of the state-of-the-art methodologies will include: 1) Discussion of the objectives for which it was originally developed; 2) Examples of applications to large data sets; 3) Mathematical foundations; 4) References to relevant scientific and mathematical literature; 5) E-links to software for data analysis, with explanations for its use; 6) E-links to data sets for exercise of the technology. Modular construction will permit use of any of the above technologies, independent of others. This "workshop presentation" invites creative input that can contribute to the utility of the final product, from all viewers/potential users.

Thiebaux, H.

2005-12-01

209

Soft X-ray observations of large-scale coronal active region brightenings  

NASA Technical Reports Server (NTRS)

One hundred fifty-six large-scale enhancements of X-ray emission from solar active regions were studied on full-disk filterheliograms to determine characteristic morphology and expansion rates for heated coronal plasma. The X-ray photographs were compared with H-alpha observations of flares, sudden filament disappearances, sprays, and loop prominence systems (LPS). Eighty-one percent of the X-ray events were correlated with H-alpha filament activity, but only 44% were correlated with reported H-alpha flares. The X-ray enhancements took the form of loops or arcades of loops ranging in length from 60,000 km to 520,000 km and averaging 15,000 km in width. Lifetimes ranged from at least 3 hr to more than 24 hr. The event frequency was approximately 1.4 per day. X-ray loop arcades evolved from sharp-edged clouds in cavities vacated by rising H-alpha filaments. Expansion velocities of the loops were about 50 km/s immediately after excitation and 1-10 km/s several hours later. These long-lived loop arcades are identified with LPS, and it is suggested that the loops outlined magnetic fields which were reconnecting after filament eruptions. Another class of X-ray-enhanced loops stretched outside active regions and accompanied sprays or lateral filament ejections. It is suggested that these loops outlined closed magnetic fields guiding slow-mode shocks from flares and filament eruptions.

Rust, D. M.; Webb, D. F.

1977-01-01

210

Search for Large Extra Dimensions Based on Observations of Neutron Stars with the Fermi-LAT  

SciTech Connect

Large extra dimensions (LED) have been proposed to account for the apparent weakness of gravitation. These theories also indicate that the postulated massive Kaluza-Klein (KK) gravitons may be produced by nucleon-nucleon bremsstrahlung in the course of core collapse of supernovae. Hannestad and Raffelt have predicted energy spectra of gamma ray emission from the decay of KK gravitons trapped by the gravity of the remnant neutron stars (NS). These and other authors have used EGRET data on NS to obtain stringent limits on LED. Fermi-LAT is observing radio pulsar positions obtained from radio and x-ray catalogs. NS with certain characteristics are unlikely emitter of gamma rays, and emit in radio and perhaps x-rays. This talk will focus on the blind analysis we plan to perform, which has been developed using the 1st 2 months of all sky data and Monte Carlo simulations, to obtain limits on LED based on about 1 year of Fermi-LAT data. Preliminary limits from this analysis using these first 2 months of data will be also be discussed.

Berenji, Bijan; /Stanford U., Appl. Phys. Dept. /SLAC

2012-09-19

211

Observations of short large-amplitude magnetic structures at a quasi-parallel shock  

NASA Technical Reports Server (NTRS)

Results of a detailed analysis of short large-amplitude magnetic structures (SLAMS) observed at an encounter of the quasi-parallel blow shock by the AMPTE UKS and IRM satellites are presented. Isolated SLAMS, surrounded by solar wind conditions, and embedded SLAMS, which lie within or form the boundary with regions of significant heating and deceleration, are identified. The duration, polarization, and other characteristics of SLAMS are all consistent with their growth directly out of the ULF wave field, including the common occurrence of an attached whistler as found in ULF shocklets. The plasma rest frame propagation speeds and two-spacecraft time delays for all cases show that the SLAMS attempt to propagate upstream against the oncoming flow, but are convected back downstream. The speeds and delays vary systematically with SLAMS amplitude in the way anticipated from nonlinear wave theory, as do their polarization features. Inter-SLAMS regions and boundary regions with solar wind contain hot deflected ions of lesser density than within the SLAMS.

Schwartz, Steven J.; Burgess, David; Wilkinson, William P.; Kessel, Ramona L.; Dunlop, Malcolm; Luehr, Herman

1992-01-01

212

Evidence for cosmic neutrino background form CMB circular polarization  

E-print Network

The primordial anisotropies of the cosmic microwave background are linearly polarized via Compton-scattering. On the other hand, a primordial degree of circular polarization of the Cosmic Microwave Background is not observationally excluded. In this work, we discuss the generation of the circular polarization of CMB via their scattering on the cosmic neutrino background since the epoch of recombination. We show that photon-neutrino interaction can transform plane polarization into circular polarization through processes $\\gamma+\

Rohoollah Mohammadi

2013-12-08

213

Large Lateral Variations of Seismic Anisotropy Observed along the North South Gravity Lineament in China  

NASA Astrophysics Data System (ADS)

The present-day tectonic setting of China is featured by Indian-Eurasian collision in the west and Pacific subduction in the east. The interaction of the Eurasian, Indian, and Pacific Plates has resulted in a unique topographic contrast between eastern and western China. The two regions are bounded by a ~100 km wide, NNE trending lineament known as the North South Gravity Lineament (NSGL). Motion style of the upper mantle around this region is essential for understanding the evolution of China continent. Seismic waves in an anisotropic media travel at different speeds depending on their propagation and polarization directions. In the upper mantle, it is generally believed that seismic anisotropy is caused by a preferred orientation of olivine crystal. The fast direction is parallel to the maximum shear and maximum extension directions for simple shear and pure shear, respectively, and accordingly relates with the motion direction of the upper mantle. We employed a multi-event stacking method to measure the fast direction (?) and splitting time (?t) beneath NSGL with SKS waveform data recorded at epicentral distances of 90°-130°. A total of 219 regional seismic stations operated by the China Earthquake Administration (CEA) were used in this study. These stations covered the continental scarp that extends from the Great Xing'an Range in the northeast to the eastern edge of the Yunnan-Guizhou (Yungui) plateau in the south. From a total of 100 events, we chose 40 earthquakes with high SNR for analyzing. The measured seismic anisotropy exhibited large variations in both ? and ?t along the strike. The fast direction starts from nearly NS at the NE end of the Great Xing'an Range, changes to almost EW along the Yanshanian Orogenic Belt. It then rotates to NE through the Taihang mountain range, and changes back to EW within the Qinling mountain range. Along the eastern border of the Sichuan basin, the fast direction matches well with the NNE oriented mountain ranges in the region. At the eastern and southeastern corner of the Yungui plateau, we observed a nearly EW fast direction. Although the large variation in seismic anisotropy is difficult to be explained by a single deformation process, our results imply that there should be convection in the big mantle wedge beneath eastern China continent.

Ning, S.; Niu, F.; Tao, K.; Cai, C.; Ning, J.

2011-12-01

214

The Circular Velocity Function of Group Galaxies  

NASA Astrophysics Data System (ADS)

A robust prediction of ?CDM cosmology is the halo circular velocity function (CVF), a dynamical cousin of the halo mass function. The correspondence between theoretical and observed CVFs is uncertain, however: cluster galaxies are reported to exhibit a power-law CVF consistent with N-body simulations, but that of the field is distinctly Schechter-like, flattened compared to ?CDM expectations at circular velocities v c <~ 200 km s–1. Groups offer a powerful probe of the role environment plays in this discrepancy as they bridge the field and clusters. Here, we construct the CVF for a large, mass- and multiplicity-complete sample of group galaxies from the Sloan Digital Sky Survey. Using independent photometric v c estimators, we find no transition from field to ?CDM-shaped CVF above v c = 50 km s–1 as a function of group halo mass. All groups with 12.4 <~ log M halo/M ? <~ 15.1 (Local Group analogs to rich clusters) display similar Schechter-like CVFs marginally suppressed at low v c compared to that of the field. Conversely, some agreement with N-body results emerges for samples saturated with late-type galaxies, with isolated late-types displaying a CVF similar in shape to ?CDM predictions. We conclude that the flattening of the low-v c slope in groups is due to their depressed late-type fractions—environment affecting the CVF only to the extent that it correlates with this quantity—and that previous cluster analyses may suffer from interloper contamination. These results serve as useful benchmarks for cosmological simulations of galaxy formation.

Abramson, Louis E.; Williams, Rik J.; Benson, Andrew J.; Kollmeier, Juna A.; Mulchaey, John S.

2014-09-01

215

FERMI LARGE AREA TELESCOPE OBSERVATIONS OF THE CRAB PULSAR AND NEBULA  

SciTech Connect

We report on gamma-ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris provided by the Nancay and Jodrell Bank radio telescopes shows two main peaks stable in phase with energy. The first gamma-ray peak leads the radio main pulse by (281 +- 12 +- 21) mus, giving new constraints on the production site of non-thermal emission in pulsar magnetospheres. The first uncertainty is due to gamma-ray statistics, and the second arises from the rotation parameters. The improved sensitivity and the unprecedented statistics afforded by the LAT enable precise measurement of the Crab Pulsar spectral parameters: cut-off energy at E{sub c} = (5.8 +- 0.5 +- 1.2) GeV, spectral index of GAMMA = (1.97 +- 0.02 +- 0.06) and integral photon flux above 100 MeV of (2.09 +- 0.03 +- 0.18) x 10{sup -6} cm{sup -2} s{sup -1}. The first errors represent the statistical error on the fit parameters, while the second ones are the systematic uncertainties. Pulsed gamma-ray photons are observed up to approx 20 GeV which precludes emission near the stellar surface, below altitudes of around 4-5 stellar radii in phase intervals encompassing the two main peaks. A detailed phase-resolved spectral analysis is also performed: the hardest emission from the Crab Pulsar comes from the bridge region between the two gamma-ray peaks while the softest comes from the falling edge of the second peak. The spectrum of the nebula in the energy range 100 MeV-300 GeV is well described by the sum of two power laws of indices GAMMA{sub sync} = (3.99 +- 0.12 +- 0.08) and GAMMA{sub IC} = (1.64 +- 0.05 +- 0.07), corresponding to the falling edge of the synchrotron and the rising edge of the inverse Compton (IC) components, respectively. This latter, which links up naturally with the spectral data points of Cherenkov experiments, is well reproduced via IC scattering from standard magnetohydrodynamic nebula models, and does not require any additional radiation mechanism.

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Axelsson, M. [Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden); Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Department of Physics and Astronomy, Rice University, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brigida, M., E-mail: loparco@ba.infn.i, E-mail: mazziotta@ba.infn.i, E-mail: grondin@cenbg.in2p3.f, E-mail: lemoine@cenbg.in2p3.f [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)

2010-01-10

216

Observations on sediment mobility in a large gravel-bed river  

NASA Astrophysics Data System (ADS)

This study investigates sediment mobility in a large gravel-bed river (Tagliamento River, northeastern Italy). Field data were used to identify the morphological effectiveness of a range of flows (floods with recurrence interval < 1 to 3.5 year) and for a detailed analysis of the partial transport condition. The analyses were carried out on three cross sections where a number of areas representative of different morphological units (main and secondary channels, low and high bars, islands) were painted. Grain size of the painted area was measured using a photographic method. Monitoring of bed mobility during the study period supplied new photographs of the painted areas, measurements of size and travel distance of the mobilized particles, and estimate of flow depth after each flood event. Our analyses have shown that with dimensionless shear stress around 0.073 (17 N m - 2), the morphological effect over the painted areas was primarily partial transport; while with stresses > 0.1 (25 N m - 2), the bed experienced full mobility, i.e., all the painted particles were transported or totally buried. Full sediment mobility was observed on lower morphological units (i.e., main and secondary channels) under floods with very high frequency ( RI < 1 y), whereas on the low bars full mobility occurred under floods with a recurrence interval slightly > 1 year. Instead, fine deposition and partial transport conditions were observed on the higher bars even after the largest of the monitored floods ( RI = 3.5 y). The analysis of the partial transport condition relies on more than 3500 measurements of particle travel distance (travel distances range from a few centimetres up to 22 m). The transported particles were generally finer than the painted sediments, and the analysis of the sediment transport ratio revealed that partial transport occurred under equal-mobility conditions for particles finer than 32 mm and under size-selective mobility for coarser fractions. This appears to be corroborated (for D < 32 mm) by the insensitiveness of particle transport distance to particle sizes, even if the exponent (? 1) of the relationship between the dimensionless shear stress and the maximum transported diameter would suggest that all fractions are transported under equal-mobility conditions.

Mao, Luca; Surian, Nicola

2010-01-01

217

a Modelling and Observation Study of Convective Interaction with Large-Scale Dynamics in the Tropics.  

NASA Astrophysics Data System (ADS)

Synoptic and planetary scale waves in the tropical atmosphere are observed to modulate deep moist convection, and theorists have long attempted to explain this interaction. Two of the foremost theories developed, wave-CISK and evaporative wind feedback (EWF), have been previously tested using numerical models in which deep convection is parameterized, but the parameterizations did not directly account for modification of the boundary layer by convective downdrafts of low theta_{e} air. The wave-CISK and EWF instabilities are examined in this study using a two dimensional (x-p), hydrostatic, nonrotational model linearized about a basic state in radiative -convective equilibrium, with a convective parameterization by Emanuel (1991) that incorporates the effects of evaporatively driven unsaturated downdrafts. All wave-CISK modes are stable in this model, but long wavelength EWF modes are unstable. The unsaturated downdrafts are shown to have a major damping effect on both short wave EWF and wave -CISK modes. The model's zonal wavenumber 1 and 2 EWF modes have phase speeds 3-4 times larger than that observed for the Madden and Julian Oscillation (MJO). Conceptual studies of EWF modes have parameterized convection by assuming the atmosphere is in strict quasiequilibrium (SQE), and have obtained more realistic phase speeds for the MJO. In SQE, boundary layer theta_{e } and tropospheric temperature changes remain locked together so that CAPE remains constant. It is shown that at long wavelengths, the Emanuel convective parameterization behaves qualitatively in accordance with SQE, and that the quantitative deviations from SQE are partly responsible for the excessively high phase speeds. The validity of the SQE hypothesis is tested on long time and space scales using 11 years of COADS and MSU data, and on time scales of a day to a month using TOGA-COARE sounding data in conjunction with MSU and SSMI precipitation data. It is shown that on the time and space scales studied, SQE is qualitatively valid in that theta_{eb} and < T> are generally positively correlated. However, changes in theta_ {eb} are too large relative to changes in (T) to maintain constant CAPE as predicted by SQE.

Brown, Randy George

218

Multiple self-controlled case series for large-scale longitudinal observational databases.  

PubMed

Characterization of relationships between time-varying drug exposures and adverse events (AEs) related to health outcomes represents the primary objective in postmarketing drug safety surveillance. Such surveillance increasingly utilizes large-scale longitudinal observational databases (LODs), containing time-stamped patient-level medical information including periods of drug exposure and dates of diagnoses for millions of patients. Statistical methods for LODs must confront computational challenges related to the scale of the data, and must also address confounding and other biases that can undermine efforts to estimate effect sizes. Methods that compare on-drug with off-drug periods within patient offer specific advantages over between patient analysis on both counts. To accomplish these aims, we extend the self-controlled case series (SCCS) for LODs. SCCS implicitly controls for fixed multiplicative baseline covariates since each individual acts as their own control. In addition, only exposed cases are required for the analysis, which is computationally advantageous. The standard SCCS approach is usually used to assess single drugs and therefore estimates marginal associations between individual drugs and particular AEs. Such analyses ignore confounding drugs and interactions and have the potential to give misleading results. In order to avoid these difficulties, we propose a regularized multiple SCCS approach that incorporates potentially thousands or more of time-varying confounders such as other drugs. The approach successfully handles the high dimensionality and can provide a sparse solution via an L? regularizer. We present details of the model and the associated optimization procedure, as well as results of empirical investigations. PMID:24117144

Simpson, Shawn E; Madigan, David; Zorych, Ivan; Schuemie, Martijn J; Ryan, Patrick B; Suchard, Marc A

2013-12-01

219

Large-scale stable interacting dark energy model: Cosmological perturbations and observational constraints  

E-print Network

Dark energy might interact with cold dark matter in a direct, nongravitational way. However, the usual interacting dark energy models (with constant $w$) suffer from some catastrophic difficulties. For example, the $Q\\propto\\rho_{\\rm c}$ model leads to an early-time large-scale instability, and the $Q\\propto\\rho_{\\rm de}$ model gives rise to the future unphysical result for cold dark matter density (in the case of a positive coupling). In order to overcome these fatal flaws, we propose in this paper an interacting dark energy model (with constant $w$) in which the interaction term is carefully designed to realize that $Q\\propto\\rho_{\\rm de}$ at the early times and $Q\\propto\\rho_{\\rm c}$ in the future, simultaneously solving the early-time superhorizon instability and future unphysical $\\rho_{\\rm c}$ problems. The concrete form of the interaction term in this model is $Q=3\\beta H \\frac{\\rho_{\\rm{de}}\\rho_{\\rm{c}}}{\\rho_{\\rm{de}}+\\rho_{\\rm{c}}}$, where $\\beta$ is the dimensionless coupling constant. We show that this model is actually equivalent to the decomposed new generalized Chaplygin gas (NGCG) model, with the relation $\\beta=-\\alpha w$. We calculate the cosmological perturbations in this model in a gauge-invariant way and show that the cosmological perturbations are stable during the whole expansion history provided that $\\beta>0$. Furthermore, we use the Planck data in conjunction with other astrophysical data to place stringent constraints on this model (with eight parameters), and we find that indeed $\\beta>0$ is supported by the joint constraint at more than 1$\\sigma$ level. The excellent theoretical features and the support from observations all indicate that the decomposed NGCG model deserves more attention and further investigation.

Yun-He Li; Xin Zhang

2013-12-22

220

Are large Trojan asteroids salty? An observational, theoretical, and experimental study  

NASA Astrophysics Data System (ADS)

With a total mass similar to the main asteroid belt, the jovian Trojan asteroids are a major feature in the Solar System. Based upon the thermal infrared spectra of the largest Trojans obtained with the Spitzer space telescope, Emery et al. (Emery, J.P., Cruikshank, D.P., van Cleve, J. [2006]. Icarus 182, 496) suggested that the surfaces of these Trojans may consist of fine-grained silicates suspended in a transparent matrix. To explore the transparent matrix hypothesis, we adopted a modified radiative transfer model to fit the Trojan spectra simultaneously both in the near and the thermal infrared regions. Our model shows that the Trojan spectra over a wide wavelength range can be consistently explained by fine grained silicates (1-5 wt.%) and highly absorbing material (e.g. carbon or iron, 2-10 wt.%) suspended in a transparent matrix. The matrix is consistent with a deposit of salt on the surfaces of the large Trojans. However, this consistency is not an actual detection of salt and other alternatives may still be possible. We suggest that early in the Solar System history, short-lived radionuclides heated ice-rich Trojans and caused melting, internal circulation of water and dissolution of soluble materials. Briny water volcanism were facilitated by internal volatiles and a possibly global sill of frozen brine was formed beneath the cold primitive crust. The frozen brine layer was likely to be evacuated by impact erosions and evaporation of the exposed brines eventually left a lag deposit of salt. Over the Solar System’s history, fine dust from comets or impacts contaminated and colored these salty surfaces of the Trojans to produce the spectral properties observed today.

Yang, Bin; Lucey, Paul; Glotch, Timothy

2013-03-01

221

New observations of electromagnetic harmonic ELF emissions in the ionosphere by the DEMETER satellite during large magnetic storms  

E-print Network

satellite during large magnetic storms M. Parrot,1 A. Buzzi,1 O. Santoli´k,2 J. J. Berthelier,3 J. A and on 15 May 2005 during two magnetic storms of lower intensity. They can be observed on consecutive orbits harmonic ELF emissions in the ionosphere by the DEMETER satellite during large magnetic storms, J. Geophys

Santolik, Ondrej

222

Circular Migration and Human Development  

Microsoft Academic Search

This paper explores the human development implications of circular migration — both where it occurs naturally and where governments work to create it. The paper discusses various conceptions and definitions of circular migration, and concludes that circular migration is not intrinsically positive or negative in relation to human development; its impact depends upon the circumstances in which it occurs, the

Kathleen Newland

2009-01-01

223

Circular quantum secret sharing  

E-print Network

A circular quantum secret sharing protocol is proposed, which is useful and efficient when one of the parties of secret sharing is remote to the others who are in adjacent, especially the parties are more than three. We describe the process of this protocol and discuss its security when the quantum information carrying is polarized single photons running circularly. It will be shown that entanglement is not necessary for quantum secret sharing. Moreover, the theoretic efficiency is improved to approach 100% as almost all the instances can be used for generating the private key, and each photon can carry one bit of information without quantum storage. It is straightforwardly to utilize this topological structure to complete quantum secret sharing with multi-level two-particle entanglement in high capacity securely.

Fu-Guo Deng; Hong-Yu Zhou andGui Lu Long

2006-12-03

224

Observations of the Earth's polar cleft at large radial distances with the Hawkeye 1 magnetometer  

Microsoft Academic Search

Based on 364-spacecraft passes through the dayside region, the position of the polar cleft at large redial distances was determined with the magnetometer flown on Hawkeye 1. This data set represents one of the largest to investigate the high-latitude region at large radial distances, making it ideal for the study of the cusp and cleft region. Identification of the cleft

W. M. Farrell; J. A. Van Allen

1990-01-01

225

The anticipated role of the large format camera in future earth observation strategies  

Microsoft Academic Search

The development of the National Aeronautics and Space Administration's Large Format Camera has added a new dimension to remote sensing. Offering inexpensive large area coverage imagery with excellent geometric fidelity, the LFC was successfully flown in late 1984 aboard the Space Shuttle. The success of this initial flight has encouraged scientists to propose that the LFC be included as part

Matthew Heric; Carroll Lucas

1989-01-01

226

Comparison of H-alpha synoptic charts with the large-scale solar magnetic field as observed at Stanford  

NASA Technical Reports Server (NTRS)

Two methods of observing the neutral line of the large-scale photospheric magnetic field are compared: neutral line positions inferred from H-alpha photographs (McIntosh and Nolte, 1975) and observations of the photospheric magnetic field made with low spatial resolution (three minutes) and high sensitivity using the Stanford magnetograph. The comparison is found to be very favorable.

Duvall, T. L., Jr.; Wilcox, J. M.; Svalgaard, L.; Scherrer, P. H.; Mcintosh, P. S.

1977-01-01

227

Detection of large scale electron density irregularities during IPS observations at 103 MHz  

Microsoft Academic Search

Observations of angular displacements in the position of the quasar 3C 298 are reported. The observations were carried out during the period of the quasar's interplanetary scintillation (IPS) using a correlation interferometer. Changes in the apparent position of the source were interpreted with respect to variations in the declination of 3C 298. Some possible physical mechanisms for the observed displacements

S. K. Alurkar; H. O. Vats; R. V. Bhonsle; A. K. Sharma

1985-01-01

228

Circular Rainbow seen from a Hilltop  

Microsoft Academic Search

NOTICING a communication in NATURE (p. 361) regarding the phenomenon of a circular rainbow, I thought it worth while to mention a case which lately came under my observation. Standing on a point of rock just opposite the beautiful falls of Montmorenci, Quebec, I was surprised to see a rainbow in the form of a circle passing through my feet.

W. L. Goodwin

1884-01-01

229

Magnetic Moment Coupling to Circularly Polarized Photons  

E-print Network

Exact stationary solutions of the wave equation are obtained to describe the interaction between magnetic moment of elementary particle and circularly polarized photons. The obtained solutions substantially modify the conventional model of field-matter interaction. It follows from them that magnetic moment couples to photons, and this coupling leads to bound particle-photon states with different energies for different orientations of magnetic moment. As a consequence, the interaction splits particle states differing by directions of total angular momentum. Stationary spin splitting, induced by photons, and concomitant effects can be observed for particles exposed to a laser-generated circularly polarized electromagnetic wave.

O. V. Kibis

2009-01-16

230

Computed Flow around an Oscillating Circular Cylinder  

NASA Astrophysics Data System (ADS)

The oscillation of a circular cylinder in a uniform flow is not only one of the basic subjects of fluid dynamics, but is also a very important problem in fluids engineering. In the present paper, the cross-flow and in-line vibrations of a two-dimensional circular cylinder were studied numerically. Both the forced and free vibrations were examined. Vortex shedding became synchronized with the forced cross-flow vibration at a frequency close to that of the Strouhal number of a stationary cylinder. With forced in-line vibration, vortex shedding began to synchronize with the frequency and also one half that of a circular cylinder at a higher vibration rate. With free vibration, the cross-flow vibration was excited when the natural frequency of the cylinder was near the stationary Strouhal number, and in-line vibration was observed near the natural frequency at around twice the stationary Strouhal number.

Asano, Hiroyoshi; Morishita, Etsuo

231

Can simple population genetic models reconcile partial match frequencies observed in large forensic databases?  

Microsoft Academic Search

A recent study of partial matches in the Arizona offender database of DNA profiles has revealed a large number of nine and\\u000a ten locus matches. I use simple models that incorporate the product rule, population substructure, and relatedness to predict\\u000a the expected number of matches in large databases. I find that there is a relatively narrow window of parameter values

Laurence D. Mueller

2008-01-01

232

Circular polarization for electric fields associated with seismic waves generated by blasting  

NASA Astrophysics Data System (ADS)

In discussion on electric fields associated with seismic waves, the so-called electrokinetic effect is the most popular. In fact it has been extensively studied in both field observations and laboratory experiments. In the meantime, we found a circular polarization of electric field in association with aftershocks of large earthquakes and succeeded in explaining this phenomenon by extending the so-called induction effect, as clearly indicated by Honkura et al. [2009], in which we called the mechanism the seismic dynamo effect. It is circular polarization of electric field that is the essential feature in this mechanism. Such polarization can arise if resonance occurs between the frequency of ground velocity and the cyclotron frequency of a certain kind of ion in the Earth's magnetic field. We have so far found clear circular polarization of electric field for aftershocks of two large earthquakes, whereas we have found linear polarization in the cases of artificial seismic wave caused by blasting. It should be noted that the typical frequency of ground velocity observed for natural earthquakes is lower than that for artificial ones. Therefore, at present, there is a possibility that the difference between circular polarization for natural earthquakes and linear polarization for artificial earthquakes arises from a difference in mechanisms corresponding to respective typical frequencies of seismic wave. If the mechanism proposed by Honkura et al. [2009] is universal, irrespective of the types of seismic wave, it is possible to show further examples of circular polarization of electric field even for artificial earthquakes. Hence, we made simultaneous observations of ground velocity and electric field at some sites near blasting points in Japan. Here we present seven examples of electric filed variations obtained for artificial earthquakes. In some cases, electric fields have shown circular polarization, which is left-circular, implying the motion of ions with positive electric charge and the likely ion is Na+ if we take into account of the cyclotron frequency for the Earth's magnetic field at the observation sites. In a few cases, electric field variations arrived at the observation site earlier than the associated waves, although the precursory time is very short, less than 0.1 second. Nevertheless, this is significant in that the electric field travels faster than the elastic wave in the crust with implications of earlier detection of a seismic event.

Matsushima, M.; Honkura, Y.; Kuriki, M.; Ogawa, Y.

2010-12-01

233

Incoherent scatter observations of the ionospheric response to a large solar flare  

Microsoft Academic Search

Incoherent scatter observations at Millstone Hill were made during the ; importance 3B solar flare which occurred at 15:00 UT on 7 August 1972. ; Measurements were obtained of the electron density profile over the height range ; 125 to 1200 km, together with observations of the electron temperature, ion ; temperature, and vertical drift velocity above 225 km. The

Michael Mendillo; John V. Evans

1974-01-01

234

Signatures for Black Hole production from hadronic observables at the Large Hadron Collider  

E-print Network

The concept of Large Extra Dimensions (LED) provides a way of solving the Hierarchy Problem which concerns the weakness of gravity compared with the strong and electro-weak forces. A consequence of LED is that miniature Black Holes (mini-BHs) may be produced at the Large Hadron Collider in p+p collisions. The present work uses the CHARYBDIS mini-BH generator code to simulate the hadronic signal which might be expected in a mid-rapidity particle tracking detector from the decay of these exotic objects if indeed they are produced. An estimate is also given for Pb+Pb collisions.

Thomas J. Humanic; Benjamin Koch; Horst Stoecker

2006-07-10

235

Tempo and mode of modern bird evolution observed with large-scale taxonomic sampling  

E-print Network

, molecular clock, divergence time, fossil record, cretaceous, tertiary Introduction An accurate evolutionary from the fossil record (Blondel and Mourer-Chauvire´ 1998; Dyke and van Tuinen 2004; Clarke et al. 2005 al. 2002) have suggested gaps in the fossil record as large or larger than the known history of ISSN

Hadly, Elizabeth

236

ALIS (Auroral Large Imaging System) used for optical observations of the meteor impact process  

Microsoft Academic Search

This paper outlines a possibly new use of the Auroral Large Imaging System (ALIS) for studies of differential ablation phenomena in meteor trails. By simultaneous imaging from up to six stations, the altitude distribution of the meteor trails could be triangulated, while some stations simultaneously image the trails in for example the sodium (5893 Å) and calcium (4227 Å) lines.

U. Brändström; B. Gustavsson; A. Steen; Asta Pellinen-Wannberg

2001-01-01

237

Interpreting observed northern hemisphere snow trends with large ensembles of climate simulations  

E-print Network

for Atmospheric Research's Community Earth System Model. Two 40-member ensembles driven by historical radiative for Atmospheric Research's Community Earth System Model (CCSM4), in comparison with observations. Each ensemble

238

Observation of a large optical birefringence effect in a (110) oriented porous silicon layer  

NASA Astrophysics Data System (ADS)

We account the observation of the largest reported birefringence effect in a semi-artificial material. An in-plane birefringence of more than 0.7 was observed at the blue-green optical spectral range in a porous silicon film fabricated by electrochemical etching of a (110) Si wafer. Birefringent films are of interest in a variety of applications including sensing and polarization control.

Hakshur, K.; Ruschin, S.

2014-02-01

239

Detection of large scale electron density irregularities during ips observations at 103 MHz  

Microsoft Academic Search

Angular displacements in the positions of the quasar 3C 298 were observed during its interplanetary scintillation (ips) observations made using a correlation interferometer at 103 MHz at Thaltej near Ahmedabad. These changes in the apparent\\u000a positions of the source could be seen as variations in the declination of 3C 298. Two possibilities which might cause such\\u000a effects are considered; refraction

S K Alurkar; H O Vats; R V Bhonsle; A K Sharma

1985-01-01

240

Simultaneous meteor echo observations by large-aperture VHF and UHF radars  

Microsoft Academic Search

We report simultaneous meteor echo observations using the Arecibo 430- MHz and 46.8-MHz radars. Using identical data-taking and meteor selection criteria, 1868 and 367 meteors were found in the 430-MHz and 46.8-MHz beams, respectively, while 145 were found in both beams during the 7 hours of observation. Of the 367 VHF echoes, there were only 10 trail echoes, while the

Q. H. Zhou; P. Perillat; J. Y. N. Cho; J. D. Mathews

1998-01-01

241

Simple Circular Motion Model  

NSDL National Science Digital Library

This simulation is a simple model of rides like an amusement park Merry-Go-Round. The rotational speed and radial distance are controlled with sliders at the bottom of the applet, while net horizontal force on the riders is monitored in the accompanying graph in terms of g-force experienced by riders. The 3D formatting allows viewing from a variety of vantage points. Students discover how rotational speed and radial distance interact to create a more thrilling ride. Don't miss the page link to "Physiological impact of g-forces". Students will learn that setting the speed and radial distance at the highest points will result in g-forces that exceed space shuttle re-entry and fighter jets at high speed. See Related Materials for an interactive tutorial on circular motion, appropriate for high school and lower-level undergraduate studies. The Simple Circular Motion Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the jar file will run the program if Java is installed.

Gallis, Michael R.

2013-10-07

242

Observation of collisionless shocks in a large current-free laboratory plasma  

NASA Astrophysics Data System (ADS)

AbstractWe report the first measurements of the formation and structure of a magnetized collisionless shock by a laser-driven magnetic piston in a current-free laboratory plasma. This new class of experiments combines a high-energy laser system and a <span class="hlt">large</span> magnetized plasma to transfer energy from a laser plasma plume to the ambient ions through collisionless coupling, until a self-sustained MA˜ 2 magnetosonic shock separates from the piston. The ambient plasma is highly magnetized, current free, and <span class="hlt">large</span> enough (17 m × 0.6 m) to support Alfvén waves. Magnetic field measurements of the structure and evolution of the shock are consistent with two-dimensional hybrid simulations, which show Larmor coupling between the debris and ambient ions and the presence of reflected ions, which provide the dissipation. The measured shock formation time confirms predictions from computational work.</p> <div class="credits"> <p class="dwt_author">Niemann, C.; Gekelman, W.; Constantin, C. G.; Everson, E. T.; Schaeffer, D. B.; Bondarenko, A. S.; Clark, S. E.; Winske, D.; Vincena, S.; Van Compernolle, B.; Pribyl, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">243</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18395844"> <span id="translatedtitle"><span class="hlt">Observation</span> of very <span class="hlt">large</span> transverse momentum jets at the CERN pp collider</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The distribution of total tranverse energy SigmaET over the pseudorapidity interval -1 < eta < 1 and an azimuthal range Deltaphi=300° has been measured in the UA2 experiment at the CERN pp collider (sqrt(s) = 540 GeV) using a highly segmented total absorption caloriter. In the events with very <span class="hlt">large</span> SigmaET (SigmaET>~60 GeV) most of the transverse energy is found</p> <div class="credits"> <p class="dwt_author">M. Banner; Ph. Bloch; F. Bonaudi; K. Borer; M. Borghini; J.-C. Chollet; A. G. Clark; C. Conta; P. Darriulat; L. di Lella; J. Dines-Hansen; P.-A. Dorsaz; L. Fayard; M. Fraternali; D. Froidevaux; J.-M. Gaillard; O. Gildemeister; V. G. Goggi; H. Grote; B. Hahn; H. Hänni; J. R. Hansen; P. Hansen; T. Himel; V. Hungerbühler; P. Jenni; O. Kofoed-Hansen; M. Livan; S. Loucatos; B. Madsen; B. Mansoulié; G. C. Mantovani; L. Mapelli; B. Merkel; M. Mermikides; R. Møllerud; B. Nilsson; C. Onions; G. Parrour; F. Pastore; H. Plothow-Besch; J.-P. Repellin; J. Ringel; A. Rothenberg; A. Roussarie; G. Sauvage; J. Schacher; J. L. Siegrist; F. Stocker; J. Tieger; V. Vercesi; H. H. Williams; H. Zaccone; W. Zeller</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">244</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41156837"> <span id="translatedtitle"><span class="hlt">Observations</span> on sediment mobility in a <span class="hlt">large</span> gravel-bed river</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This study investigates sediment mobility in a <span class="hlt">large</span> gravel-bed river (Tagliamento River, northeastern Italy). Field data were used to identify the morphological effectiveness of a range of flows (floods with recurrence interval <1 to 3.5 year) and for a detailed analysis of the partial transport condition. The analyses were carried out on three cross sections where a number of areas representative</p> <div class="credits"> <p class="dwt_author">Luca Mao; Nicola Surian</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">245</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/03559713918412x2.pdf"> <span id="translatedtitle">Some <span class="hlt">observations</span> on the history of <span class="hlt">large</span> philanthropic foundations in Britain and the United States</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Large</span> philanthropic foundations such as those which first developed in the United States in the late nineteenth and early\\u000a twentieth century had four characteristics: (a) the aim of contributing to the public good; (b) applying science and scientific\\u000a method to human affairs, interpreting science broadly; (c) using great wealth to pursue these purposes; and (d) seeking public\\u000a recognition of their</p> <div class="credits"> <p class="dwt_author">Martin Bulmer</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">246</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/4979159"> <span id="translatedtitle">A <span class="hlt">Large</span>-Scale Study of MySpace: <span class="hlt">Observations</span> and Implications for Online Social Networks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We study the characteristics of <span class="hlt">large</span> online social net- works through an extensive analysis of over 1.9 mil- lion MySpace profiles in an effort to understand who is using these networks and how they are being used. We study MySpace through a comparative study over three different, but related, facets: (i) the sociability of users in MySpace based on relationship,</p> <div class="credits"> <p class="dwt_author">James Caverlee; Steve Webb</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22063946"> <span id="translatedtitle">Placement of the dam for the no. 2 kambaratinskaya HPP by <span class="hlt">large</span>-scale blasting: some <span class="hlt">observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Results of complex instrument <span class="hlt">observations</span> of <span class="hlt">large</span>-scale blasting during construction of the dam for the No. 2 Kambaratinskaya HPP on the Naryn River in the Republic of Kirgizia are analyzed. The purpose of these <span class="hlt">observations</span> was: to determine the actual parameters of the seismic process, evaluate the effect of air and acoustic shock waves, and investigate the kinematics of the surface formed by the blast in its core region within the mass of fractured rocks.</p> <div class="credits"> <p class="dwt_author">Shuifer, M. I.; Argal, E. S. [JSC 'SPII Gidroproekt' (Russian Federation)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42049819"> <span id="translatedtitle">Recent <span class="hlt">large</span> reduction in sulfur dioxide emissions from Chinese power plants <span class="hlt">observed</span> by the Ozone Monitoring Instrument</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite <span class="hlt">observed</span> substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where <span class="hlt">large</span> coal-fired power plants were built during this period. The OMI-<span class="hlt">observed</span> SO2\\/NO2 ratio is consistent with the SO2\\/NOx emissions estimated from a bottom-up approach. In 2008 over the same</p> <div class="credits"> <p class="dwt_author">Qiang Zhang; Nickolay A. Krotkov; David G. Streets; Kebin He; Si-Chee Tsay; James F. Gleason</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014AAS...22411106K"> <span id="translatedtitle"><span class="hlt">Observations</span> and Implications of <span class="hlt">Large</span>-Amplitude LongitudinalOscillations in a Solar Filament</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">On 20 August 2010 an energetic disturbance triggered <span class="hlt">large</span>-amplitude longitudinal oscillations in a <span class="hlt">large</span> fraction of a nearby filament. The triggering mechanism appears to be episodic jets connecting the energetic event with the filament threads. We analyzed this periodic motion to characterize the underlying physics of the oscillation as well as the filament properties. The results support our previous theoretical conclusions that the restoring force of <span class="hlt">large</span>-amplitude longitudinal oscillations is solar gravity, and the damping mechanism is the ongoing accumulation of mass onto the oscillating threads. Based on our previous work, we used the fitted parameters to determine the magnitude and radius of curvature of the dipped magnetic field along the filament, as well as the mass accretion rate onto the filament threads. These derived properties are nearly uniform along the filament, indicating a remarkable degree of homogeneity throughout the filament channel. Moreover, the estimated mass accretion rate implies that the footpoint heating responsible for the thread formation, according to the thermal nonequilibrium model, agrees with previous coronal heating estimates. We also estimated the magnitude of the energy released in the nearby event by studying the dynamic response of the filament threads, and concluded that the initiating event is likely to be a microflare. We will present the results of this investigation and discuss their implications for filament structure and heating. This work was supported by NASA’s H-SR program.</p> <div class="credits"> <p class="dwt_author">Karpen, Judith T.; Luna, Manuel; Knizhnik, Kalman J.; Muglach, Karin; Gilbert, Holly; Kucera, Therese A.; Uritsky, Vadim</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.9148E..0AL"> <span id="translatedtitle">Twelve thousand laser-AO <span class="hlt">observations</span>: first results from the Robo-AO <span class="hlt">large</span> surveys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Robo-AO is the first AO system which can feasibly perform surveys of thousands of targets. The system has been operating in a fully robotic mode on the Palomar 1.5m telescope for almost two years. Robo-AO has completed nearly 12,000 high-angular-resolution <span class="hlt">observations</span> in almost 20 separate science programs including exoplanet characterization, field star binarity, young star binarity and solar system <span class="hlt">observations</span>. We summarize the Robo-AO surveys and the <span class="hlt">observations</span> completed to date. We also describe the data-reduction pipeline we developed for Robo-AO—the first fully-automated AO data-reduction, point-spread-function subtraction and companion-search pipeline.</p> <div class="credits"> <p class="dwt_author">Law, Nicholas M.; Baranec, Christoph; Riddle, Reed L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008ApJ...672..962F"> <span id="translatedtitle">High-Resolution ?=1 mm CARMA <span class="hlt">Observations</span> of <span class="hlt">Large</span> Molecules in Orion-KL</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present high-resolution Combined Array for Research in Millimeter-Wave Astronomy (CARMA) ?=1 mm <span class="hlt">observations</span> of several molecular species toward Orion-KL. These are the highest spatial and spectral resolution 1 mm <span class="hlt">observations</span> of these molecules to date. Our <span class="hlt">observations</span> show that ethyl cyanide [C2H5CN] and vinyl cyanide [C2H3CN] originate from multiple cores near the Orion hot core and IRc7. In addition we show that dimethyl ether [(CH3)2O] and methyl formate [HCOOCH3] originate from IRc5 and IRc6 and that acetone [(CH3)2CO] originates only from areas where both N-bearing and O-bearing species are present.</p> <div class="credits"> <p class="dwt_author">Friedel, D. N.; Snyder, L. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/wl37ppu9kqpxg5cv.pdf"> <span id="translatedtitle">Post-stroke depression: research methodology of a <span class="hlt">large</span> multicentre <span class="hlt">observational</span> study (DESTRO)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The heterogeneity of published data regarding post-stroke depression (PSD) prompted an Italian multicenter <span class="hlt">observational</span> study (DESTRO), which took place in 2000–2003. The investigation involved 53 Italian neurology centers: of these, 50 treat acute patients and 3 provide rehabilitation care; 21 centres are in Northern Italy, 20 are in Central Italy, and 12 are in Southern Italy. The time schedule was</p> <div class="credits"> <p class="dwt_author">V. Toso; C. Gandolfo; S. Paolucci; L. Provinciali; R. Torta; N. Grassivaro</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.9239A"> <span id="translatedtitle">Estimating the impact of satellite <span class="hlt">observations</span> on <span class="hlt">large</span>-scale river flood forecasting</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Floods are one of the costliest natural disasters, posing severe risks to human population. Hydraulic models are able to predict flood characteristics, such as water surface elevations and inundated area, and are being used for forecasting operationally although there are many uncertainties. In this work, the potential value of satellite <span class="hlt">observations</span> to initialize these hydraulic models (and their forecasts correspondingly) is explored. The Ensemble Sensitivity method is adapted to evaluate the impact of potential satellite <span class="hlt">observations</span> on the forecasting of flood characteristics. The estimation of the impact is based on the Local Ensemble Transform Kalman Filter, allowing for the forecast error reductions to be computed without additional model runs. The study area was located in the Ohio River basin, and the model used was the LISFLOOD-FP hydrodynamic model. The experimental design consisted of two configurations of the LISFLOOD-FP model. The first (baseline) simulation represents a calibrated 'best effort' model based on a sub-grid channel structure using <span class="hlt">observations</span> for parameters and boundary conditions, whereas the second (background) simulation consists of estimated parameters and SRTM-based boundary conditions. Results showed that the forecast skill was improved for water heights up to lead times of 11 days, while even partial <span class="hlt">observations</span> of the river contained information for the entire river's water surface profile and allowed forecasting 5 to 7 days ahead. On the other hand, discharge forecasts were not improved as much when assimilating water height <span class="hlt">observations</span> although forecast errors were reduced. Finally, the potential for identifying errors in the model structure and parameterizations via the ensemble sensitivity method is discussed.</p> <div class="credits"> <p class="dwt_author">Andreadis, Konstantinos; Schumann, Guy</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120016756&hterms=stars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstars"> <span id="translatedtitle">Limits on <span class="hlt">Large</span> Extra Dimensions Based on <span class="hlt">Observations</span> of Neutron Stars with the Fermi-LAT</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We present limits for the compactification scale in the theory of <span class="hlt">Large</span> Extra Dimensions (LED) proposed by Arkani-Hamed, Dimopoulos, and Dvali. We use 11 months of data from the Fermi <span class="hlt">Large</span> Area Telescope (Fermi-LAT) to set gamma ray flux limits for 6 gamma-ray faint neutron stars (NS). To set limits on LED we use the model of Hannestad and Raffelt (HR) that calculates the Kaluza-Klein (KK) graviton production in supernova cores and the <span class="hlt">large</span> fraction subsequently gravitationally bound around the resulting NS. The predicted decay of the bound KK gravitons to should contribute to the flux from NSs. Considering 2 to 7 extra dimensions of the same size in the context of the HR model, we use Monte Carlo techniques to calculate the expected differential flux of gamma-rays arising from these KK gravitons, including the effects of the age of the NS, graviton orbit, and absorption of gamma-rays in the magnetosphere of the NS. We compare our Monte Carlo-based differential flux to the experimental differential flux using maximum likelihood techniques to obtain our limits on LED. Our limits are more restrictive than past EGRET-based optimistic limits that do not include these important corrections. Additionally, our limits are more stringent than LHC based limits for 3 or fewer LED, and comparable for 4 LED. We conclude that if the effective Planck scale is around a TeV, then for 2 or 3 LED the compactification topology must be more complicated than a torus.</p> <div class="credits"> <p class="dwt_author">Ferrara, E. C.; Scargle, J. D.; Troja, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/1018182"> <span id="translatedtitle"><span class="hlt">Observable</span> T{sub 7] lepton flavor symmetry at the <span class="hlt">large</span> hadron collider.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">More often than not, models of flavor symmetry rely on the use of nonrenormalizable operators (in the guise of flavons) to accomplish the phenomenologically successful tribimaximal mixing of neutrinos. We show instead how a simple renormalizable two-parameter neutrino mass model of tribimaximal mixing can be constructed with the non-Abelian discrete symmetry T{sub 7} and the gauging of B-L. This is also achieved without the addition of auxiliary symmetries and particles present in almost all other proposals. Most importantly, it is verifiable at the <span class="hlt">Large</span> Hadron Collider.</p> <div class="credits"> <p class="dwt_author">Cao, Q.-H.; Khalil, S.; Ma, E.; Okada, H. (High Energy Physics); (Univ. of Chicago); (British Univ. in Egypt); (Ain Shams Univ.); (Univ. of California at Riverside)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-03-29</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MNRAS.429.2069D"> <span id="translatedtitle">A stacked analysis of brightest cluster galaxies <span class="hlt">observed</span> with the Fermi <span class="hlt">Large</span> Area Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present the results of a search for high-energy ?-ray emission from a <span class="hlt">large</span> sample of galaxy clusters sharing the properties of three existing Fermi <span class="hlt">Large</span> Area Telescope detections (in Perseus, Virgo and A3392), namely a powerful radio source within their brightest cluster galaxy (BCG). From a parent, X-ray flux-limited sample of 863 clusters, we select 114 systems with a core-dominated BCG radio flux above 50/75 mJy (in the National Radio Astronomy Observatory Very <span class="hlt">Large</span> Array Sky Survey and the Sydney University Molonglo Sky Survey, respectively), stacking data from the first 45 months of the Fermi mission in three energy bands, to determine statistical limits on the ?-ray fluxes of the ensemble of candidate sources. For a >300 MeV selection, the distribution of detection significance across the sample is consistent with that across control samples for significances <3?, but has a tail extending to higher values, including three >4? signals which are not associated with previously identified ?-ray emission. Modelling of the data in these fields results in the detection of four non-2FGL Fermi sources, though none of these appear to be unambiguously associated with the BCG candidate. Only one is sufficiently close to be a plausible counterpart (RXC J0132.6-0804) and the remaining three appear to be background active galactic nuclei. A search at energies >3 GeV hints at emission from the BCG in A2055, which hosts a BL Lac object. There is no evidence for a signal in the stacked data, and the upper limit derived on the ?-ray flux of an average radio-bright BCG in each band is at least an order of magnitude more constraining than that calculated for individual objects. F1 GeV/F1.4 GHz for an average BCG in the sample is <15, compared with ?120 for NGC 1275 in Perseus, which might indicate a special case for those objects detected at high energies. The tentative suggestion that point-like beamed emission from member galaxies comprise the dominant bright ?-ray sources in clusters implies searches for evidence of dark matter annihilation or <span class="hlt">large</span>-scale merger shock signatures, for example, need to account for a significant level of contamination from within each cluster that is both highly stochastic and varies significantly over time.</p> <div class="credits"> <p class="dwt_author">Dutson, K. L.; White, R. J.; Edge, A. C.; Hinton, J. A.; Hogan, M. T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://hbr.latmos.ipsl.fr/docs/BrogniezPierrehumbert2006.pdf"> <span id="translatedtitle">Using microwave <span class="hlt">observations</span> to assess <span class="hlt">large</span>-scale control of free tropospheric water vapor in the mid-latitudes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Using microwave <span class="hlt">observations</span> to assess <span class="hlt">large</span>-scale control of free tropospheric water vaporGL026240. 1. Introduction [2] Radiative effects due to changes in atmospheric water vapor of midlatitude water vapor is evaluated through reconstructions of the water vapor field using a Lagrangian</p> <div class="credits"> <p class="dwt_author">Brogniez, Hélène</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8213594"> <span id="translatedtitle"><span class="hlt">Large</span>-Scale Variations of the Interplanetary Magnetic Field: Voyager 1 and 2 <span class="hlt">Observations</span> Between 1-5 au.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary"><span class="hlt">Observations</span> by the Voyager 1 and 2 spacecraft of the interplanetary magnetic field between 1 and 5 AU were used to investigate the <span class="hlt">large</span> scale structure of the IMF in a period of increasing solar activity. The Voyager spacecraft found notable deviations ...</p> <div class="credits"> <p class="dwt_author">L. F. Burlaga, R. P. Lepping, K. W. Behannon, L. W. Klein, F. M. Neubauer</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://kaplan.earth.huji.ac.il/wp-content/uploads/2014/05/Oron-Shai.pdf"> <span id="translatedtitle"><span class="hlt">Observations</span> on Physiology and Symbiosis of the <span class="hlt">Large</span> Benthic Foraminiferan Operculina Ammonoides from the Gulf of Eilat</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary"><span class="hlt">Observations</span> on Physiology and Symbiosis of the <span class="hlt">Large</span> Benthic Foraminiferan Operculina Ammonoides. Their symbiosis, calcification physiology, and ecological response to environmental changes are poorly understood that calcification is increasing in fed individuals. These data suggest that the symbiosis in LBF is quite different</p> <div class="credits"> <p class="dwt_author">Simon, Emmanuel</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010JGRA..11510307Y"> <span id="translatedtitle"><span class="hlt">Large</span> wind shears and stabilities in the mesopause region <span class="hlt">observed</span> by Na wind-temperature lidar at midlatitude</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Unexpected <span class="hlt">large</span> horizontal winds and wind shears in the lower thermosphere have been <span class="hlt">observed</span> by rocket soundings and lidars for decades. From 4 years of the Colorado State University sodium wind-temperature lidar data set (2002-2005 total of ˜1600 nocturnal h), we <span class="hlt">observed</span> an altitude distribution of high wind velocity and wind shears between 80 and 105 km, similar to the results of chemical release experiments. Our lidar data show conclusively that when the <span class="hlt">observed</span> wind shears are plotted as a function of the squared Brunt-Vaisala frequency, N2, they are below the value corresponding to the Richardson number of 1/4, which is a necessary condition of the onset of dynamic instability. This suggests that <span class="hlt">large</span> wind shears can be sustained in the region of high static stability, for example, in the lower thermosphere, where <span class="hlt">large</span> wind shears are often <span class="hlt">observed</span> by rocket sounding. The full-diurnal-cycle lidar data enable the extraction of tidal wave components with periods of 24, 12, 8, and 6 h, therefore allowing us to reveal the strong correlation of 60% between <span class="hlt">large</span> wind shears (>50 m s-1 km-1) and tidal waves. The lidar-measured seasonal variation in N2 and tidal amplitudes in the mesosphere and lower thermosphere are found to be consistent with the difference in altitude distribution of strong wind shears between winter and summer.</p> <div class="credits"> <p class="dwt_author">Yue, Jia; She, Chiao-Yao; Liu, Han-Li</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-10-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_15");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ACPD...1324343H"> <span id="translatedtitle">CARIBIC DOAS <span class="hlt">observations</span> of nitrous acid and formaldehyde in a <span class="hlt">large</span> convective cloud</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) flying laboratory measures once per month the chemical composition at cruise altitude (10...12 km) during 4 consecutive Lufthansa flights. Here we present a case study of enhanced nitrogen oxides (NOx), nitrous acid (HONO), and formaldehyde (HCHO) in a thunderstorm cloud over the Caribbean islands of Guadeloupe in August 2011. Nitrous acid is an important reservoir gas for OH radicals, and only few <span class="hlt">observations</span> of HONO at cruise altitude exist. CARIBIC is designed as a long period atmospheric <span class="hlt">observation</span> system, the actual system has been flying almost monthly since 8 yr now. During this period only very few similar events (one since 2008) were <span class="hlt">observed</span>. Due to multiple scattering the light path inside clouds is enhanced, thereby lowering the detection limit of the DOAS instrument. Under background conditions the detection limits are 46 ppt for HONO, 387 ppt for \\chem{HCHO}, and 100 ppt for NO2 and are roughly three times lower inside the cloud. Based on radiative transfer simulations we estimate the path length to 90{ldots}100 km and the cloud top height to ?15 km. The inferred mixing ratios of HONO, HCHO and NO2 are 37 ppt, 400 ppt and 170 ppt, respectively. Bromine monoxide (BrO) remained below the detection limit of 1 ppt. Because the uplifted air masses originated from the remote marine boundary layer and lightning was <span class="hlt">observed</span> in the area by the World Wide Lightning Location Network several hours prior to the measurement, the NO (?1.5 ppb) enhancement was in all likelihood caused by lightning. The main source for the <span class="hlt">observed</span> HCHO is probably updraught from the boundary layer, because the chemical formation of formaldehyde due to methane oxidation is too weak. Besides HCHO also CH3OOH and isoprene are considered as precursors. The chemical box model CAABA is used to estimate the \\chem{NO} and HCHO source strengths, which are necessary to explain our measurements. For NO a source strength of 8.25 × 109 molec cm-2 s-1 km-1 is found, which corresponds to the lightning activity as <span class="hlt">observed</span> by the World Wide Lightning Location network and a lightning emission of 4.2 × 1025 NO molec/flash. The HCHO updraught is of the order of 121 × 109 molec cm-2 s-1 km-1. Also isoprene and CH3OOH as possible HCHO sources were studied and similar source strengths were found.</p> <div class="credits"> <p class="dwt_author">Heue, K.-P.; Riede, H.; Walter, D.; Brenninkmeijer, C. A. M.; Wagner, T.; Frieß, U.; Platt, U.; Zahn, A.; Stratmann, G.; Ziereis, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014DPS....4641411M"> <span id="translatedtitle">Spacewatch <span class="hlt">Observations</span> of Asteroids and Comets Supporting the <span class="hlt">Large</span>-Scale Surveys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We specialize in followup astrometry of Near-Earth Objects (NEOs) of high priority while they are faint, including recently discovered objects on the MPC's Confirmation Page, objects with potential close encounters with Earth, NEOs for which NEOWISE determined albedos and diameters, targets of radar, potential destinations for spacecraft, and special requests by the MPC or JPL. The present era of Spacewatch <span class="hlt">observations</span> began on 2011 Oct 15 with a new imaging camera on our 1.8-meter telescope. From then, the MPC has been accepting an annual average of 8,492 lines of astrometry of 1,018 different NEOs from Spacewatch, including 177 different PHAs per year. Thus we <span class="hlt">observe</span> half of all such objects that are <span class="hlt">observed</span> by anyone in the same interval. We make twice as many measurements of PHAs while they are fainter than V=22 than the next most productive astrometry group. We have contributed to the removal of half of the objects that were retired from JPL's impact risk list. Per year we <span class="hlt">observe</span> about 35 radar targets, 50 NEOs that were measured by NEOWISE, and 100 potential rendezvous destinations. We also average 400 <span class="hlt">observations</span> of comets per year. Since 2004 we have increased our efficiency by a factor of six in terms of <span class="hlt">observations</span> per unit personnel work year by means of new hardware, software, and the automation of the 0.9-m telescope. Last year we received a grant to upgrade our 0.9-m telescope and develop a public archive of image data dating back to 1990. New grants from the NEOO Program now support our use of telescopes larger than the 1.8-meter of Spacewatch and improvement of the efficiency of the Spacewatch 1.8-m. Support of Spacewatch was/is from JPL subcontract 100319 (2010-2011), NASA/NEOO grants NNG06GJ42G, NNX11AB52G, NNX12AG11G, NNX13AP99G, NNX14AL13G, and NNX14AL14G, the Lunar and Planetary Laboratory, Steward Observatory, the Brinson Foundation of Chicago, IL, the estates of R. S. Vail and R. L. Waland, and other private donors. We are also indebted to the MPC of the IAU for their web services.</p> <div class="credits"> <p class="dwt_author">McMillan, Robert S.; Bressi, Terrence H.; Scotti, James V.; Larsen, Jeffrey A.; Mastaler, Ronald A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19800029897&hterms=ngc+missiles&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dngc%2Bmissiles"> <span id="translatedtitle">VLA <span class="hlt">observations</span> of stellar planetary nebulae. [using Very <span class="hlt">Large</span> Array at National Radio Astronomy Observatory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Coordinates, dimensions, 4885-MHz flux densities, and brightness temperatures of K3-2, NGC 6833, Ps 1, II 5117, Me 2-2, Hb 12, Vy 1-1, and M1-5 are reported. In two other cases, H3-29 and H3-75, confused extended structure was detected in which the nebula could not be identified with certainty. He 2-467, M1-2, and Peterson's H-alpha object in M15 were also included in the <span class="hlt">observations</span> but not detected with an upper limit of less than 10 mJy. The <span class="hlt">observations</span> are compared with some of the previous optical and radio data, such as log S(H-beta). Distances are computed from the present data with standard assumptions. Corresponding linear radii range below 0.1 pc, among the smallest in previous distributions of radius.</p> <div class="credits"> <p class="dwt_author">Johnson, H. M.; Balick, B.; Thompson, A. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/1564929"> <span id="translatedtitle"><span class="hlt">Circularly</span> polarized conical patterns from <span class="hlt">circular</span> microstrip antennas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A method is presented for generating <span class="hlt">circularly</span> polarized conical patterns from <span class="hlt">circular</span> microstrip antennas. These antennas are excited at higher order modes and require different feed arrangements for different mode excitations. It is determined that the peak direction of the conical pattern can be varied over a wide angular range. Modal expansion technique is employed to calculate the radiation patterns</p> <div class="credits"> <p class="dwt_author">J. Huang</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999AIPC..471..649P"> <span id="translatedtitle"><span class="hlt">Large</span>-scale structure and coronal dynamics from joint radio, SOHO/EIT and coronagraph <span class="hlt">observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This study presents joint <span class="hlt">observations</span> of an `halo' coronal mass ejection from the EIT telescope and LASCO coronagraphs on SOHO, from the Nançay Radioheliograph (NRH) and the Zurich ETH radiospectrograph (Phoenix-2). This event includes different manifestations: a coronal wave and a dimming region detected by EIT, a CME showing bright discrete portions above east and west limbs. Radio signatures of all these manifestations are found and the interpretation is briefly discussed.</p> <div class="credits"> <p class="dwt_author">Pick, M.; Maia, D.; Vourlidas, A.; Benz, A. O.; Howard, R.; Thompson, B. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23966315"> <span id="translatedtitle">Satellite <span class="hlt">observed</span> widespread decline in Mongolian grasslands <span class="hlt">largely</span> due to overgrazing.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The Mongolian Steppe is one of the largest remaining grassland ecosystems. Recent studies have reported widespread decline of vegetation across the steppe and about 70% of this ecosystem is now considered degraded. Among the scientific community there has been an active debate about whether the <span class="hlt">observed</span> degradation is related to climate, or over-grazing, or both. Here, we employ a new atmospheric correction and cloud screening algorithm (MAIAC) to investigate trends in satellite <span class="hlt">observed</span> vegetation phenology. We relate these trends to changes in climate and domestic animal populations. A series of harmonic functions is fitted to Moderate Resolution Imaging Spectroradiometer (MODIS) <span class="hlt">observed</span> phenological curves to quantify seasonal and inter-annual changes in vegetation. Our results show a widespread decline (of about 12% on average) in MODIS <span class="hlt">observed</span> normalized difference vegetation index (NDVI) across the country but particularly in the transition zone between grassland and the Gobi desert, where recent decline was as much as 40% below the 2002 mean NDVI. While we found considerable regional differences in the causes of landscape degradation, about 80% of the decline in NDVI could be attributed to increase in livestock. Changes in precipitation were able to explain about 30% of degradation across the country as a whole but up to 50% in areas with denser vegetation cover (P < 0.05). Temperature changes, while significant, played only a minor role (r(2)  = 0.10, P < 0.05). Our results suggest that the cumulative effect of overgrazing is a primary contributor to the degradation of the Mongolian steppe and is at least partially responsible for desertification reported in previous studies. PMID:23966315</p> <div class="credits"> <p class="dwt_author">Hilker, Thomas; Natsagdorj, Enkhjargal; Waring, Richard H; Lyapustin, Alexei; Wang, Yujie</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120009349&hterms=mercury&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmercury"> <span id="translatedtitle">MESSENGER Orbital <span class="hlt">Observations</span> of <span class="hlt">Large</span>-Amplitude Kelvin-Helmholtz Waves at Mercury's Magnetopause</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We present a survey of Kelvi\\ n-Helmholtz (KH) waves at Mercury's magnetopause during MESSENGER's first Mercury year in orb it. The waves were identified on the basis of the well-established sawtooth wave signatures that are associated with non-linear KH vortices at the magnetopause. MESSENGER frequently <span class="hlt">observed</span> such KH waves in the dayside region of the magnetosphere where the magnetosheath flow velocity is still sub -sonic, which implies that instability growth rates at Mercury's magnetopau are much larger than at Earth. We attribute these greater rates to the limited wave energy dissipation in Mercury's highly resistive regolith. The wave amplitude was often on the order of ' 00 nT or more, and the wave periods were - 10- 20 s. A clear dawn-dusk asymmetry is present in the data, in that all of the <span class="hlt">observed</span> wave events occurred in the post-noon and dusk-side sectors of the magnetopause. This asymmetry is like ly related to finite Larmor-radius effects and is in agreement with results from particle-in-cell simulations of the instability. The waves were <span class="hlt">observed</span> almost exclusively during periods when the north-south component of the magnetosheath magnetic field was northward, a pattern similar to that for most terrestrial KH wave events. Accompanying plasma measurements show that the waves were associated with the transport of magnetosheath plasma into the magnetosphere.</p> <div class="credits"> <p class="dwt_author">Sundberg, Torbjorn; Boardsen, Scott A.; Slavin, James A.; Anderson, Brian J.; Korth, Haje; Zurbuchen, Thomas H.; Raines, Jim M.; Solomon, Sean C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110007791&hterms=plants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dplants"> <span id="translatedtitle">Recent <span class="hlt">Large</span> Reduction in Sulfur Dioxide Emissions from Chinese Power Plants <span class="hlt">Observed</span> by the Ozone Monitoring Instrument</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite <span class="hlt">observed</span> substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where <span class="hlt">large</span> coal-fired power plants were built during this period. The OMI-<span class="hlt">observed</span> SO2/NO2 ratio is consistent with the SO2/ NO2, emissions estimated from a bottom-up approach. In 2008 over the same areas, OMI detected little change in NO2, suggesting steady electricity output from the power plants. However, dramatic reductions of S0 2 emissions were <span class="hlt">observed</span> by OMI at the same time. These reductions confirm the effectiveness of the flue-gas desulfurization (FGD) devices in reducing S02 emissions, which likely became operational between 2007 and 2008. This study further demonstrates that the satellite sensors can monitor and characterize anthropogenic emissions from <span class="hlt">large</span> point sources.</p> <div class="credits"> <p class="dwt_author">Li, Can; Zhang, Qiang; Krotkov, Nickolay A.; Streets, David G.; He, Kebin; Tsay, Si-Chee; Gleason, James F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010GeoRL..37.8807L"> <span id="translatedtitle">Recent <span class="hlt">large</span> reduction in sulfur dioxide emissions from Chinese power plants <span class="hlt">observed</span> by the Ozone Monitoring Instrument</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite <span class="hlt">observed</span> substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where <span class="hlt">large</span> coal-fired power plants were built during this period. The OMI-<span class="hlt">observed</span> SO2/NO2 ratio is consistent with the SO2/NOx emissions estimated from a bottom-up approach. In 2008 over the same areas, OMI detected little change in NO2, suggesting steady electricity output from the power plants. However, dramatic reductions of SO2 emissions were <span class="hlt">observed</span> by OMI at the same time. These reductions confirm the effectiveness of the flue-gas desulfurization (FGD) devices in reducing SO2 emissions, which likely became operational between 2007 and 2008. This study further demonstrates that the satellite sensors can monitor and characterize anthropogenic emissions from <span class="hlt">large</span> point sources.</p> <div class="credits"> <p class="dwt_author">Li, Can; Zhang, Qiang; Krotkov, Nickolay A.; Streets, David G.; He, Kebin; Tsay, Si-Chee; Gleason, James F.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JSWSC...4A..03L"> <span id="translatedtitle"><span class="hlt">Observations</span> and modeling of GIC in the Chinese <span class="hlt">large</span>-scale high-voltage power networks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During geomagnetic storms, the geomagnetically induced currents (GIC) cause bias fluxes in transformers, resulting in half-cycle saturation. Severely distorted exciting currents, which contain significant amounts of harmonics, threaten the safe operation of equipment and even the whole power system. In this paper, we compare GIC data measured in transformer neutrals and magnetic recordings in China, and show that the GIC amplitudes can be quite <span class="hlt">large</span> even in mid-low latitude areas. The GIC in the Chinese Northwest 750 kV Power Grid are modeled based on the plane wave assumption. The results show that GIC flowing in some transformers exceed 30 A/phase during strong geomagnetic storms. GIC are thus not only a high-latitude problem but networks in middle and low latitudes can be impacted as well, which needs careful attention.</p> <div class="credits"> <p class="dwt_author">Liu, Chunming; Li, Yunlong; Pirjola, Risto</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2877081"> <span id="translatedtitle"><span class="hlt">Large</span>-Range Movements of Neotropical Orchid Bees <span class="hlt">Observed</span> via Radio Telemetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Neotropical orchid bees (Euglossini) are often cited as classic examples of trapline-foragers with potentially extensive foraging ranges. If long-distance movements are habitual, rare plants in widely scattered locations may benefit from euglossine pollination services. Here we report the first successful use of micro radio telemetry to track the movement of an insect pollinator in a complex and forested environment. Our results indicate that individual male orchid bees (Exaerete frontalis) habitually use <span class="hlt">large</span> rainforest areas (at least 42–115 ha) on a daily basis. Aerial telemetry located individuals up to 5 km away from their core areas, and bees were often stationary, for variable periods, between flights to successive localities. These data suggest a higher degree of site fidelity than what may be expected in a free living male bee, and has implications for our understanding of biological activity patterns and the evolution of forest pollinators. PMID:20520813</p> <div class="credits"> <p class="dwt_author">Wikelski, Martin; Moxley, Jerry; Eaton-Mordas, Alexander; Lopez-Uribe, Margarita M.; Holland, Richard; Moskowitz, David; Roubik, David W.; Kays, Roland</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SoPh..289.4563M"> <span id="translatedtitle">Statistical Analysis of <span class="hlt">Large</span>-Scale EUV Waves <span class="hlt">Observed</span> by STEREO/EUVI</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We statistically analyzed the kinematical evolution and wave pulse characteristics of 60 strong <span class="hlt">large</span>-scale EUV wave events that occurred during January 2007 to February 2011 with the STEREO twin spacecraft. For the start velocity, the arithmetic mean is 312±115 km s-1 (within a range of 100 - 630 km s-1). For the mean (linear) velocity, the arithmetic mean is 254±76 km s-1 (within a range of 130 - 470 km s-1). 52 % of all waves under study show a distinct deceleration during their propagation ( a?-50 m s-2), the other 48 % are consistent with a constant speed within the uncertainties (-50? a?50 m s-2). The start velocity and the acceleration are strongly anticorrelated with c?-0.8, i.e. initially faster events undergo stronger deceleration than slower events. The (smooth) transition between constant propagation for slow events and deceleration in faster events occurs at an EUV wave start-velocity of v?230 km s-1, which corresponds well to the fast-mode speed in the quiet corona. These findings provide strong evidence that the EUV waves under study are indeed <span class="hlt">large</span>-amplitude fast-mode MHD waves. This interpretation is also supported by the correlations obtained between the peak velocity and the peak amplitude, impulsiveness, and build-up time of the disturbance. We obtained the following association rates of EUV wave events with other solar phenomena: 95 % are associated with a coronal mass ejection (CME), 74 % to a solar flare, 15 % to interplanetary type II bursts, and 22 % to coronal type II bursts. These findings are consistent with the interpretation that the associated CMEs are the driving agents of the EUV waves.</p> <div class="credits"> <p class="dwt_author">Muhr, N.; Veronig, A. M.; Kienreich, I. W.; Vršnak, B.; Temmer, M.; Bein, B. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3756262"> <span id="translatedtitle">Implementation and management of a biomedical <span class="hlt">observation</span> dictionary in a <span class="hlt">large</span> healthcare information system</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Objective This study shows the evolution of a biomedical <span class="hlt">observation</span> dictionary within the Assistance Publique Hôpitaux Paris (AP-HP), the largest European university hospital group. The different steps are detailed as follows: the dictionary creation, the mapping to logical <span class="hlt">observation</span> identifier names and codes (LOINC), the integration into a multiterminological management platform and, finally, the implementation in the health information system. Methods AP-HP decided to create a biomedical <span class="hlt">observation</span> dictionary named AnaBio, to map it to LOINC and to maintain the mapping. A management platform based on methods used for knowledge engineering has been put in place. It aims at integrating AnaBio within the health information system and improving both the quality and stability of the dictionary. Results This new management platform is now active in AP-HP. The AnaBio dictionary is shared by 120 laboratories and currently includes 50?000 codes. The mapping implementation to LOINC reaches 40% of the AnaBio entries and uses 26% of LOINC records. The results of our work validate the choice made to develop a local dictionary aligned with LOINC. Discussion and Conclusions This work constitutes a first step towards a wider use of the platform. The next step will support the entire biomedical production chain, from the clinician prescription, through laboratory tests tracking in the laboratory information system to the communication of results and the use for decision support and biomedical research. In addition, the increase in the mapping implementation to LOINC ensures the interoperability allowing communication with other international health institutions. PMID:23635601</p> <div class="credits"> <p class="dwt_author">Vandenbussche, Pierre-Yves; Cormont, Sylvie; Andre, Christophe; Daniel, Christel; Delahousse, Jean; Charlet, Jean; Lepage, Eric</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002EGSGA..27.4431B"> <span id="translatedtitle"><span class="hlt">Large</span>-scale Solar Wind Evolution From Minimum To Maximum: Swan <span class="hlt">Observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Based on extensive modelling we conclude that the latitudinal distribution of helio- spheric Lyman- glow is sensitive to the latitudinal distribution of the slow/fast solar wind, averaged over heliographic longitude. In a plane perpendicular to the interstel- lar gas flow axis, an enhancement of the ionization rate about the solar equator, as <span class="hlt">observed</span> by Ulysses in 1995, results in a decrease of the glow intensity at equato- rial latitudes ("the groove"). The FWHM of the groove is related to FWHM of the ionization rate enhancement by a linear formula, which makes it quite easy to infer the latitudinal extent of the slow solar wind (averaged over heliographic longitude) from appropriate <span class="hlt">observations</span> of the heliospheric Lyman- glow. The depth of the groove depends on width of the ionization bulge width and for the assumed height of the ionization bulge it has maximum for the width of about 60 degrees. According to these results, we interpret the long-term changes of the pattern in time as a result of changes of the latitudinal extent of the slow solar wind, averaged over heliographic longitude. From early June, 1996 (the start of relevant SWAN <span class="hlt">observations</span>) till early December, 1998, the slow solar wind was concentrated practically symmetrically at equatorial latitudes. Then it begun to migrate to higher latitudes, first in the south- ern hemisphere (June 1999), then in the northern (December 1999). In June 2000 it engulfed the whole Sun and continued doing so at least till the most recent SOHO pas- sage through the downwind axis in December 2001, with some transient north-south asymmetries in June 2001.</p> <div class="credits"> <p class="dwt_author">Bzowski, M.; Mäkinen, T.; Summanen, T.; Kyrölä, E.; Quémerais, E.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/19236719"> <span id="translatedtitle"><span class="hlt">Observation</span> of B0?pp¯K*0 with a <span class="hlt">Large</span> K*0 Polarization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We <span class="hlt">observe</span> the decay B0 to p pbar K*0 with a branching fraction of\\u000a(1.18^{+0.29}_{-0.25} (stat.) \\\\pm 0.11 (syst.)) \\\\times 10^{-6}. The statistical\\u000asignificance is 7.2 sigma for the signal in the low ppbar mass region. We study\\u000athe decay dynamics of B0 to p pbar K*0 and compare it with B+ to p pbar K*+.\\u000aThe K*0 meson is</p> <div class="credits"> <p class="dwt_author">J.-H. Chen; M.-Z. Wang; I. Adachi; H. Aihara; K. Arinstein; V. Aulchenko; T. Aushev; A. Bakich; V. Balagura; E. Barberio; A. Bay; I. Bedny; K. Belous; U. Bitenc; A. Bondar; A. Bozek; M. Bra?ko; T. Browder; M.-C. Chang; Y. Chao; A. Chen; K.-F. Chen; W. Chen; B. Cheon; R. Chistov; I.-S. Cho; S.-K. Choi; Y. Choi; J. Dalseno; M. Dash; A. Drutskoy; S. Eidelman; B. Golob; H. Ha; J. Haba; T. Hara; K. Hayasaka; H. Hayashii; M. Hazumi; D. Heffernan; Y. Hoshi; W.-S. Hou; Y. Hsiung; H. Hyun; K. Inami; A. Ishikawa; H. Ishino; R. Itoh; M. Iwasaki; N. Joshi; D. Kah; H. Kaji; P. Kapusta; N. Katayama; T. Kawasaki; H. Kichimi; H. Kim; S. Kim; Y. Kim; K. Kinoshita; P. Krokovny; R. Kumar; C. Kuo; Y.-J. Kwon; J. Lee; M. Lee; S. Lee; T. Lesiak; J. Li; A. Limosani; C. Liu; D. Liventsev; F. Mandl; A. Matyja; S. McOnie; T. Medvedeva; W. Mitaroff; H. Miyake; H. Miyata; Y. Miyazaki; R. Mizuk; E. Nakano; M. Nakao; H. Nakazawa; Z. Natkaniec; S. Nishida; O. Nitoh; S. Ogawa; T. Ohshima; S. Okuno; S. Olsen; H. Ozaki; P. Pakhlov; G. Pakhlova; H. Palka; L. Peak; R. Pestotnik; L. Piilonen; M. Rozanska; H. Sahoo; Y. Sakai; O. Schneider; K. Senyo; M. Sevior; M. Shapkin; C. Shen; H. Shibuya; J.-G. Shiu; J. Singh; A. Somov; S. Stani?; M. Stari?; T. Sumiyoshi; F. Takasaki; M. Tanaka; G. Taylor; Y. Teramoto; I. Tikhomirov; K. Trabelsi; S. Uehara; K. Ueno; T. Uglov; Y. Unno; S. Uno; P. Urquijo; Y. Usov; G. Varner; K. Vervink; S. Villa; A. Vinokurova; C. Wang; P. Wang; X. Wang; Y. Watanabe; R. Wedd; E. Won; H. Yamamoto; Y. Yamashita; C. Zhang; Z. Zhang; V. Zhulanov; A. Zupanc</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/1409.6038v2"> <span id="translatedtitle">Loop Equation Analysis of the <span class="hlt">Circular</span> $ ?$ Ensembles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We construct a hierarchy of loop equations for invariant <span class="hlt">circular</span> ensembles. These are valid for general classes of potentials and for arbitrary inverse temperatures $ {\\rm Re}\\,\\beta>0 $ and number of eigenvalues $ N $. Using matching arguments for the resolvent functions of linear statistics $ f(\\zeta)=(\\zeta+z)/(\\zeta-z) $ in a particular asymptotic regime, the global regime, we systematically develop the corresponding <span class="hlt">large</span> $ N $ expansion and apply this solution scheme to the Dyson <span class="hlt">circular</span> ensemble. Currently we can compute the second resolvent function to ten orders in this expansion and also its general Fourier coefficient or moment $ m_{k} $ to an equivalent length. The leading <span class="hlt">large</span> $ N $, <span class="hlt">large</span> $ k $, $ k/N $ fixed form of the moments can be related to the small wave-number expansion of the structure function in the bulk, scaled Dyson <span class="hlt">circular</span> ensemble, known from earlier work. From the moment expansion we conjecture some exact partial fraction forms for the low $ k $ moments. For all of the forgoing results we have made a comparison with the exactly soluble cases of $ \\beta = 1,2,4 $, general $ N $ and even, positive $ \\beta $, $ N=2,3 $.</p> <div class="credits"> <p class="dwt_author">N. S. Witte; P. J. Forrester</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-21</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19840040528&hterms=gk&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dgk"> <span id="translatedtitle">X-ray <span class="hlt">observations</span> of a <span class="hlt">large</span> sample of cataclysmic variable stars using the Einstein Observatory</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">This paper presents the results of an X-ray survey of 31 known or suspected cataclysmic variables. Eighteen of these close binary systems are detected with inferred luminosities in the 0.1-4.0 keV band of between 10 to the 30th and 10 to the 32nd erg/sec. The majority have relatively hard X-ray spectra (kT greater than 2 keV) irrespective of luminosity state. Of seven dwarf novae <span class="hlt">observed</span> during optical outbursts only U Gem exhibited enhanced ultrasoft X-ray emission (kT of about 10 eV) in addition to weak, hard X-ray emission. Variability of the X-ray flux is <span class="hlt">observed</span> in many of these stars, on time-scales ranging from tens of seconds to hours. The contribution to the flux from extended X-ray emission is investigated for SU UMa and GK Per. Several possibilities for the origin of the hard X-rays are considered.</p> <div class="credits"> <p class="dwt_author">Cordova, F. A.; Mason, K. O.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1745311"> <span id="translatedtitle">A LEKID-based CMB instrument design for <span class="hlt">large</span>-scale <span class="hlt">observations</span> in Greenland</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We present the results of a feasibility study, which examined deployment of a ground-based millimeter-wave polarimeter, tailored for <span class="hlt">observing</span> the cosmic microwave background (CMB), to Isi Station in Greenland. The instrument for this study is based on lumped-element kinetic inductance detectors (LEKIDs) and an F/2.4 catoptric, crossed-Dragone telescope with a 500 mm aperture. The telescope is mounted inside the receiver and cooled to $<\\,4$ K by a closed-cycle $^4$He refrigerator to reduce background loading on the detectors. Linearly polarized signals from the sky are modulated with a metal-mesh half-wave plate that is rotated at the aperture stop of the telescope with a hollow-shaft motor based on a superconducting magnetic bearing. The modular detector array design includes at least 2300 LEKIDs, and it can be configured for spectral bands centered on 150~GHz or greater. Our study considered configurations for <span class="hlt">observing</span> in spectral bands centered on 150, 210 and 267~GHz. The entire polarimeter is mounte...</p> <div class="credits"> <p class="dwt_author">Araujo, D C; Bond, J R; Bradford, K J; Chapman, D; Che, G; Day, P K; Didier, J; Doyle, S; Eriksen, H K; Flanigan, D; Groppi, C E; Hillbrand, S N; Johnson, B R; Jones, G; Limon, M; Miller, A D; Mauskopf, P; McCarrick, H; Mroczkowski, T; Reichborn-Kjennerud, B; Smiley, B; Sobrin, J; Wehus, I K; Zmuidzinas, J</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23399408"> <span id="translatedtitle">Occasional <span class="hlt">large</span> emissions of nitrous oxide and methane <span class="hlt">observed</span> in stormwater biofiltration systems.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Designed, green infrastructures are becoming a customary feature of the urban landscape. Sustainable technologies for stormwater management, and biofilters in particular, are increasingly used to reduce stormwater runoff volumes and peaks as well as improve the water quality of runoff discharged into urban water bodies. Although a lot of research has been devoted to these technologies, their effect in terms of greenhouse gas fluxes in urban areas has not been yet investigated. We present the first study aimed at quantifying greenhouse gas fluxes between the soil of stormwater biofilters and the atmosphere. N2O, CH4, and CO2 were measured periodically over a year in two operational vegetated biofiltration cells at Monash University in Melbourne, Australia. One cell had a saturated zone at the bottom, and compost and hardwood mulch added to the sandy loam filter media. The other cell had no saturated zone and was composed of sandy loam. Similar sedges were planted in both cells. The biofilter soil was a small N2O source and a sink for CH4 for most measurement events, with occasional <span class="hlt">large</span> emissions of both N2O and CH4 under very wet conditions. Average N2O fluxes from the cell with the saturated zone were almost five-fold greater (65.6 ?g N2O-N m(-2) h(-1)) than from the other cell (13.7 ?g N2O-N m(-2) h(-1)), with peaks up to 1100 ?g N2O-N m(-2) h(-1). These N2O fluxes are of similar magnitude to those measured in other urban soils, but with larger peak emissions. The CH4 sink strength of the cell with the saturated zone (-3.8 ?g CH4-C m(-2) h(-1)) was lower than the other cell (-18.3 ?g CH4-C m(-2) h(-1)). Both cells of the biofilter appeared to take up CH4 at similar rates to other urban lawn systems; however, the biofilter cells displayed occasional <span class="hlt">large</span> CH4 emissions following inflow events, which were not seen in other urban systems. CO2 fluxes increased with soil temperature in both cells, and in the cell without the saturated zone CO2 fluxes decreased as soil moisture increased. Other studies of CO2 fluxes from urban soils have found both similar and larger CO2 emissions than those measured in the biofilter. The results of this study suggest that the greenhouse gas footprint of stormwater treatment warrant consideration in the planning and implementation of engineered green infrastructures. PMID:23399408</p> <div class="credits"> <p class="dwt_author">Grover, Samantha P P; Cohan, Amanda; Chan, Hon Sen; Livesley, Stephen J; Beringer, Jason; Daly, Edoardo</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22004414"> <span id="translatedtitle"><span class="hlt">OBSERVATIONS</span> OF ENERGETIC HIGH MAGNETIC FIELD PULSARS WITH THE FERMI <span class="hlt">LARGE</span> AREA TELESCOPE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We report the detection of {gamma}-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119-6127 using data from the Fermi <span class="hlt">Large</span> Area Telescope. The {gamma}-ray light curve of PSR J1119-6127 shows a single, wide peak offset from the radio peak by 0.43 {+-} 0.02 in phase. Spectral analysis suggests a power law of index 1.0 {+-} 0.3{sup +0.4}{sub -0.2} with an energy cutoff at 0.8 {+-} 0.2{sup +2.0}{sub -0.5} GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119-6127 and demonstrate that despite the object's high surface magnetic field-near that of magnetars-the field strength and structure in the {gamma}-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the {gamma}-ray pulsed emission for the magnetically active PSR J1846-0258 in the supernova remnant Kesteven 75 and two other energetic high-B pulsars, PSRs J1718-3718 and J1734-3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.</p> <div class="credits"> <p class="dwt_author">Parent, D.; Abdo, A. A. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Kerr, M.; Den Hartog, P. R.; Romani, R. W.; Watters, K.; Craig, H. A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baring, M. G. [Rice University, Department of Physics and Astronomy, MS-108, P.O. Box 1892, Houston, TX 77251 (United States); DeCesar, M. E.; Harding, A. K. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Espinoza, C. M.; Stappers, B. W.; Weltevrede, P. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, The University of Manchester, M13 9PL (United Kingdom); Gotthelf, E. V.; Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Johnston, S. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, P.O. Box 76, Epping NSW 1710 (Australia); Kaspi, V. M.; Livingstone, M. [Department of Physics, McGill University, Montreal, PQ, H3A 2T8 (Canada); Burgay, M. [INAF-Cagliari Astronomical Observatory, I-09012 Capoterra (Italy); Freire, P. C. C., E-mail: dmnparent@gmail.com, E-mail: kerrm@stanford.edu, E-mail: hartog@stanford.edu [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); and others</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-20</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return 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showDiv("page_16");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1749544"> <span id="translatedtitle">Statistical Analysis of <span class="hlt">Large</span>-scale EUV Waves <span class="hlt">Observed</span> by STEREO/EUVI</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We present a statistical analysis of 60 strong <span class="hlt">large</span>-scale EUV wave events that occurred during January 2007 to February 2011 with the STEREO twin spacecraft regarding their kinematical evolution and wave pulse characteristics. For the start velocity, we obtain for the arithmetic mean $312\\pm115$ km s$^{-1}$ (within a range of 100$-$630 km s$^{-1}$). For the mean (linear) velocity, the arithmetic mean is $254\\pm76$ km s$^{-1}$ (within a range of 130$-$470 km s$^{-1}$). 52 % of all waves under study show a distinct deceleration during their propagation ($a\\leq-50$ m s$^{-2}$), the other 48 % are consistent with a constant speed within the uncertainties ($-50\\leq a\\leq50$ m s$^{-2}$). The start velocity and the acceleration show a strong anticorrelation with $c\\approx-0.8$, \\textit i.e initially faster events undergo stronger deceleration than slower events. The (smooth) transition between constant propagation for slow events and deceleration in faster events occurs at an EUV wave start velocity of $v\\approx230...</p> <div class="credits"> <p class="dwt_author">Muhr, Nicole; Kienreich, Ines Waltraud; Vrsnak, Bojan; Temmer, Manuela; Bein, Bianca Maria</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1029131"> <span id="translatedtitle">Fermi <span class="hlt">Large</span> Area Telescope <span class="hlt">Observations</span> of the Cygnus Loop Supernova Remnant</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present an analysis of the gamma-ray measurements by the <span class="hlt">Large</span> Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope in the region of the supernova remnant (SNR) Cygnus Loop (G74.0-8.5). We detect significant gamma-ray emission associated with the SNR in the energy band 0.2-100 GeV. The gamma-ray spectrum shows a break in the range 2-3 GeV. The gamma-ray luminosity is {approx} 1 x 10{sup 33} erg s{sup -1} between 1-100 GeV, much lower than those of other GeV-emitting SNRs. The morphology is best represented by a ring shape, with inner/outer radii 0{sup o}.7 {+-} 0{sup o}.1 and 1{sup o}.6 {+-} 0{sup o}.1. Given the association among X-ray rims, H{alpha} filaments and gamma-ray emission, we argue that gamma rays originate in interactions between particles accelerated in the SNR and interstellar gas or radiation fields adjacent to the shock regions. The decay of neutral pions produced in nucleon-nucleon interactions between accelerated hadrons and interstellar gas provides a reasonable explanation for the gamma-ray spectrum.</p> <div class="credits"> <p class="dwt_author">Katagiri, H.; /Ibaraki U., Mito; Tibaldo, L.; /INFN, Padua /Padua U. /Paris U., VI-VII; Ballet, J.; /Paris U., VI-VII; Giordano, F.; /Bari U. /Bari Polytechnic /INFN, Bari; Grenier, I.A.; /Paris U., VI-VII; Porter, T.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Roth, M.; /Washington U., Seattle; Tibolla, O.; /Wurzburg U.; Uchiyama, Y.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Yamazaki, R.; /Sagamihara, Aoyama Gakuin U.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-08</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://serc.carleton.edu/NAGTWorkshops/structure04/activities/3866.html"> <span id="translatedtitle">Mentally Visualizing <span class="hlt">Large</span> Geologic Structures from Field <span class="hlt">Observations</span>: A Behavioral Study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">We construct artificial outcrops out of plywood on the Lamont campus that together would form a <span class="hlt">large</span> geologic structure, part of which is eroded or covered by dirt and vegetation. One structure is an elongate basin, and another is an anticline. Participants are expert geoscientists and novice learners. They will be guided by an experimenter around a set of outcrops and take notes while walking around. When they finished walking around the outcrops, they will be asked to choose among an array of scale models of possible geologic structures the one that they think best represents the buried structure. Then they will orient the model so that it is aligned with the actual structure in the real world. They will be asked to "think aloud" while choosing and orienting the model; this process is videotaped so that we can analyze their thought processes and develop strategy-training methods. As individual differences measures, they will also be asked to take standard spatial tests and a questionnaire assessing their learning style (verbal vs. spatial).</p> <div class="credits"> <p class="dwt_author">Kastens, Kim; Ishikawa, Toru</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014IAUS..300..428K"> <span id="translatedtitle"><span class="hlt">Observational</span> Study of <span class="hlt">Large</span> Amplitude Longitudinal Oscillations in a Solar Filament</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">On 20 August 2010 an energetic disturbance triggered damped <span class="hlt">large</span>-amplitude longitudinal (LAL) oscillations in almost an entire filament. In the present work we analyze this periodic motion in the filament to characterize the damping and restoring mechanism of the oscillation. Our method involves placing slits along the axis of the filament at different angles with respect to the spine of the filament, finding the angle at which the oscillation is clearest, and fitting the resulting oscillation pattern to decaying sinusoidal and Bessel functions. These functions represent the equations of motion of a pendulum damped by mass accretion. With this method we determine the period and the decaying time of the oscillation. Our preliminary results support the theory presented by Luna and Karpen (2012) that the restoring force of LAL oscillations is solar gravity in the tubes where the threads oscillate, and the damping mechanism is the ongoing accumulation of mass onto the oscillating threads. Following an earlier paper, we have determined the magnitude and radius of curvature of the dipped magnetic flux tubes hosting a thread along the filament, as well as the mass accretion rate of the filament threads, via the fitted parameters.</p> <div class="credits"> <p class="dwt_author">Knizhnik, Kalman; Luna, Manuel; Muglach, Karin; Gilbert, Holly; Kucera, Therese; Karpen, Judith</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1639894"> <span id="translatedtitle">A <span class="hlt">large</span>-scale stable interacting dark energy model: Cosmological perturbations and <span class="hlt">observational</span> constraints</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Dark energy might interact with cold dark matter in a direct, non-gravitational way. However, the usual interacting dark energy models (with constant $w$) suffer from some catastrophic difficulties. For example, the $Q\\propto\\rho_{\\rm c}$ model leads to an early-time <span class="hlt">large</span>-scale instability, and the $Q\\propto\\rho_{\\rm de}$ model gives rise to the future unphysical result for cold dark matter density (in the case of a positive coupling). In order to overcome these fatal flaws, we propose in this paper an interacting dark energy model (with constant $w$) in which the interaction term is carefully designed to realize that $Q\\propto\\rho_{\\rm de}$ at the early times and $Q\\propto\\rho_{\\rm c}$ in the future, simutaneously solving the early-time super-horizon instability and future unphysical $\\rho_{\\rm c}$ problems. The concrete form of the interaction term in this model is $Q=3\\beta H \\frac{\\rho_{\\rm{de}}\\rho_{\\rm{c}}}{\\rho_{\\rm{de}}+\\rho_{\\rm{c}}}$, where $\\beta$ is the dimensionless coupling constant. We show th...</p> <div class="credits"> <p class="dwt_author">Li, Yun-He</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4216041"> <span id="translatedtitle">Mining Cancer-Specific Disease Comorbidities from a <span class="hlt">Large</span> <span class="hlt">Observational</span> Health Database</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Cancer comorbidities often reflect the complex pathogenesis of cancers and provide valuable clues to discover the underlying genetic mechanisms of cancers. In this study, we systematically mine and analyze cancer-specific comorbidity from the FDA Adverse Event Reporting System. We stratified 3,354,043 patients based on age and gender, and developed a network-based approach to extract comorbidity patterns from each patient group. We compared the comorbidity patterns among different patient groups and investigated the effect of age and gender on cancer comorbidity patterns. The results demonstrated that the comorbidity relationships between cancers and non-cancer diseases <span class="hlt">largely</span> depend on age and gender. A few exceptions are depression, anxiety, and metabolic syndrome, whose comorbidity relationships with cancers are relatively stable among all patients. Literature evidences demonstrate that these stable cancer comorbidities reflect the pathogenesis of cancers. We applied our comorbidity mining approach on colorectal cancer and detected its comorbid associations with metabolic syndrome components, diabetes, and osteoporosis. Our results not only confirmed known cancer comorbidities but also generated novel hypotheses, which can illuminate the common pathophysiology between cancers and their co-occurring diseases. PMID:25392682</p> <div class="credits"> <p class="dwt_author">Chen, Yang; Xu, Rong</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1380960"> <span id="translatedtitle"><span class="hlt">Observations</span> of Energetic High Magnetic Field Pulsars with the Fermi <span class="hlt">Large</span> Area Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We report the detection of gamma-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119-6127 using data from the Fermi <span class="hlt">Large</span> Area Telescope. The gamma-ray light curve of PSR J1119-6127 shows a single, wide peak offset from the radio peak by 0.43 pm 0.02 in phase. Spectral analysis suggests a power law of index 1.0 pm 0.3 with an energy cut-off at 0.8 pm 0.2 GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119-6127 and demonstrate that despite the object's high surface magnetic field---near that of magnetars---the field strength and structure in the gamma-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the \\gam-ray pulsed emission for the magnetically active PSR J1846-0258 in the supernova remnant Kesteven 75 and two other energetic high-B pulsars, PSRs J1718-3718 and J1734-3333. We explore possible explanations for the non-detection of these three objects, ...</p> <div class="credits"> <p class="dwt_author">Parent, D; Hartog, P R Den; Baring, M G; DeCesar, M E; Espinoza, C M; Gotthelf, E V; Harding, A K; Johnston, S; Kaspi, V M; Livingstone, M; Romani, R W; Stappers, B W; Watters, K; Weltevrede, P; Abdo, A A; Burgay, M; Camilo, F; Craig, H A; Freire, P C C; Giordano, F; Guillemot, L; Hobbs, G; Keith, M; Kramer, M; Lyne, A G; Manchester, R N; Noutsos, A; Possenti, A; Smith, D A</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMOS14A..07W"> <span id="translatedtitle">The breakup of <span class="hlt">large</span> tabular icebergs - direct <span class="hlt">observations</span> and theoretical considerations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Peter Wadhams and Till Wagner Dept. of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge. We review the factors governing the stability, dynamics and decay of icebergs and describe areas where current models are inadequate. These include questions such as draft changes in capsizing icebergs; iceberg trajectory modelling; the melt rate of the ice underside and ways of reducing it; and wave-induced flexure and its role in the break-up of tabular icebergs. In July 2012 the authors worked on a very <span class="hlt">large</span> (42 sq km) tabular iceberg in Baffin Bay, which had calved from the Petermann Glacier in NW Greenland. We measured incoming swell spectrum and the iceberg response; also the role of buoyancy forces due to erosion of a waterline wave cut and the creation of an underwater ram. The iceberg broke up while we were on it, allowing an instrumental measurement of the calving event. The experiments were included in the BBC-2 film 'Operation Iceberg' shown on Nov 1 2012 and repeated on Nov 18. We conclude that two processes interacted in the break-up event: increased bending stress due to buoyancy of underwater rams; and direct flexural strain due to incidence of ocean swell. Implications for icebergs in the open sea are estimated.</p> <div class="credits"> <p class="dwt_author">Wadhams, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011ApJ...743..170P"> <span id="translatedtitle"><span class="hlt">Observations</span> of Energetic High Magnetic Field Pulsars with the Fermi <span class="hlt">Large</span> Area Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report the detection of ?-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119-6127 using data from the Fermi <span class="hlt">Large</span> Area Telescope. The ?-ray light curve of PSR J1119-6127 shows a single, wide peak offset from the radio peak by 0.43 ± 0.02 in phase. Spectral analysis suggests a power law of index 1.0 ± 0.3+0.4 - 0.2 with an energy cutoff at 0.8 ± 0.2+2.0 - 0.5 GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119-6127 and demonstrate that despite the object's high surface magnetic field—near that of magnetars—the field strength and structure in the ?-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the ?-ray pulsed emission for the magnetically active PSR J1846-0258 in the supernova remnant Kesteven 75 and two other energetic high-B pulsars, PSRs J1718-3718 and J1734-3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.</p> <div class="credits"> <p class="dwt_author">Parent, D.; Kerr, M.; den Hartog, P. R.; Baring, M. G.; DeCesar, M. E.; Espinoza, C. M.; Gotthelf, E. V.; Harding, A. K.; Johnston, S.; Kaspi, V. M.; Livingstone, M.; Romani, R. W.; Stappers, B. W.; Watters, K.; Weltevrede, P.; Abdo, A. A.; Burgay, M.; Camilo, F.; Craig, H. A.; Freire, P. C. C.; Giordano, F.; Guillemot, L.; Hobbs, G.; Keith, M.; Kramer, M.; Lyne, A. G.; Manchester, R. N.; Noutsos, A.; Possenti, A.; Smith, D. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120008466&hterms=baring+bank+case&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbaring%2Bbank%2Bcase"> <span id="translatedtitle"><span class="hlt">Observations</span> of Energetic High Magnetic Field Pulsars with the Fermi <span class="hlt">Large</span> Area Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We report the detection of gamma-ray pulsations from the high-magnetic-field rotation-powered pulsar PSR J1119.6127 using data from the Fermi <span class="hlt">Large</span> Area Telescope. The gamma-ray light curve of PSR J1119.6127 shows a single, wide peak offset from the radio peak by 0.43 +/- 0.02 in phase. Spectral analysis suggests a power law of index 1.0 +/- 0.3(+0.4 -0.2) with an energy cut-off at 0.8 +/- 0.2(+2.0 -0.5) GeV. The first uncertainty is statistical and the second is systematic. We discuss the emission models of PSR J1119.6127 and demonstrate that despite the object's high surface magnetic field--near that of magnetars -- the field strength and structure in the gamma-ray emitting zone are apparently similar to those of typical young pulsars. Additionally, we present upper limits on the gamma-ray pulsed emission for the magnetically active PSR J1846.0258 in the supernova remnant Kesteven 75 and two other energetic high-Beta pulsars, PSRs J1718.3718 and J1734.3333. We explore possible explanations for the non-detection of these three objects, including peculiarities in their emission geometry.</p> <div class="credits"> <p class="dwt_author">Parent, D.; Kerr, M.; DenHartog, P. R.; Baring, M. G.; DeCesar, M. E.; Espinoza, C. M.; Harding, A. K.; Romani, R. W.; Stappers, B. W.; Watters, K.; Weltevrde, P.; Abdo, A. A.; Craig, H. A.; Kramer, M.; Lyne, A. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3573060"> <span id="translatedtitle">Sleeping Patterns of Afghan Unaccompanied Asylum-Seeking Adolescents: A <span class="hlt">Large</span> <span class="hlt">Observational</span> Study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Unaccompanied asylum-seeking children (UASC) have experienced multiple traumas and are a high-risk group for posttraumatic stress disorder (PTSD). The effects of trauma are known to be associated with sleep problems; indeed sleeping problems are core features of PTSD. However, there has been no systematic research examining the sleep of this high risk group of children. This study presents the first evidence on the sleeping patterns of Afghan UASC living in the UK. A total of 222 male Afghan children, aged 13–18, were interviewed using validated self-report questionnaires measuring sleeping patterns and PTSD. Overall, UASC patterns for bed time and rise time appear acculturated to the country of asylum. Mean UASC sleep onset latency scores were approximately 20 minutes greater compared with normative scores, which may be a reflection of UASC pre-migration and post-migration experiences. As expected, UASC who screened above the clinical cut-off for PTSD reported significantly greater sleep onset latency, increased nightmares, and less total sleep time compared to the non-PTSD group. The results may be of particular interest to clinicians given that, compared to screening for PTSD, screening for sleep problems may be a less culturally disputed form of initial assessment indicating distress in UASC. Similarly, the field of UASC and refugee child interventions is <span class="hlt">largely</span> focused on trauma, yet sleep may provide a novel avenue for equally or more effective treatment. PMID:23457517</p> <div class="credits"> <p class="dwt_author">Bronstein, Israel; Montgomery, Paul</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22043827"> <span id="translatedtitle"><span class="hlt">Observation</span> of abnormally <span class="hlt">large</span> radii of nuclei in excited states in the vicinity of neutron thresholds</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Differential cross sections for inelastic scattering leading to the excitation of some nuclear states situated near neutron-emission thresholds were analyzed. With the aid of a modified diffraction model, abnormally <span class="hlt">large</span> radii were found for the 1/2{sub 1}{sup +} state of the {sup 13}C nucleus at 3.09 MeV, for the first levels of positive-parity rotational bands in the {sup 9}Be (1/2{sup +} level at 1.68 MeV and 5/2{sup +} level at 3.05 MeV) and {sup 11}Be (5/2{sup +} level at 1.78 MeV and 3/2{sup +} level at 3.41 MeV) nuclei, and for the 2{sub 1}{sup +} state of the {sup 14}Be nucleus at 1.54 MeV and 1{sub 1}{sup -} state of the {sup 12}Be nucleus at 2.7 MeV. All of these states possess signatures typical of neutron halos.</p> <div class="credits"> <p class="dwt_author">Ogloblin, A. A., E-mail: ogloblina@bk.ru; Danilov, A. N. [Russian Research Centre Kurchatov Institute (Russian Federation); Belyaeva, T. L. [Universidad Nacional Autonoma de Mexico (UNAM) (Mexico); Demyanova, A. S. [Russian Research Centre Kurchatov Institute (Russian Federation); Goncharov, S. A. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Trzaska, W. [University of Jyvaeskylae (Finland)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-11-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930000938&hterms=large+anticlinal+structures&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dlarge%2Banticlinal%2Bstructures"> <span id="translatedtitle">Melt production in <span class="hlt">large</span>-scale impact events: Planetary <span class="hlt">observations</span> and implications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Differences in scaling relationships for crater formation and the generation of impact melt should lead to a variety of <span class="hlt">observable</span> features and phenomena. These relationships infer that the volume of the transient cavity (and final crater) relative to the volume of impact melt (and the depth to which melting occurs) decreases as the effects of gravity and impact velocity increase. Since planetary gravity and impact velocity are variables in the calculation of cavity and impact-melt volumes, the implications of the model calculation will vary between planetary bodies. Details of the model calculations of impact-melt generation as a function of impact and target physical conditions were provided elsewhere, as were attempts to validate the model through ground-truth data on melt volumes, shock attenuation, and morphology from terrestrial impact craters.</p> <div class="credits"> <p class="dwt_author">Cintala, Mark J.; Grieve, Richard A. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998SSRv...84...83T"> <span id="translatedtitle">The Primordial Helium-4 Abundance from <span class="hlt">Observations</span> of a <span class="hlt">Large</span> Sample of Blue Compact Dwarf Galaxies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We use a sample of 45 low-metallicity H II regions in blue compact dwarf (BCD) galaxies to determine the primordial helium abundance YP with a precision better than 5%. We have carefully investigated the physical effects which may make the He I line intensities deviate from their recombination values such as collisional and fluorescent enhancements, underlying He I stellar absorption and absorption by Galactic interstellar Na I. By extrapolating the Y vs. O/H and Y vs. N/H linear regressions to O/H = N/H = 0, we obtain YP = 0.244+/-0.002 and 0.245+/-0.001, respectively, higher than previous determinations (YP = 0.230 - 0.234). Part of the difference comes from the fact that previous investigators have not taken into account underlying He I stellar absorption, especially in the NW component of the BCD I Zw 18 which, because of its extremely low metallicity plays a key role in the determination of YP. We derive a slope dY/dZ = 2.3+/-1.0, considerably smaller than those derived before. With this smaller slope and taking into account the errors, chemical evolution models with an outflow of well-mixed material can be built for star-forming dwarf galaxies which satisfy all the <span class="hlt">observational</span> constraints. Our YP gives $$\\Omega _bh50^2$$ = 0.058+/-0.007, consistent with the lower limit set by dynamical measurements and X-ray <span class="hlt">observations</span> of clusters of galaxies. It is also consistent, within the framework of standard big bang nucleosynthesis theory, with measurements of primordial 7Li in galactic halo stars and with the D/H abundance measured in absorption systems toward quasars by Burles and Tytler (1997).</p> <div class="credits"> <p class="dwt_author">Thuan, Trinh Xuan; Izotov, Yuri. I.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..16.3465D"> <span id="translatedtitle">Seismic <span class="hlt">observations</span> of <span class="hlt">large</span>-scale deformation at the bottom of fast-moving plates</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a new tomographic model of azimuthal anisotropy in the upper mantle and discuss in details the geodynamical causes of this anisotropy. Our model improves upon DKP2005 seismic model (Debayle et al., 2005) through a larger dataset (expanded by a factor ~ 4) and a new approach which allows us to better extract fundamental and higher mode information. Our results confirm that on average, azimuthal anisotropy is only significant in the uppermost 200-250 km of the upper mantle where it decreases regularly with depth. We do not see a significant difference in the amplitude of anisotropy beneath fast oceanic plates, slow oceanic plates or continents. The anisotropy projected onto the direction of present plate motion shows a very specific relation with the plate velocity; it peaks in the asthenosphere around 150 km depth, it is very weak for plate velocities smaller than 3 cm yr-1, increases significantly between 3 and 5 cm yr-1, and saturates for plate velocities larger than 5 cm yr-1. Plate-scale present-day deformation is remarkably well and uniformly recorded beneath the fastest moving plates (India, Coco, Nazca, Australia, Philippine Sea and Pacific plates). Beneath slower plates, plate-motion parallel anisotropy is only <span class="hlt">observed</span> locally, which suggests that the mantle flow below these plates is not controlled by the lithospheric motion (a minimum plate velocity of around 4 cm yr-1 is necessary for a plate to organize the flow in its underlying asthenosphere). The correlation of oceanic anisotropy with the actual plate motion in the shallow lithosphere is very weak. A better correlation is obtained with the fossil accretion velocity recorded by the gradient of local seafloor age. The transition between frozen-in and active anisotropy occurs across the typical age- isotherm that defines the bottom of the thermal lithosphere around 1100 °C. Under fast continents (mostly under Australia and India), the present day velocity orients also the anisotropy in a depth range around 150-200 km depth which is not deeper than what is <span class="hlt">observed</span> under oceans.</p> <div class="credits"> <p class="dwt_author">Debayle, Eric; Ricard, Yanick</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1950419"> <span id="translatedtitle">Multiwavelength <span class="hlt">observation</span> of a <span class="hlt">large</span>-scale flux rope eruption above kinked mini-filament</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We analyse multiwavelength <span class="hlt">observations</span> of a western limb flare (C3.9) occurred in AR NOAA 111465 on 30 April 2012. The high resolution images recorded by SDO/AIA 304, 1600 \\AA\\ and Hinode/SOT H$\\alpha$ show the activation of a mini-filament (rising speed$\\sim$40 km s$^{-1}$) associated with kink instability and the onset of a C-class flare near the southern leg of the filament. The first magnetic reconnection occurred at one of the footpoints of the filament causing the breaking of its southern leg. The filament shows unwinding motion of the northern leg and apex in the counterclockwise direction and failed to erupt. A flux-rope (visible only in hot channels, i.e., AIA 131 and 94 \\AA\\ channels and Hinode/SXT) structure was appeared along the neutral line during the second magnetic reconnection taking place above the kinked filament. Formation of the RHESSI hard X-ray source (12-25 keV) above the kinked filament and simultaneous appearance of the hot 131 \\AA\\ loops associated with photospheric brightenings (A...</p> <div class="credits"> <p class="dwt_author">Kumar, Pankaj</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014MMTB..tmp..159K"> <span id="translatedtitle"><span class="hlt">Observation</span> of the Mold-Filling Process of a <span class="hlt">Large</span> Hydro-Turbine Guide Vane Casting</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The mold-filling process has a determining effect on the quality of castings, and it has always been a hot but difficult research topic. The authors developed a wireless monitoring system for the mold-filling process of castings based on a contact time method and an <span class="hlt">observation</span> system based on heat-resistant high-speed cameras. By using these two systems, the filling process of a turbine guide vane casting with a stepped gating system was investigated. The filling profile of the casting was recorded, and the filling time of nine typical positions was acquired. These results show that at the beginning, the liquid steel flowed out from the top ingate, which was designed to be the last to fill. The numerical simulation of the filling of the guide vane was performed, and the outflow from the top ingate were predicted. Finally, the gating system of the casting was improved with enlarged sprue. The new design features bigger sprue to ingate ratio; therefore, it could avoid the overflow from the top ingate and realize stable filling.</p> <div class="credits"> <p class="dwt_author">Kang, Jinwu; Long, Haimin; Li, Yongjie; You, Rui; Hao, Xiaokun; Nie, Gang; Wang, Tianjiao; Zhang, Chengchun</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/881248"> <span id="translatedtitle"><span class="hlt">Large</span>-Area Balloon-Borne Polarized Gamma Ray <span class="hlt">Observer</span> (PoGO)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We are developing a new balloon-borne instrument (PoGO), to measure polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth angle distribution of Compton scattering. PoGO is designed to detect 10% polarization in 100mCrab sources in a 6-8 hour <span class="hlt">observation</span> and bring a new dimension to studies on gamma ray emission/transportation mechanism in pulsars, AGNs, black hole binaries, and neutron star surface. The concept is an adaptation to polarization measurements of well-type phoswich counter consisting of a fast plastic scintillator (the detection part), a slow plastic scintillator (the active collimator) and a BGO scintillator (the bottom anti-counter). PoGO consists of close-packed array of 217 hexagonal well-type phoswich counters and has a narrow field-of-view ({approx} 5 deg{sup 2}) to reduce possible source confusion. A prototype instrument has been tested in the polarized soft gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory (KEK). On the results, the polarization dependence of EGS4 has been validated and that of Geant4 has been corrected.</p> <div class="credits"> <p class="dwt_author">Andersson, V.; Chen, P.; Kamae, T.; Madejski, G.; Mizuno, T.; Ng, J.; Tajima, H.; Thurston, T.; /SLAC; Bogaert, G.; /Ecole Polytechnique; Fukazawa, Y.; /Hiroshima U.; Saito,; Takahashi, T.; /Sagamihara, Inst. Space Astron. Sci.; Barbier, L.; Bloser, P.; Harding, A.; Hunter, S.; Krizmanic, J.; Mitchell, J.; Streitmatter, R.; Fernholz, R.; Groth, E.; /NASA, Goddard /Princeton U. /Royal Inst. Tech., Kista /Stockholm U. /Tokyo Inst. Tech. /Yamagata U.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-06-30</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1748820"> <span id="translatedtitle">Swift Ultraviolet <span class="hlt">Observations</span> of Supernova 2014J in M82: <span class="hlt">Large</span> Extinction from Interstellar Dust</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We present optical and ultraviolet (UV) photometry and spectra of the very nearby and highly reddened supernova (SN) 2014J in M82 obtained with the Swift Ultra-Violet/Optical Telescope (UVOT). Comparison of the UVOT grism spectra of SN~2014J with Hubble Space Telescope <span class="hlt">observations</span> of SN2011fe or UVOT grism spectra of SN~2012fr are consistent with an extinction law with a low value of R_V~1.4. The high reddening causes the detected photon distribution in the broadband UV filters to have a much longer effective wavelength than for an unreddened SN. The light curve evolution is consistent with this shift and does not show a flattening due to photons being scattered back into the line of sight. The light curve shapes and color evolution are inconsistent with a contribution scattered into the line of sight by circumstellar dust. We conclude that most or all of the high reddening must come from interstellar dust. We show that even for a single dust composition, there is not a unique reddening law caused by circums...</p> <div class="credits"> <p class="dwt_author">Brown, Peter J; Wang, Lifan; Breeveld, Alice; de Pasquale, Massimiliano; Hartmann, Dieter H; Krisciunas, Kevin; Kuin, N P M; Milne, Peter A; Page, Mat; Siegel, Michael</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22043558"> <span id="translatedtitle"><span class="hlt">Observation</span> of electron plasma waves inside <span class="hlt">large</span> amplitude electromagnetic pulses in a temporally growing plasma</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary"><span class="hlt">Observation</span> of electron plasma waves excited inside high power ({approx}10 kW) short pulse ({approx}20 {mu}s) electromagnetic (em) waves interacting with a gaseous medium (argon) in the pressure range 0.2-2.5 mTorr is reported. The waves have long wavelength ({approx}13 cm) and get damped at time scales slower ({approx}3 {mu}s) than the plasma period (0.1-0.3 {mu}s), the energy conveyed to the medium lead to intense ionization (ion density n{sub i} {approx} 10{sup 11} cm{sup -3} and electron temperature T{sub e} {approx} 6-8 eV) and rapid growth of the plasma ({approx}10{sup 5} s{sup -1}) beyond the waves. Time frequency analysis of the generated oscillations indicate the presence of two principal frequencies centered around 3.8 MHz and 13.0 MHz with a spread {Delta}f {approx} 4 MHz, representing primarily two population of electrons in the plasma wave. The experimental results are in reasonable agreement with a model that considers spatiotemporal forces of the em wave on the medium, space charges and diffusion.</p> <div class="credits"> <p class="dwt_author">Pandey, Shail; Bhattacharjee, Sudeep; Sahu, Debaprasad [Department of Physics, Indian Institute of Technology, Kanpur-208016 (India)</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-15</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_17");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.A12B..03Y"> <span id="translatedtitle">Suomi-NPP OMPS <span class="hlt">Observations</span> of <span class="hlt">Large</span>-Scale Air Pollution Events over China</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Severe smog episodes over China in January 2013 received worldwide attention. This air pollution is distinguished by high concentrations of gaseous pollutants (SO2 and NO2) and heavy loadings of fine particulate matter. To characterize these episodes, we employed the Ozone Mapping and Profiler Suite, Nadir Mapper (OMPS NM), a hyper-spectral UV spectrometer flying on the Suomi National Polar-orbiting Partnership (SNPP) spacecraft since October 2011. We developed an advanced algorithm to detect and quantify SO2 and NO2 in the lower atmosphere, and applied it to the OMPS NM <span class="hlt">observations</span>. Here we report retrievals of SO2 and NO2, as well as UV aerosol index data for these pollution events. The columns of SO2 and NO2 and the areas covered by high pollutant concentrations are quantified; the results reveal for the first time the full extent (an area of ~10^6 km^2 containing up to 60 kt of SO2) of these episodes.</p> <div class="credits"> <p class="dwt_author">Yang, K.; Dickerson, R. R.; Carn, S. A.; Wang, J.; Ge, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110023494&hterms=rejecting+parents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Drejecting%2Bparents"> <span id="translatedtitle">Fermi <span class="hlt">Large</span> Area Telescope <span class="hlt">Observations</span> of the Supernova Remnant GS.7-0.1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the <span class="hlt">Large</span> Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship among G8.7-0.l and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.l and a lesser part located outside the western boundary of G8.7-0.l. The region of the gamma-ray emission overlaps spatially-connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 +/- 0.6 (stat) +/- 1.2 (sys) GeV, and photon indices of 2.10 +/- 0.06 (stat) +/- 0.10 (sys) below the break and 2.70 +/- 0.12 (stat) +/- 0.l4 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of 1IoS produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in the GeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.</p> <div class="credits"> <p class="dwt_author">Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Ferrara, E. C.; Harding, A. K.; Hays, E.; Moiseev, A. A.; Troja, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120016522&hterms=rejecting+parents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Drejecting%2Bparents"> <span id="translatedtitle">Fermi <span class="hlt">Large</span> Area Telescope <span class="hlt">Observations</span> of the Supernova Remnant GS.7-0.1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the <span class="hlt">Large</span> Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope. An investigation of the relationship among G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially-connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 +/- 0.6 (stat) +/- 1.2 (sys) GeV, and photon indices of2.10 +/- 0.06 (stat) +/- 0.10 (sys) below the break and 2.70 +/- 0.12 (stat) +/- 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission ofG8.7-0.1, and the molecular clouds, the decay of pions produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS Jl804-2l6 and that the spectrum in the Ge V band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV-spectrum originates from the interaction of particles accelerated in G8.7-0.l with molecular clouds, and we constrain the diffusion coefficient of the particles.</p> <div class="credits"> <p class="dwt_author">Ferrara, E. C.; Hays, E.; Troja, E.; Moiseev, A. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1050861"> <span id="translatedtitle">Fermi <span class="hlt">Large</span> Area Telescope <span class="hlt">Observations</span> of the Supernova Remnant G8.7-0.1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the <span class="hlt">Large</span> Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 {+-} 0.6 (stat) {+-} 1.2 (sys) GeV, and photon indices of 2.10 {+-} 0.06 (stat) {+-} 0.10 (sys) below the break and 2.70 {+-} 0.12 (stat) {+-} 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of p0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally explains the GeV gamma-ray spectrum. We also find that the GeV morphology is not well represented by the TeV emission from HESS J1804-216 and that the spectrum in the GeV band is not consistent with the extrapolation of the TeV gamma-ray spectrum. The spectral index of the TeV emission is consistent with the particle spectral index predicted by a theory that assumes energy-dependent diffusion of particles accelerated in an SNR. We discuss the possibility that the TeV spectrum originates from the interaction of particles accelerated in G8.7-0.1 with molecular clouds, and we constrain the diffusion coefficient of the particles.</p> <div class="credits"> <p class="dwt_author">Ajello, M.; Allafort, A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Baldini, L.; /INFN, Pisa; Ballet, J.; /AIM, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bellazzini, R.; /INFN, Pisa; Berenji, B.; Blandford, R.D.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Bregeon, J.; /INFN, Pisa; Brigida, M.; /Bari Polytechnic /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Buehler, R.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Buson, S.; /INFN, Padua /Padua U.; Caliandro, G.A.; /CSIC, Catalunya; Cameron, R.A.; /Stanford U., HEPL /KIPAC, Menlo Park /SLAC; Caraveo, P.A.; /IASF, Milan /AIM, Saclay /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Unlisted, US /Naval Research Lab, Wash., D.C. /Perugia U. /ASDC, Frascati /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Montpellier U. /ASDC, Frascati /Udine U. /INFN, Trieste /Bari Polytechnic /INFN, Bari /Naval Research Lab, Wash., D.C. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Bari Polytechnic /INFN, Bari /Ecole Polytechnique /NASA, Goddard /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Udine U. /INFN, Trieste /Trieste Observ. /Hiroshima U. /Nagoya U. /Bari Polytechnic /INFN, Bari /INFN, Bari /ASDC, Frascati /INFN, Perugia /Perugia U. /Bari Polytechnic /INFN, Bari /ASDC, Frascati /Bari Polytechnic /INFN, Bari /Bologna Observ. /Stanford U., HEPL /KIPAC, Menlo Park /SLAC /Naval Research Lab, Wash., D.C. /Alabama U., Huntsville /CSIC, Catalunya /Hiroshima U. /NASA, Goddard /Hiroshima U.; /more authors..</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-09-14</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6326316"> <span id="translatedtitle">Report on the analysis of the <span class="hlt">large</span> propagation velocities <span class="hlt">observed</span> in the full-length SSC (Superconducting Super Collider) dipoles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Very <span class="hlt">large</span> propagation velocities have been <span class="hlt">observed</span> in the Superconducting Super Collider (SSC) 17-m dipoles: from 75 m/s to 225 m/s, depending on the current. These velocities are much larger than those predicted by the classical conduction theory of normal zone propagation. A plausible explanation for such rapid propagation is hydrodynamic mechanism called thermal hydraulic quenchback (THQ) that has been proposed by Luongo et al. This report supplies an approximate analytic theory of THQ, which is used to analyze the data taken on the SSC 17-m dipoles. It is concluded that THQ in the helium in the interstices of the cable can explain the <span class="hlt">large</span> propagation velocities <span class="hlt">observed</span>. Additional experiments are proposed to test the hydrodynamic explanation. 17 refs., 5 figs.</p> <div class="credits"> <p class="dwt_author">Dresner, L.; Lue, J.W.; Lubell, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009PhRvD..80l2004A"> <span id="translatedtitle">Fermi <span class="hlt">large</span> area telescope <span class="hlt">observations</span> of the cosmic-ray induced ?-ray emission of the Earth's atmosphere</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report on measurements of the cosmic-ray induced ?-ray emission of Earth’s atmosphere by the <span class="hlt">Large</span> Area Telescope on board the Fermi Gamma-ray Space Telescope. The <span class="hlt">Large</span> Area Telescope has <span class="hlt">observed</span> the Earth during its commissioning phase and with a dedicated Earth limb following <span class="hlt">observation</span> in September 2008. These measurements yielded ˜6.4×106 photons with energies >100MeV and ˜250 hours total live time for the highest quality data selection. This allows the study of the spatial and spectral distributions of these photons with unprecedented detail. The spectrum of the emission—often referred to as Earth albedo gamma-ray emission—has a power-law shape up to 500 GeV with spectral index ?=2.79±0.06.</p> <div class="credits"> <p class="dwt_author">Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Burnett, T. H.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; de Palma, F.; Digel, S. W.; Do Couto E Silva, E.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Fortin, P.; Frailis, M.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M.-H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, T. J.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kerr, M.; Knödlseder, J.; Kuss, M.; Lande, J.; Latronico, L.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Rochester, L. S.; Rodriguez, A. Y.; Roth, M.; Sadrozinski, H. F.-W.; Sander, A.; Saz Parkinson, P. M.; Sgrò, C.; Share, G. H.; Siskind, E. J.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Strickman, M. S.; Suson, D. J.; Takahashi, H.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Usher, T. L.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Ylinen, T.; Ziegler, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55164721"> <span id="translatedtitle">Gamma-Ray <span class="hlt">Observations</span> of the Supernova Remnant RX J0852.0-4622 with the Fermi <span class="hlt">Large</span> Area Telescope</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report on gamma-ray <span class="hlt">observations</span> of the supernova remnant (SNR) RX J0852.0-4622 with the <span class="hlt">Large</span> Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. In the Fermi-LAT data, we find a spatially extended source at the location of the SNR. The extension is consistent with the SNR size seen in other wavelengths such as X-rays and TeV gamma rays,</p> <div class="credits"> <p class="dwt_author">T. Tanaka; A. Allafort; J. Ballet; S. Funk; F. Giordano; J. Hewitt; M. Lemoine-Goumard; H. Tajima; O. Tibolla; Y. Uchiyama</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/12289626"> <span id="translatedtitle"><span class="hlt">Circular</span> on family planning, 1988.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">This Hubei, China, <span class="hlt">Circular</span>, issued near the end of 1988, provides the following: "The population growth situation in our country is grim. Since 1986, the natural population growth rate has risen continuously. To draw the prompt attention of the whole party and the entire people to the issue of our population, all localities must seriously unfold the activities of publicizing family planning (FP) this winter and next spring, in coordination with education in current affairs. It is necessary to publicize FP in an all-around way and with accuracy, and the activities of publicizing must be carried out effectively in a solid and deep-going way. In the rural areas, stress must be placed on areas where FP work is not carried out well and where there is a prevailing tendency toward early marriage, early child-bearing, and extra-budgetary births. In cities, publicity and education must be conducted especially among the transient population, individual households, and jobless households. During the period of publicity, <span class="hlt">large</span>-scale street-corner publicity activities must be carried out in cities and towns so as to create strong public opinion and to combine the endeavor to publicize current affairs and policies with the effort to popularize knowledge about contraception and birth-control, to execute measures of contraception and birth control, and to establish FP associations in the countryside." PMID:12289626</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25281217"> <span id="translatedtitle">Short intronic repeat sequences facilitate <span class="hlt">circular</span> RNA production.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Recent deep sequencing studies have revealed thousands of <span class="hlt">circular</span> noncoding RNAs generated from protein-coding genes. These RNAs are produced when the precursor messenger RNA (pre-mRNA) splicing machinery "backsplices" and covalently joins, for example, the two ends of a single exon. However, the mechanism by which the spliceosome selects only certain exons to <span class="hlt">circularize</span> is <span class="hlt">largely</span> unknown. Using extensive mutagenesis of expression plasmids, we show that miniature introns containing the splice sites along with short (?30- to 40-nucleotide) inverted repeats, such as Alu elements, are sufficient to allow the intervening exons to <span class="hlt">circularize</span> in cells. The intronic repeats must base-pair to one another, thereby bringing the splice sites into close proximity to each other. More than simple thermodynamics is clearly at play, however, as not all repeats support <span class="hlt">circularization</span>, and increasing the stability of the hairpin between the repeats can sometimes inhibit <span class="hlt">circular</span> RNA biogenesis. The intronic repeats and exonic sequences must collaborate with one another, and a functional 3' end processing signal is required, suggesting that <span class="hlt">circularization</span> may occur post-transcriptionally. These results suggest detailed and generalizable models that explain how the splicing machinery determines whether to produce a <span class="hlt">circular</span> noncoding RNA or a linear mRNA. PMID:25281217</p> <div class="credits"> <p class="dwt_author">Liang, Dongming; Wilusz, Jeremy E</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19800024703&hterms=scan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dz%2Bscan"> <span id="translatedtitle"><span class="hlt">Circular</span> Scan Streak Tube Development</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A streak tube having <span class="hlt">circular</span> scan was designed, built and tested. Continuous <span class="hlt">circular</span> scan, easily derived from out of phase sine waves applied to the conventional deflection plates, permits the timing of pulses traveling long baselines. At the tube's output a <span class="hlt">circular</span> array of 720 elements is scanned to provide 30 to 40 picosecond resolution. Initial difficulties with electron bombarded silicon arrays were circumvented by using microchannel plates within the streak tube to provide the needed electronic amplification and digital sensitivity and coupling the 720 element arrays to the electron beam by means of a phosphor on a fiber optics. Two ceramic body tubes with S-20 photocathodes were tested and delivered.</p> <div class="credits"> <p class="dwt_author">Nevin, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1980-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870052872&hterms=wenzel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dwenzel"> <span id="translatedtitle"><span class="hlt">Observations</span> of a <span class="hlt">large</span>-scale vortex-like structure in the deep-tail plasma sheet boundary layer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">ISEE-3 <span class="hlt">observations</span> of a <span class="hlt">large</span>-scale vortexlike structure in the deep tail of the magnetosphere at X(GSM) = -217 earth radii are reported. The structure is characterized by two clockwise rotations of the energetic-ion anisotropy vector. Variations in the magnetic-field vector approximately 180 deg out of phase with the ion variations are <span class="hlt">observed</span>. This structure is most likely the signature within the magnetosphere of a surface wave at the magnetopause driven by a Kelvin-Helmholtz instability. Conditions inside and outside of the magnetosphere, as <span class="hlt">observed</span> by ISEE-3 and ISEE-2, respectively, are examined; these conditions suggest that the surface wave is most likely propagating in the slow mode.</p> <div class="credits"> <p class="dwt_author">Sanderson, T. R.; Daly, P.; Wenzel, K.-P.; Hones, E. W., Jr.; Smith, E. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JASTP.121..110R"> <span id="translatedtitle">Fluctuations in the ionosphere related to Honshu Twin <span class="hlt">Large</span> Earthquakes of September 2004 <span class="hlt">observed</span> by the DEMETER and CHAMP satellites</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">While investigating possible precursory signatures of <span class="hlt">large</span> earthquakes in the ionospheric data measured by the DEMETER and CHAMP satellites, we found ionospheric disturbances related to <span class="hlt">large</span> earthquakes (M=7.2 and 7.4) that occurred on September 2004 near the south coast of Honshu, Japan. The satellite data were statistically compared with an empirical model and local averages of the <span class="hlt">large</span> set of data in the study period. A fluctuation in the electron density above the epicenter was <span class="hlt">observed</span> roughly 2 weeks before the main earthquakes. Surveys of the space weather and geomagnetic activities suggest that these fluctuations were not caused by changes in space conditions or by a geomagnetic storm. The features were also distinct from well-known natural ionospheric anomalies. In addition, a peak-like profile in the ion temperature and lowered O+ density around the region of the epicenter was <span class="hlt">observed</span> a week before the main earthquakes along the satellite passes whose longitudes are close to the epicenter. The features are more apparent when they are compared with the data more distant from the epicenter, suggesting that the disturbances occur along the geomagnetic field lines. The concurrent measurements of the ion drift velocity suggest the fluctuations were triggered by the vertical plasma drift. The <span class="hlt">observed</span> anomalies disappeared ? 2 weeks after the quakes. According to the current theories on the seismo-ionospheric coupling, the horizontal electric field at the lower boundary of the ionosphere should have been strengthened by the seismic activity in order for the ionospheric plasma movements above the epicenter and its geomagnetic conjugate regions to trigger the <span class="hlt">observed</span> ionospheric anomalies.</p> <div class="credits"> <p class="dwt_author">Ryu, Kwangsun; Chae, Jang-Soo; Lee, Ensang; Parrot, Michel</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ApJ...777...72S"> <span id="translatedtitle">SWAP <span class="hlt">Observations</span> of the Long-term, <span class="hlt">Large</span>-scale Evolution of the Extreme-ultraviolet Solar Corona</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Sun Watcher with Active Pixels and Image Processing (SWAP) EUV solar telescope on board the Project for On-Board Autonomy 2 spacecraft has been regularly <span class="hlt">observing</span> the solar corona in a bandpass near 17.4 nm since 2010 February. With a field of view of 54 × 54 arcmin, SWAP provides the widest-field images of the EUV corona available from the perspective of the Earth. By carefully processing and combining multiple SWAP images, it is possible to produce low-noise composites that reveal the structure of the EUV corona to relatively <span class="hlt">large</span> heights. A particularly important step in this processing was to remove instrumental stray light from the images by determining and deconvolving SWAP's point-spread function from the <span class="hlt">observations</span>. In this paper, we use the resulting images to conduct the first-ever study of the evolution of the <span class="hlt">large</span>-scale structure of the corona <span class="hlt">observed</span> in the EUV over a three year period that includes the complete rise phase of solar cycle 24. Of particular note is the persistence over many solar rotations of bright, diffuse features composed of open magnetic fields that overlie polar crown filaments and extend to <span class="hlt">large</span> heights above the solar surface. These features appear to be related to coronal fans, which have previously been <span class="hlt">observed</span> in white-light coronagraph images and, at low heights, in the EUV. We also discuss the evolution of the corona at different heights above the solar surface and the evolution of the corona over the course of the solar cycle by hemisphere.</p> <div class="credits"> <p class="dwt_author">Seaton, Daniel B.; De Groof, Anik; Shearer, Paul; Berghmans, David; Nicula, Bogdan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22270641"> <span id="translatedtitle">SWAP <span class="hlt">OBSERVATIONS</span> OF THE LONG-TERM, <span class="hlt">LARGE</span>-SCALE EVOLUTION OF THE EXTREME-ULTRAVIOLET SOLAR CORONA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The Sun Watcher with Active Pixels and Image Processing (SWAP) EUV solar telescope on board the Project for On-Board Autonomy 2 spacecraft has been regularly <span class="hlt">observing</span> the solar corona in a bandpass near 17.4 nm since 2010 February. With a field of view of 54 × 54 arcmin, SWAP provides the widest-field images of the EUV corona available from the perspective of the Earth. By carefully processing and combining multiple SWAP images, it is possible to produce low-noise composites that reveal the structure of the EUV corona to relatively <span class="hlt">large</span> heights. A particularly important step in this processing was to remove instrumental stray light from the images by determining and deconvolving SWAP's point-spread function from the <span class="hlt">observations</span>. In this paper, we use the resulting images to conduct the first-ever study of the evolution of the <span class="hlt">large</span>-scale structure of the corona <span class="hlt">observed</span> in the EUV over a three year period that includes the complete rise phase of solar cycle 24. Of particular note is the persistence over many solar rotations of bright, diffuse features composed of open magnetic fields that overlie polar crown filaments and extend to <span class="hlt">large</span> heights above the solar surface. These features appear to be related to coronal fans, which have previously been <span class="hlt">observed</span> in white-light coronagraph images and, at low heights, in the EUV. We also discuss the evolution of the corona at different heights above the solar surface and the evolution of the corona over the course of the solar cycle by hemisphere.</p> <div class="credits"> <p class="dwt_author">Seaton, Daniel B.; De Groof, Anik; Berghmans, David; Nicula, Bogdan [Royal Observatory of Belgium-SIDC, Avenue Circulaire 3, B-1180 Brussels (Belgium); Shearer, Paul [Department of Mathematics, 2074 East Hall, University of Michigan, 530 Church Street, Ann Arbor, MI 48109-1043 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19960021326&hterms=voyager&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dvoyager"> <span id="translatedtitle">Merged interaction regions and <span class="hlt">large</span>-scale fluctuations <span class="hlt">observed</span> by the Voyager 2 in the distant heliosphere</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The merged interaction regions (MIRs) and <span class="hlt">large</span>-scale fluctuations of the heliospheric magnetic field play a major role in the dynamics of the solar wind, the position and motion of the termination shock and heliopause, the triggering of radio emissions, and the modulation of cosmic rays. The structure of MIRs and <span class="hlt">large</span>-scale fluctuations varies with distance from the sun and with solar activity. Here we compare Voyager 2 <span class="hlt">observations</span> near the maximum of solar activity (1989 through 1991) with those during the declining phase of solar activity (1992 thorough 1994). Global MIRs with strong magnetic fields, preceded by a strong shock, were <span class="hlt">observed</span> near solar maximum. During the declining phase of the solar cycle, the MIRs had significantly weaker magnetic fields. In both cases the pickup protons, identified by an analysis of pressure balanced structures, play a major role in the dynamical evolution of the MIRs beyond 30 AU. The <span class="hlt">large</span>-scale magnetic field fluctuations have significantly greater amplitudes near solar maximum than during the declining phase of the solar cycle.</p> <div class="credits"> <p class="dwt_author">Burlaga, L. F.; Ness, N. F.</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25341745"> <span id="translatedtitle">Nuclear spin <span class="hlt">circular</span> dichroism in fullerenes: a computational study.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In the recently proposed phenomenon, nuclear spin-induced <span class="hlt">circular</span> dichroism (NSCD), collective magnetisation of nuclei induces <span class="hlt">circular</span> dichroism in a light beam passing through a molecular sample. Here we present the first computational predictions of NSCD for fullerenes C60 and C70. We show that the NSCD signal is nucleus-specific, like in NMR spectroscopy. Thus, NSCD may provide a new and promising, high-resolution <span class="hlt">observable</span> for experimental identification of chemical compounds. PMID:25341745</p> <div class="credits"> <p class="dwt_author">Straka, Michal; St?pánek, Petr; Coriani, Sonia; Vaara, Juha</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22707722"> <span id="translatedtitle">Biological synthesis of <span class="hlt">circular</span> polypeptides.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Here, we review the use of different biochemical approaches for biological synthesis of <span class="hlt">circular</span> or backbone-cyclized proteins and peptides. These methods allow the production of <span class="hlt">circular</span> polypeptides either in vitro or in vivo using standard recombinant DNA expression techniques. Protein <span class="hlt">circularization</span> can significantly impact protein engineering and research in protein folding. Basic polymer theory predicts that <span class="hlt">circularization</span> should lead to a net thermodynamic stabilization of a folded protein by reducing the entropy associated with the unfolded state. Protein cyclization also provides a valuable tool for exploring the effects of topology on protein folding kinetics. Furthermore, the biological production of cyclic polypeptides makes possible the production of cyclic polypeptide libraries. The generation of such libraries, which was previously restricted to the domain of synthetic chemists, now offers biologists access to highly diverse and stable molecular libraries for probing protein structure and function. PMID:22707722</p> <div class="credits"> <p class="dwt_author">Aboye, Teshome L; Camarero, Julio A</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22034336"> <span id="translatedtitle">325 MHz VERY <span class="hlt">LARGE</span> ARRAY <span class="hlt">OBSERVATIONS</span> OF ULTRACOOL DWARFS TVLM 513-46546 AND 2MASS J0036+1821104</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present 325 MHz (90 cm wavelength) radio <span class="hlt">observations</span> of ultracool dwarfs TVLM 513-46546 and 2MASS J0036+1821104 using the Very <span class="hlt">Large</span> Array (VLA) in 2007 June. Ultracool dwarfs are expected to be undetectable at radio frequencies, yet <span class="hlt">observations</span> at 8.5 GHz (3.5 cm) and 4.9 GHz (6 cm) have revealed sources with >100 {mu}Jy quiescent radio flux and >1 mJy pulses coincident with stellar rotation. The anomalous emission is likely a combination of gyrosynchrotron and cyclotron maser processes in a long-duration, <span class="hlt">large</span>-scale magnetic field. Since the characteristic frequency for each process scales directly with the magnetic field magnitude, emission at lower frequencies may be detectable from regions with weaker field strength. We detect no significant radio emission at 325 MHz from TVLM 513-46546 or 2MASS J0036+1821104 over multiple stellar rotations, establishing 2.5{sigma} total flux limits of 795 {mu}Jy and 942 {mu}Jy, respectively. Analysis of an archival VLA 1.4 GHz <span class="hlt">observation</span> of 2MASS J0036+1821104 from 2005 January also yields a non-detection at the level of <130 {mu}Jy. The combined radio <span class="hlt">observation</span> history (0.3 GHz to 8.5 GHz) for these sources suggests a continuum emission spectrum for ultracool dwarfs that is either flat or inverted below 2-3 GHz. Further, if the cyclotron maser instability is responsible for the pulsed radio emission <span class="hlt">observed</span> on some ultracool dwarfs, our low-frequency non-detections suggest that the active region responsible for the high-frequency bursts is confined within two stellar radii and driven by electron beams with energies less than 5 keV.</p> <div class="credits"> <p class="dwt_author">Jaeger, T. R.; Kassim, N. [US Naval Research Laboratory, Washington, DC 20375 (United States); Osten, R. A. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Lazio, T. J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Mutel, R. L., E-mail: ted.jaeger.ctr@nrl.navy.mil [Department of Astronomy, University of Iowa, Iowa City, IA 52242 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFM.A53D..02B"> <span id="translatedtitle"><span class="hlt">Large</span>-Scale Air Mass Characteristics <span class="hlt">Observed</span> Over North America and the Western Atlantic Ocean During INTEX-A/ICARTT</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Large</span>-scale measurements of ozone (O3) and aerosol distributions were made from the NASA DC-8 aircraft during the INTEX-A/ICARTT field experiment conducted from July 1-August 14, 2004. Remote measurements were made with an airborne lidar to provide O3 and multiple-wavelength aerosol backscatter profiles from near the surface to above the tropopause along the flight track. Aerosol depolarization measurements were also made for the detection of nonspherical aerosols, such as mineral dust and aerosols in fire plumes. In situ measurements of O3, aerosols, and a wide range of trace gases were made onboard the DC-8 and correlated with the remote lidar measurements. Meteorological analyses of potential vorticity distributions along the flight track were used to indicate the fraction of <span class="hlt">observed</span> O3 that could be attributed to stratosphere-troposphere exchange. Five-day backward trajectories were also used to indicate the possible origin of <span class="hlt">observed</span> air masses. Frequent mixtures of stratospheric air mixed with polluted tropospheric air masses were <span class="hlt">observed</span> in the middle and upper troposphere. Exhanced O3 concentrations and aerosol loading in the lower troposphere were found to be associated with U.S. pollution and advection of those air masses over the Atlantic Ocean. Long-range transport of fire plumes from Alaska were frequently <span class="hlt">observed</span> with depolarizing aerosols over eastern North America. Average latitudinal O3 and aerosol distributions were determined and related to <span class="hlt">large</span>-scale atmospheric processes. This paper discusses the types and characteristics of air masses that were encountered during this field experiment, including their frequency and location (latitude and altitude) of <span class="hlt">observations</span>, and relates them to different processes responsible for determining their characteristics.</p> <div class="credits"> <p class="dwt_author">Browell, E. V.; Fenn, M. A.; Hair, J. W.; Butler, C. F.; Notari, A.; Kooi, S. A.; Ismail, S.; Avery, M. A.; Pierce, R. B.; Fuelberg, H. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014DPS....4620006H"> <span id="translatedtitle"><span class="hlt">Observations</span> of Comet P/2003 T12 = 2012 A3 (SOHO) at <span class="hlt">large</span> phase angle in STEREO-B</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Comet P/2003 T12 = 2012 A3 (SOHO) was <span class="hlt">observed</span> by the satellite STEREO-B during the period 2012 January 13-27. During its apparition, it ventured into the highest phase angle ever <span class="hlt">observed</span> for a comet, and the forward-scattering enhancement in brightness was marked, as <span class="hlt">large</span> as ?8.5 mag. Therefore, it provided a precious opportunity to examine the compound Henyey-Greenstein (HG) comet-dust light-scattering model and it also offered valuable polarization data under an unprecedented <span class="hlt">observing</span> geometry. Our analysis reveals that the compound HG model fits the <span class="hlt">observations</span> very well until the phase angle exceeds ?173°, where the brightness surge of the comet was obviously steeper than the prediction by the model. We have found that the reason for the greater steepness cannot be explained by contaminations from the proximal tail. Instead, the model of Mie spheres with radii greater than 1 ?m, having a power-law distribution of power index ?3, matches the <span class="hlt">observation</span> very well, providing a best-fitting complex refractive index ? = 1.38 + i 0.006. The dust size was found to be consistent with the analysis of the comet's syndyne lines. The debiased polarization of the coma was ?0 per cent in the phase angle range from 172.9° to 177.6°. No convincing evidence of temporal variation of the polarization was detected.</p> <div class="credits"> <p class="dwt_author">Hui, Man-To</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MNRAS.436.1564H"> <span id="translatedtitle"><span class="hlt">Observations</span> of Comet P/2003 T12 = 2012 A3 (SOHO) at <span class="hlt">large</span> phase angle in STEREO-B</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Comet P/2003 T12 = 2012 A3 (SOHO) was <span class="hlt">observed</span> by the satellite STEREO-B during the period 2012 January 13-27. During its apparition, it ventured into the highest phase angle ever <span class="hlt">observed</span> for a comet, and the forward-scattering enhancement in brightness was marked, as <span class="hlt">large</span> as ˜8.5 mag. Therefore, it provided a precious opportunity to examine the compound Henyey-Greenstein (HG) comet-dust light-scattering model and it also offered valuable polarization data under an unprecedented <span class="hlt">observing</span> geometry. Our analysis reveals that the compound HG model fits the <span class="hlt">observations</span> very well until the phase angle exceeds ˜173°, where the brightness surge of the comet was obviously steeper than the prediction by the model. We have found that the reason for the greater steepness cannot be explained by contaminations from the proximal tail. Instead, the model of Mie spheres with radii greater than 1 ?m, having a power-law distribution of power index ˜3, matches the <span class="hlt">observation</span> very well, providing a best-fitting complex refractive index ? = 1.38 + i 0.006. The dust size was found to be consistent with the analysis of the comet's syndyne lines. The debiased polarization of the coma was ˜0 per cent in the phase angle range from 172.9° to 177.6°. . No convincing evidence of temporal variation of the polarization was detected.</p> <div class="credits"> <p class="dwt_author">Hui, M.-T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22047754"> <span id="translatedtitle">SIMULTANEOUS <span class="hlt">OBSERVATIONS</span> OF A <span class="hlt">LARGE</span>-SCALE WAVE EVENT IN THE SOLAR ATMOSPHERE: FROM PHOTOSPHERE TO CORONA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">For the first time, we report a <span class="hlt">large</span>-scale wave that was <span class="hlt">observed</span> simultaneously in the photosphere, chromosphere, transition region, and low corona layers of the solar atmosphere. Using the high temporal and high spatial resolution <span class="hlt">observations</span> taken by the Solar Magnetic Activity Research Telescope at Hida Observatory and the Atmospheric Imaging Assembly (AIA) on board Solar Dynamic Observatory, we find that the wave evolved synchronously at different heights of the solar atmosphere, and it propagated at a speed of 605 km s{sup -1} and showed a significant deceleration (-424 m s{sup -2}) in the extreme-ultraviolet (EUV) <span class="hlt">observations</span>. During the initial stage, the wave speed in the EUV <span class="hlt">observations</span> was 1000 km s{sup -1}, similar to those measured from the AIA 1700 A (967 km s{sup -1}) and 1600 A (893 km s{sup -1}) <span class="hlt">observations</span>. The wave was reflected by a remote region with open fields, and a slower wave-like feature at a speed of 220 km s{sup -1} was also identified following the primary fast wave. In addition, a type-II radio burst was <span class="hlt">observed</span> to be associated with the wave. We conclude that this wave should be a fast magnetosonic shock wave, which was first driven by the associated coronal mass ejection and then propagated freely in the corona. As the shock wave propagated, its legs swept the solar surface and thereby resulted in the wave signatures <span class="hlt">observed</span> in the lower layers of the solar atmosphere. The slower wave-like structure following the primary wave was probably caused by the reconfiguration of the low coronal magnetic fields, as predicted in the field-line stretching model.</p> <div class="credits"> <p class="dwt_author">Shen, Yuandeng; Liu, Yu, E-mail: ydshen@ynao.ac.cn [Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming 650011 (China)</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-06-20</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/1034449"> <span id="translatedtitle"><span class="hlt">Observations</span> of <span class="hlt">Large</span> Scale Sidereal Anisotropy in 1 and 11 TeV cosmic rays from the MINOS experiment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The MINOS Near and Far Detectors are two <span class="hlt">large</span>, functionally-identical, steel-scintillating sampling calorimeters located at depths of 220 mwe and 2100 mwe respectively. The detectors <span class="hlt">observe</span> the muon component of hadronic showers produced from cosmic ray interactions with nuclei in the earth's atmosphere. From the arrival direction of these muons, the anisotropy in arrival direction of the cosmic ray primaries can be determined. The MINOS Near and Far Detector have <span class="hlt">observed</span> anisotropy on the order of 0.1% at 1 and 11 TeV respectively. The amplitude and phase of the first harmonic at 1 TeV are 8.2 {+-} 1.7(stat.) x 10{sup -4} and (8.9 {+-} 12.1(stat.)){sup o}, and at 11 TeV are 3.8 {+-} 0.5(stat.) x 10{sup -4} and (27.2 {+-} 7.2(stat.)){sup o}.</p> <div class="credits"> <p class="dwt_author">de Jong, J.K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011ICRC....4...46D"> <span id="translatedtitle"><span class="hlt">Observations</span> of <span class="hlt">Large</span> Scale Sidereal Anisotropy in 1 and 11 TeV cosmic rays from the MINOS experiment.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The MINOS Near and Far Detectors are two <span class="hlt">large</span>, functionally-identical, steel-scintillating sampling calorimeters located at depths of 220 mwe and 2100 mwe respectively. The detectors <span class="hlt">observe</span> the muon component of hadronic showers produced from cosmic ray interactions with nuclei in the earth's atmosphere. From the arrival direction of these muons, the anisotropy in arrival direction of the cosmic ray primaries can be determined. The MINOS Near and Far Detector have <span class="hlt">observed</span> anisotropy on the order of 0.1% at 1 and 11 TeV respectively. The amplitude and phase of the first harmonic at 1 TeV are 8.2$\\pm$1.7(stat.)$\\times 10^{-4}$ and (8.9$\\pm$12.1(stat.))$^{\\circ}$, and at 11 TeV are 3.8$\\pm$0.5(stat.)$\\times 10^{-4}$ and (27.2$\\pm$7.2(stat.))$^{\\circ}$.</p> <div class="credits"> <p class="dwt_author">DE JONG, Jeffrey</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/0711.3952v1"> <span id="translatedtitle"><span class="hlt">Large</span>-Amplitude Oscillation of an Erupting Filament as Seen in EUV, H-alpha and Microwave <span class="hlt">Observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We present multiwavelength <span class="hlt">observations</span> of a <span class="hlt">large</span>-amplitude oscillation of a polar crown filament on 15 October 2002. The oscillation occurred during the slow rise (about 1 km/s) of the filament. It completed three cycles before sudden acceleration and eruption. The oscillation and following eruption were clearly seen in <span class="hlt">observations</span> recorded by the Extreme-Ultraviolet Imaging Telescope onboard SOHO. The oscillation was seen only in a part of the filament, and it appears to be a standing oscillation rather than a propagating wave. The period of oscillation was about two hours and did not change significantly during the oscillation. We also identified the oscillation as a "winking filament" in the H-alpha images taken by the Flare Monitoring Telescope, and as a spatial displacement in 17 GHz microwave images from Nobeyama Radio Heliograph (NoRH). The filament oscillation seems to be triggered by magnetic reconnection between a filament barb and nearby emerging magnetic flux as was evident from the MDI magnetogram <span class="hlt">observations</span>. No flare was <span class="hlt">observed</span> to be associated with the onset of the oscillation. We also discuss possible implications of the oscillation as a diagnostic tool for the eruption mechanisms. We suggest that in the early phase of eruption a part of the filament lost its equilibrium first, while the remaining part was still in an equilibrium and oscillated.</p> <div class="credits"> <p class="dwt_author">H. Isobe; D. Tripathi; A. Asai; R. Jain</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-11-26</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFMSM41C1199B"> <span id="translatedtitle">Acceleration and Precipitation of Energetic Ionospheric Ion Beams in the Auroral Region: Cluster <span class="hlt">Observations</span> and <span class="hlt">Large</span> Scale Modeling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Cluster spacecraft offer a unique opportunity to investigate the origin of dispersed ion beams <span class="hlt">observed</span> at mid-latitudes (4-5 RE) in the nightside auroral region. In this paper we present a detailed study of one event <span class="hlt">observed</span> during the recovery phase of a magnetospheric substorm. In contrast to the suggestion that energetic ions sporadically originate in the distant PSBL, we argue that energetic (5-15 keV), field-aligned H+ ions <span class="hlt">observed</span> by Cluster are ejected at the top of a steady and localized auroral acceleration region. These ions bounce on closed field-lines and are dispersed in latitude by the E x B magnetospheric filter. Echoes of energetic ionospheric H+ ions are <span class="hlt">observed</span> by each of the Cluster spacecraft as they pass through the high latitude poleward edge of the plasmasheet. Such multiple-spacecraft measurements are well-suited to test our ability to model very complex magnetospheric situations. Detailed time-dependent modeling of this event will be presented. In order to correctly interpret the <span class="hlt">observed</span> spatial dispersion, global MHD simulations demonstrate that vortices or channels of tailward convection are locally generated in the neutral sheet at 14-18 RE distance in the post-midnight sector, i.e., on field lines connected with the mid-altitude region crossed by Cluster. By using the <span class="hlt">Large</span> Scale Kinetic (LSK) approach, millions of ion trajectories are followed in the time-dependent MHD fields, starting from an ionospheric source. These particles undergo very complex orbits, some of them are on adiabatic bouncing orbits but a non-negligible fraction are non-adiabatically accelerated during neutral sheet crossings and supply part of the <span class="hlt">observed</span> echoes.</p> <div class="credits"> <p class="dwt_author">Bosqued, J. M.; Ashour-Abdalla, M.; Umeda, T.; El Alaoui, M.; Peroomian, V.; Marchaudon, A.; Dunlop, M. W.; Paschmann, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008P%26SS...56..398D"> <span id="translatedtitle"><span class="hlt">Large</span>-scale solar wind density enhancement and its boundaries: Helios 1, 2 and IMP 8 <span class="hlt">observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the present paper, we investigate a <span class="hlt">large</span> pulse in the solar wind density <span class="hlt">observed</span> on April 1-2, 1977 by the Helios 1, 2 probes and 2 days later by the IMP 8 spacecraft in the "line-up" condition (all three spacecraft had the positions along the Sun-Earth line). In this pulse the strong enhancement in density (˜50% relative to the undisturbed level) was not accompanied by significant changes in other main solar wind parameters. The outcomes of detailed analysis of physical properties as well as of geometrical features of the <span class="hlt">observed</span> plasma pulse structure are discussed. One of the characteristic peculiarities of this pulse was its sharp boundaries (with durations of several minutes only). The main scientific result of our study is that the trailing edge of the pulse was found to be very stable (conserved its shape and duration) propagating over as <span class="hlt">large</span> distance as 0.6 AU (90×10 6 km) or during 2.3 days of the solar wind motion.</p> <div class="credits"> <p class="dwt_author">Dalin, P. A.; Yermolaev, Yu. I.; Zastenker, G. N.; Riazantseva, M. O.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820005721&hterms=land+snail+magnetic+field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dland%2Bsnail%2Bmagnetic%2Bfield"> <span id="translatedtitle"><span class="hlt">Large</span>-scale variations of the interplanetary magnetic field: Voyager 1 and 2 <span class="hlt">observations</span> between 1-5 AU</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><span class="hlt">Observations</span> by the Voyager 1 and 2 spacecraft of the interplanetary magnetic field between 1 and 5 AU were used to investigate the <span class="hlt">large</span> scale structure of the IMF in a period of increasing solar activity. The Voyager spacecraft found notable deviations from the Parker axial model. These deviations are attributed both to temporal variations associated with increasing solar activity, and to the effects of fluctuations of the field in the radial direction. The amplitude of the latter fluctuations were found to be <span class="hlt">large</span> relative to the magnitude of the radial field component itself beyond approximately 3 AU. Both Voyager 1 and Voyager 2 <span class="hlt">observed</span> decreases with increasing heliocentric distance in the amplitude of transverse fluctuations in the averaged field strength (B) which are consistent with the presence of predominantly undamped Alfven waves in the solar wind, although and necessarily implying the presence of them. Fluctuations in the strength of B (relative to mean field strength) were found to be small in amplitude, with a RMS which is approximately one third of that for the transverse fluctuations and they are essentially independent of distance from the Sun.</p> <div class="credits"> <p class="dwt_author">Burlaga, L. F.; Lepping, R. P.; Behannon, K. W.; Klein, L. W.; Neubauer, F. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006cosp...36.1858B"> <span id="translatedtitle">Using multi-spacecraft <span class="hlt">observations</span> and simulations to determine the <span class="hlt">large</span>-scale topology of the dayside magnetospheric boundary</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Multi-spacecraft <span class="hlt">observations</span> offer a unique opportunity to evaluate global models in simulating the complex topology and dynamics of the dayside magnetosphere The principle of these studies consists of using interplanetary magnetic field IMF and plasma parameters measured by solar wind monitors upstream of the bow shock as input to the simulations The validity of the <span class="hlt">large</span>-scale topological features deduced from the simulations is then tested by comparing local data streams from the simulations with spacecraft time series In this paper we review recent progress in using three-dimensional global magnetohydrodynamic MHD simulations to model the <span class="hlt">large</span>-scale topology and dynamics of magnetic reconnection at the dayside magnetosphere by comparing their predictions with <span class="hlt">observations</span> from the DOUBLE STAR TC1 and CLUSTER spacecraft Results of these studies emphasize the importance of the locations where discontinuities embedded in the solar wind impact the magnetosphere as well as the effects of the time evolution of the draping of the magnetosheath field in the global merging process and hence the invaluable insight provided by global simulations</p> <div class="credits"> <p class="dwt_author">Berchem, J.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013ARep...57..485S"> <span id="translatedtitle">Statistical analysis of the <span class="hlt">large</span>-scale structure of the Universe using <span class="hlt">observational</span> data and numerical modeling</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The statistical properties of elements of the <span class="hlt">large</span>-scale structure of the Universe are studied using the SDSS DR7 galaxy catalog and a dark-matter halo catalog obtained via numerical modeling using MultiDark Run1. The minimum spanning tree technique is used to distinguish the <span class="hlt">large</span>-scale structure, and the Core Sampling method is used to analyze its properties. As a result, the SDSS DR7 and MultiDark Run1 catalogs are divided into subcatalogs of two-dimensonal walls and one-dimensional filaments. Some statistical properties of these subcatalogs are compared with theoretical predictions. The mean separation between the walls is measured using both the <span class="hlt">observations</span> and numerical modeling results (50-60 Mpc/ h) and the distribution of the wall surface density is derived. The fraction of the SDSS DR7 galaxy clusters thought to have been distorted by the <span class="hlt">observational</span> effect called "fingers of God" is estimated. Dense clusters for which this effect is most appreciable constitute ˜15% of the analyzed clusters. The influence of these clusters on the final result is eliminated by fitting the orientation of test cylinders in the Core Sampling method.</p> <div class="credits"> <p class="dwt_author">Semenov, V. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFMSH53A1261H"> <span id="translatedtitle"><span class="hlt">Observations</span> of <span class="hlt">Large</span> Amplitude Electrostatic Waves Associated with Magnetic Ramp Substructure at Earth's Bow Shock by Polar</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present Polar-EFI <span class="hlt">observations</span> of electrostatic (ES) waves at high frequency (100 Hz < f < 4000 Hz) at Earth's bow shock under extreme solar wind conditions. Polar-EFI provides the first 3-axis measurements of electric fields across the shock layer, allowing for a better evaluation of the electric field properties than previous missions. The ES waveforms are of <span class="hlt">large</span> amplitude (as <span class="hlt">large</span> as 20-100 mV/m), and have both parallel and perpendicular components. Although we have <span class="hlt">observed</span> solitary waves, the most prevalent structures in the magnetic ramp are <span class="hlt">large</span> amplitude ES wave packets usually lasting from 10-30 cycles. These structures have wavelengths of a few hundred meters (e.g., ~ 10 Debeye Lengths) and are convecting by the spacecraft at speeds from 50 km/s to > 800 km/s. In the events presented, the ES wave power is generally well correlated with maxima in the magnetic ramp substructure, suggesting that these local maxima are important sites for the generation of these waves. These waveforms are not consistent with the classical ion acoustic wave description, since they occur under conditions where T_e~ T_i at local magnetic field maxima as opposed to the gradient and they propagate at oblique angles to the magnetic field. The fact that these waves are collocated with magnetic maxima is suggestive that the free-energy source of these waves may be from phase-space holes in the electron distribution, as a result of the acceleration of the low energy part of electron phase space by the shock DC electric field.</p> <div class="credits"> <p class="dwt_author">Hull, A. J.; Larson, D.; Mozer, F.; Wilber, M.; Bale, S.; Scudder, J.; Russell, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014NatCo...5E4922Z"> <span id="translatedtitle">Angular momentum-induced <span class="hlt">circular</span> dichroism in non-chiral nanostructures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Circular</span> dichroism, that is, the differential absorption of a system to left and right <span class="hlt">circularly</span> polarized light, is one of the only techniques capable of providing morphological information of certain samples. In biology, for instance, <span class="hlt">circular</span> dichroism spectroscopy is widely used to study the structure of proteins. More recently, it has also been used to characterize metamaterials and plasmonic structures. Typically, <span class="hlt">circular</span> dichorism can only be <span class="hlt">observed</span> in chiral objects. Here we present experimental results showing that a non-chiral sample such as a subwavelength <span class="hlt">circular</span> nanoaperture can produce giant <span class="hlt">circular</span> dichroism when a vortex beam is used to excite it. These measurements can be understood by studying the symmetries of the sample and the total angular momentum that vortex beams carry. Our results show that <span class="hlt">circular</span> dichroism can provide a wealth of information about the sample when combined with the control of the total angular momentum of the input field.</p> <div class="credits"> <p class="dwt_author">Zambrana-Puyalto, Xavier; Vidal, Xavier; Molina-Terriza, Gabriel</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25215603"> <span id="translatedtitle">Angular momentum-induced <span class="hlt">circular</span> dichroism in non-chiral nanostructures.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Circular</span> dichroism, that is, the differential absorption of a system to left and right <span class="hlt">circularly</span> polarized light, is one of the only techniques capable of providing morphological information of certain samples. In biology, for instance, <span class="hlt">circular</span> dichroism spectroscopy is widely used to study the structure of proteins. More recently, it has also been used to characterize metamaterials and plasmonic structures. Typically, <span class="hlt">circular</span> dichorism can only be <span class="hlt">observed</span> in chiral objects. Here we present experimental results showing that a non-chiral sample such as a subwavelength <span class="hlt">circular</span> nanoaperture can produce giant <span class="hlt">circular</span> dichroism when a vortex beam is used to excite it. These measurements can be understood by studying the symmetries of the sample and the total angular momentum that vortex beams carry. Our results show that <span class="hlt">circular</span> dichroism can provide a wealth of information about the sample when combined with the control of the total angular momentum of the input field. PMID:25215603</p> <div class="credits"> <p class="dwt_author">Zambrana-Puyalto, Xavier; Vidal, Xavier; Molina-Terriza, Gabriel</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014MNRAS.444.3308P"> <span id="translatedtitle">Positions of equilibrium points for dust particles in the <span class="hlt">circular</span> restricted three-body problem with radiation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">For a body with negligible mass moving in the gravitational field of a star with one planet in a <span class="hlt">circular</span> orbit (the <span class="hlt">circular</span> restricted three-body problem), five equilibrium points exist and are known as the Lagrangian points. The positions of the Lagrangian points are not valid for dust particles because in the derivation of the Lagrangian points it is assumed that no other forces besides the gravitation act on the body with negligible mass. Here, we determined positions of the equilibrium points for the dust particles in the <span class="hlt">circular</span> restricted three-body problem with radiation. The equilibrium points are located on curves connecting the Lagrangian points in the <span class="hlt">circular</span> restricted three-body problem. The equilibrium points for Jupiter are distributed in <span class="hlt">large</span> interval of heliocentric distances due to its <span class="hlt">large</span> mass. The equilibrium points for the Earth explain a cloud of dust particles trailing the Earth <span class="hlt">observed</span> with the Spitzer Space Telescope. The dust particles moving in the equilibrium points are distributed in interplanetary space according to their properties.</p> <div class="credits"> <p class="dwt_author">Pástor, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/astro-ph/0603176v1"> <span id="translatedtitle">Radio <span class="hlt">Observations</span> of a <span class="hlt">Large</span> Sample of Late-M, L, and T Dwarfs: The Distribution of Magentic Field Strengths</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We present radio <span class="hlt">observations</span> of a comprehensive sample of 90 dwarf stars and brown dwarfs ranging from spectral type M5 to T8. We detect three radio active sources in addition to the six objects previously detected in quiescence and outburst, leading to an overall detection rate of about 10% for objects later than M7. From the properties of the radio emission we infer magnetic field strengths of ~100 G in quiescence and nearly 1 kG during flares, while the majority of the non-detected objects have B-12, (ii) increased radio activity with later spectral type, in contrast to H-alpha and X-ray <span class="hlt">observations</span>, and (iii) an overall drop in the fraction of active sources from about 30% for M dwarfs to about 5% for L dwarfs, fully consistent with H-alpha and X-ray <span class="hlt">observations</span>. Taken together, these trends suggest that some late-M and L dwarfs are capable of generating 0.1-1 kG magnetic fields, but the overall drop in the fraction of such objects is likely accompanied by a change in the structure of the chromospheres and coronae, possibly due to the increasingly neutral atmospheres and/or a transition to a turbulent dynamo. A more extended radio survey currently holds the best promise for measuring the magnetic field properties of a <span class="hlt">large</span> number of dwarf stars. [abridged</p> <div class="credits"> <p class="dwt_author">Edo Berger</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-03-07</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvL.113o5501I"> <span id="translatedtitle">Direct <span class="hlt">Observation</span> of Dopant Atom Diffusion in a Bulk Semiconductor Crystal Enhanced by a <span class="hlt">Large</span> Size Mismatch</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Diffusion is one of the fundamental processes that govern the structure, processing, and properties of materials and it plays a crucial role in determining device lifetimes. However, direct <span class="hlt">observations</span> of diffusion processes have been elusive and limited only to the surfaces of materials. Here we use an aberration-corrected electron microscope to locally excite and directly image the diffusion of single Ce and Mn dopants inside bulk wurtzite-type AlN single crystals, identifying correlated vacancy-dopant and interstitial-dopant kick-out mechanisms. Using a 200 kV electron beam to supply energy, we <span class="hlt">observe</span> a higher frequency of dopant jumps for the larger and heavier Ce atoms than the smaller Mn atoms. These <span class="hlt">observations</span> confirm density-functional-theory-based predictions of a decrease in diffusion barrier for <span class="hlt">large</span> substitutional atoms. The results show that combining depth sensitive microscopy with theoretical calculations represents a new methodology to investigate diffusion mechanisms, not restricted to surface phenomena, but within bulk materials.</p> <div class="credits"> <p class="dwt_author">Ishikawa, Ryo; Mishra, Rohan; Lupini, Andrew R.; Findlay, Scott D.; Taniguchi, Takashi; Pantelides, Sokrates T.; Pennycook, Stephen J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..1412499V"> <span id="translatedtitle"><span class="hlt">Circular</span>-polarization ratios for aggregates of spherical particles</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A basic strategy for <span class="hlt">observing</span> a small solar-system object using radar is to measure the distribution of echo power in time delay and Doppler frequency for a <span class="hlt">circularly</span> polarized transmitted wave, in the same and opposite senses of <span class="hlt">circular</span> polarization. The measurement can be repeated for differing orientations and plane-of-sky directions of the object. The <span class="hlt">circular</span>-polarization ratio ? is the ratio of the echo power in the same <span class="hlt">circular</span>-polarization state (SC) to that in the opposite <span class="hlt">circular</span>-polarization state (OC). The ratio ? is often the most important physical <span class="hlt">observable</span> with the radar technique, as it provides the best indications for wavelength-scale complexity of the surface. At the typical transmitter frequencies of 2380 MHz or 8495 MHz, the wavelengths are 12.6 cm or 3.5 cm, respectively. We model electromagnetic scattering from closely-packed random aggregates of spheres imitating the structure of an asteroid's regolith. Both scattering and absorption of the electromagnetic wave are treated. The Multiple-Sphere T -Matrix Method computer software (MSTM; D. W. Mackowski and M. I. Mishchenko, JQSRT 112, 1282, 2011) is utilized to study how different parameters affect the <span class="hlt">circular</span>-polarization ratio, e.g., the size distribution and electric permittivities of the spherical particles forming the different aggregates. Our primary goal is to see if the computed <span class="hlt">circular</span>-polarization ratios can be linked to the <span class="hlt">observational</span> data of asteroids detected with radar. The results of the simulations show striking structure for the <span class="hlt">circular</span>-polarization ratio as a function of the size parameter and the electric permittivity of the medium. Also differences between aggregates of monodisperse and polydisperse spheres clearly exist: the aggregates consisting of polydisperse spherical particles, and hence, showing more complex structure and surface, result in <span class="hlt">circular</span>-polarization ratios higher than the aggregates of monodisperse spherical particles, probably due to the increased significance of multiple scattering. Most importantly, the simulations show how the variations of the different parameters affect the ratio, indicating reasons for the variations in the <span class="hlt">observed</span> data. We have simulated <span class="hlt">circular</span>-polarization ratios for aggregates of monodisperse particles, and are currently initiating simulations for aggregates of polydisperse spheres.</p> <div class="credits"> <p class="dwt_author">Virkki, A.; Muinonen, K.; Penttilä, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/12317499"> <span id="translatedtitle">[Family Planning <span class="hlt">Circular</span> of 1990].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In 1990, the government of Guangdong issued a Family Planning <span class="hlt">Circular</span> demanding that the people of Guangdong take immediate actions to push ahead with Guangdong's family planning (FP) work. The <span class="hlt">Circular</span> provides that, despite the fact that Guangdong has achieved gratifying results in its FP work this year, it has failed to fulfill its FP quotas and check excessive population growth for 4 successive years in the 7th 5-Year period. The <span class="hlt">Circular</span> also provides that, in view of this rigorous situation, the Government demands that people's governments at all levels in Guangdong immediately formulate specific plans aimed at fully implementing to the FP quotas and an FP-oriented responsibility system at all levels. All concerned departments and mass organizations in Guangdong are required actively to cooperate and coordinate with one another in carrying out FP work. PMID:12317499</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1990-05-10</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003ApJ...582.1073O"> <span id="translatedtitle">Chandra, Extreme Ultraviolet Explorer, and Very <span class="hlt">Large</span> Array <span class="hlt">Observations</span> of the Active Binary System ?2 Coronae Borealis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present the results of a coordinated <span class="hlt">observing</span> campaign on the short-period RS CVn binary ?2 Coronae Borealis (F6V+G0V Porb=1.14 days) with the Very <span class="hlt">Large</span> Array, the Extreme Ultraviolet Explorer, and the Chandra X-Ray Observatory High-Energy Transmission Grating Spectrometer. The radio emission is consistent with previously determined quiescent gyrosynchrotron properties. Multiple flares were seen with Extreme Ultraviolet Explorer, five occurring within two consecutive orbital periods. The first of these flares was <span class="hlt">observed</span> with Chandra. The Chandra <span class="hlt">observations</span> of ?2 CrB showed no systematic variations of line fluxes, widths, or Doppler shifts with orbital phase, nor any response in line width or offset due to the flare. This is consistent with both stars being equally active coronal emitters. We have developed a self-consistent method of spectral analysis to derive information from the line and continuum emissions concerning the distribution of plasma with temperature and elemental abundances. A bimodal temperature distribution is appropriate for both quiescent and flare intervals, with a stable peak at 6-8 MK and another variable enhancement at higher temperatures, with evidence for significant contribution from temperatures up to 50 MK during the flare, compared to 30 MK during quiescence. The iron abundance is subsolar during quiescence but is enriched by about a factor of 2 during a <span class="hlt">large</span> flare seen with Chandra. The noble gas elements neon and argon show elevated abundances with respect to iron, but there is no clear evidence for any first ionization potential-based abundance pattern during quiescence or the flare. We have determined coronal electron densities from the helium-like ions O VII, Ne IX, Mg XI, and Si XIII, which imply densities >=1010 cm-3. There is a small enhancement in the electron densities derived for the flare, but it is not statistically significant. We call attention to electron temperature constraints provided by the ratios of 1s2 1S0-1snp 1P1 transitions of the helium-like ions O VII, Ne IX, Mg XI, and Si XIII. The derived coronal electron pressures change by 1-2 orders of magnitude over a 25% change in temperature, implying nonisobaric coronal conditions. We find no evidence for significant departures from the effectively thin coronal assumption. The electron densities inferred from the soft X-ray spectra are inconsistent with cospatial gyrosynchrotron emission; further <span class="hlt">observations</span> are necessary to discriminate the relative locations of the radio and soft X-ray-emitting plasma.</p> <div class="credits"> <p class="dwt_author">Osten, Rachel A.; Ayres, Thomas R.; Brown, Alexander; Linsky, Jeffrey L.; Krishnamurthi, Anita</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012Sci...338.1576Q"> <span id="translatedtitle">A Particle Consistent with the Higgs Boson <span class="hlt">Observed</span> with the ATLAS Detector at the <span class="hlt">Large</span> Hadron Collider</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Nearly 50 years ago, theoretical physicists proposed that a field permeates the universe and gives energy to the vacuum. This field was required to explain why some, but not all, fundamental particles have mass. Numerous precision measurements during recent decades have provided indirect support for the existence of this field, but one crucial prediction of this theory has remained unconfirmed despite 30 years of experimental searches: the existence of a massive particle, the standard model Higgs boson. The ATLAS experiment at the <span class="hlt">Large</span> Hadron Collider at CERN has now <span class="hlt">observed</span> the production of a new particle with a mass of 126 giga-electron volts and decay signatures consistent with those expected for the Higgs particle. This result is strong support for the standard model of particle physics, including the presence of this vacuum field. The existence and properties of the newly discovered particle may also have consequences beyond the standard model itself.</p> <div class="credits"> <p class="dwt_author">ATLAS Collabortion; Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A. A.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Addy, T. N.; Adelman, J.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J. A.; Agustoni, M.; Aharrouche, M.; Ahlen, S. P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Åkesson, T. P. A.; Akimoto, G.; Akimov, A. V.; Alam, M. S.; Alam, M. A.; Albert, J.; Albrand, S.; Aleksa, M.; Aleksandrov, I. N.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Allbrooke, B. M. M.; Allport, P. P.; Allwood-Spiers, S. E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, F.; Altheimer, A.; Alvarez Gonzalez, B.; Alviggi, M. G.; Amako, K.; Amelung, C.; Ammosov, V. V.; Amor Dos Santos, S. P.; Amorim, A.; Amram, N.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Andrieux, M.-L.; Anduaga, X. S.; Angelidakis, S.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A. T. H.; Arfaoui, S.; Arguin, J.-F.; Arik, E.; Arik, M.; Armbruster, A. J.; Arnaez, O.; Arnal, V.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Ask, S.; Åsman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Atkinson, M.; Aubert, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Avolio, G.; Avramidou, R.; Axen, D.; Azuelos, G.; Azuma, Y.; Baak, M. A.; Baccaglioni, G.; Bacci, C.; Bach, A. M.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Backus Mayes, J.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D. C.; Bain, T.; Baines, J. T.; Baker, O. K.; Baker, M. D.; Baker, S.; Balek, P.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H. S.; Barak, L.; Baranov, S. P.; Barbaro Galtieri, A.; Barber, T.; Barberio, E. L.; Barberis, D.; Barbero, M.; Bardin, D. Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B. M.; Barnett, R. M.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A. E.; Bartsch, V.; Basye, A.; Bates, R. L.; Batkova, L.; Batley, J. R.; Battaglia, A.; Battistin, M.; Bauer, F.; Bawa, H. S.; Beale, S.; Beau, T.; Beauchemin, P. H.; Beccherle, R.; Bechtle, P.; Beck, H. P.; Becker, A. K.; Becker, S.; Beckingham, M.; Becks, K. H.; Beddall, A. J.; Beddall, A.; Bedikian, S.; Bednyakov, V. A.; Bee, C. P.; Beemster, L. J.; Begel, M.; Behar Harpaz, S.; Behera, P. K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P. J.; Bell, W. H.; Bella, G.; Bellagamba, L.; Bellomo, M.; Belloni, A.; Beloborodova, O.; Belotskiy, K.; Beltramello, O.; Benary, O.; Benchekroun, D.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez Garcia, J. A.; Benjamin, D. P.; Benoit, M.; Bensinger, J. R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernat, P.; Bernhard, R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Bertella, C.; Bertin, A.; Bertolucci, F.; Besana, M. I.; Besjes, G. J.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R. M.; Bianco, M.; Biebel, O.; Bieniek, S. P.; Bierwagen, K.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biscarat, C.; Bittner, B.; Black, K. M.; Blair, R. E.; Blanchard, J.-B.; Blanchot, G.; Blazek, T.; Bloch, I.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G. J.; Bobrovnikov, V. B.; Bocchetta, S. S.; Bocci, A.; Boddy, C. R.; Boehler, M.; Boek, J.; Boelaert, N.; Bogaerts, J. A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Bohm, J.; Boisvert, V.; Bold, T.; Boldea, V.; Bolnet, N. M.; Bomben, M.; Bona, M.; Boonekamp, M.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borri, M.; Borroni, S.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bozovic-Jelisavcic, I.; Bracinik, J.; Branchini, P.; Brandenburg, G. W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Brazzale, S. F.; Brelier, B.; Bremer, J.; Brendlinger, K.; Brenner, R.; Bressler, S.; Britton, D.; Brochu, F. M.; Brock, I.; Brock, R.; Broggi, F.; Bromberg, C.; Bronner, J.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brown, G.; Brown, H.; Bruckman de Renstrom, P. A.; Bruncko, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a style="font-weight: bold;">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23258888"> <span id="translatedtitle">A particle consistent with the Higgs boson <span class="hlt">observed</span> with the ATLAS detector at the <span class="hlt">Large</span> Hadron Collider.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Nearly 50 years ago, theoretical physicists proposed that a field permeates the universe and gives energy to the vacuum. This field was required to explain why some, but not all, fundamental particles have mass. Numerous precision measurements during recent decades have provided indirect support for the existence of this field, but one crucial prediction of this theory has remained unconfirmed despite 30 years of experimental searches: the existence of a massive particle, the standard model Higgs boson. The ATLAS experiment at the <span class="hlt">Large</span> Hadron Collider at CERN has now <span class="hlt">observed</span> the production of a new particle with a mass of 126 giga-electron volts and decay signatures consistent with those expected for the Higgs particle. This result is strong support for the standard model of particle physics, including the presence of this vacuum field. The existence and properties of the newly discovered particle may also have consequences beyond the standard model itself. PMID:23258888</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-21</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21266546"> <span id="translatedtitle">The <span class="hlt">observation</span> of nonlinear ion cyclotron wave excitation during high-harmonic fast wave heating in the <span class="hlt">large</span> helical device</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A wave detector, a newly designed magnetic probe, is installed in the <span class="hlt">large</span> helical device (LHD). This wave detector is a 100-turn loop coil with electrostatic shield. Comparing a one-loop coil to this detector, this detector has roughly constant power coupling in the lower frequency range of 40 MHz, and it can easily detect magnetic wave in the frequency of a few megahertz. During high-harmonic fast wave heating, lower frequency waves (<10 MHz) were <span class="hlt">observed</span> in the LHD for the first time, and for the power density threshold of lower frequency wave excitation (7.5 MHz) the power density of excited pumped wave (38.47 MHz) was approximately -46 dBm/Hz. These lower frequencies are kept constant for electron density and high energy particle distribution, and these lower frequency waves seem to be ion cyclotron waves caused by nonlinear wave-particle interaction, for example, parametric decay instability.</p> <div class="credits"> <p class="dwt_author">Kasahara, H.; Seki, T.; Kumazawa, R.; Saito, K.; Mutoh, T.; Kubo, S.; Shimozuma, T.; Igami, H.; Yoshimura, Y.; Takahashi, H.; Yamada, I.; Tokuzawa, T.; Ohdachi, S.; Morita, S.; Nomura, G.; Shimpo, F.; Komori, A.; Motojima, O. [National Institute for Fusion Science, Toki 509-5292 (Japan); Oosako, T.; Takase, Y. [Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8561 (Japan)] (and others)</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-10-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JGRD..119.7179B"> <span id="translatedtitle"><span class="hlt">Observations</span> of the refraction of microbaroms generated by <span class="hlt">large</span> maritime storms by the wind field of the generating storm</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Microbaroms are a continuous infrasonic signal in the 0.15 to 0.3 Hz band caused by the collision of oceanic surface waves of equal period. Such signals are often generated by <span class="hlt">large</span> maritime storms. Current formulation of the generation mechanism predicts that the microbarom source location due to a <span class="hlt">large</span> maritime storm in the open ocean is generally located several hundreds of kilometers from the eye of the storm. Assuming such a source location to be correct, propagation of the microbaroms along paths which pass near the storm center as well as those which propagate away from the storm structure have been examined using geometric acoustics. Microbarom propagation paths which pass near the storm center are refracted by the storm winds and are found to have back azimuths directed toward a virtual source around the storm center. Microbarom propagation paths which do not pass near the storm center are found to have back azimuths directed toward the actual source region. To validate these predictions, data from microbarom signals generated by hurricanes in the Atlantic Ocean have been collected along the east coast of the United States during the 2010 and 2011 Atlantic hurricane seasons. Data from several storm events are presented here for comparison with model predictions. In general, the <span class="hlt">observations</span> are in agreement with the predictions of the propagation model.</p> <div class="credits"> <p class="dwt_author">Blom, Philip; Waxler, Roger; Frazier, Wm. Garth; Talmadge, Carrick</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.gpo.gov:80/fdsys/pkg/FR-2011-10-06/pdf/2011-25878.pdf"> <span id="translatedtitle">76 FR 62148 - Title VI; Proposed <span class="hlt">Circular</span>, Environmental Justice; Proposed <span class="hlt">Circular</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013</a></p> <p class="result-summary">...FTA-2011-0054; Docket FTA-2011-0055] Title VI; Proposed <span class="hlt">Circular</span>, Environmental...2011, Federal Register Notices titled ``Title VI; Proposed <span class="hlt">Circular</span>'' and ``Environmental...2011, Federal Register Notices titled ``Title VI; Proposed <span class="hlt">Circular</span>'' (76 FR...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2011-10-06</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25242744"> <span id="translatedtitle">Complementary sequence-mediated exon <span class="hlt">circularization</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Exon <span class="hlt">circularization</span> has been identified from many loci in mammals, but the detailed mechanism of its biogenesis has remained elusive. By using genome-wide approaches and <span class="hlt">circular</span> RNA recapitulation, we demonstrate that exon <span class="hlt">circularization</span> is dependent on flanking intronic complementary sequences. Such sequences and their distribution exhibit rapid evolutionary changes, showing that exon <span class="hlt">circularization</span> is evolutionarily dynamic. Strikingly, exon <span class="hlt">circularization</span> efficiency can be regulated by competition between RNA pairing across flanking introns or within individual introns. Importantly, alternative formation of inverted repeated Alu pairs and the competition between them can lead to alternative <span class="hlt">circularization</span>, resulting in multiple <span class="hlt">circular</span> RNA transcripts produced from a single gene. Collectively, exon <span class="hlt">circularization</span> mediated by complementary sequences in human introns and the potential to generate alternative <span class="hlt">circularization</span> products extend the complexity of mammalian posttranscriptional regulation. PMID:25242744</p> <div class="credits"> <p class="dwt_author">Zhang, Xiao-Ou; Wang, Hai-Bin; Zhang, Yang; Lu, Xuhua; Chen, Ling-Ling; Yang, Li</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-25</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JQSRT.131...59N"> <span id="translatedtitle">Characterization and remote sensing of biological particles using <span class="hlt">circular</span> polarization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Biological molecules are characterized by an intrinsic asymmetry known as homochirality. The result is optical activity of biological materials and <span class="hlt">circular</span> polarization in the light scattered by microorganisms, cells of living organisms, as well as molecules (e.g. amino acids) of biological origin. Lab measurements (Sparks et al. (2009) [6,7]) have found that light scattered by certain biological systems, in particular photosynthetic organisms, is not only <span class="hlt">circular</span> polarized but contains a characteristic spectral trend, showing a fast change and reversal of sign for <span class="hlt">circular</span> polarization within absorption bands. Similar behavior can be expected for other biological and prebiological organics, especially amino acids. We begin our study by reproducing the laboratory measurements for photosynthetic organisms through modeling the biological material as aggregated structures and using the Multiple Sphere T-matrix (MSTM) code for light scattering calculations. We further study how the spectral effect described above depends on the porosity of the aggregates and the size and number of the constituent particles (monomers). We show that larger aggregates are characterized by larger values of <span class="hlt">circular</span> polarization and discuss how light-scattering characteristics of individual monomers and electromagnetic interaction between them affect this result. We find that <span class="hlt">circular</span> polarization typically peaks at medium (40-140°) scattering angles, and discuss recommendations for efficient remote <span class="hlt">observation</span> of <span class="hlt">circular</span> polarization from (pre)biological systems.</p> <div class="credits"> <p class="dwt_author">Nagdimunov, Lev; Kolokolova, Ludmilla; Mackowski, Daniel</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/astro-ph/0505114v1"> <span id="translatedtitle"><span class="hlt">Large</span>-Scale Sidereal Anisotropy of Galactic Cosmic-Ray Intensity <span class="hlt">Observed</span> by the Tibet Air Shower Array</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We present the <span class="hlt">large</span>-scale sidereal anisotropy ofgalactic cosmic-ray intensity in the multi-TeV region <span class="hlt">observed</span> with the Tibet-IIIair shower array during the period from 1999 through 2003. The sidereal daily variation of cosmic rays <span class="hlt">observed</span> in this experiment shows an excess of relative intensity around $4\\sim7 $ hours local sidereal time, as well as a deficit around 12 hours local sidereal time. While the amplitude of the excess is not significant when averaged over all declinations, the excess in individual declinaton bands becomes larger and clearer as the viewing direction moves toward the south. The maximum phase of the excess intensity changes from $\\sim$7 at the northern hemisphere to $\\sim$4 hours at the equatorial region. We also show that both the amplitude and the phase of the first harmonic vector of the daily variation are remarkably independent of primary energy in the multi-TeV region. This is the first result determining the energy and declination dependences of the full 24-hour profiles of the sidereal daily variation in the multi-TeV region with a single air shower experiment.</p> <div class="credits"> <p class="dwt_author">The Tibet AS Gamma Collaboration; M. Amenomori</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-06</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014SPIE.9202E..1EM"> <span id="translatedtitle"><span class="hlt">Circular</span> polarized leaky wave surface</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A <span class="hlt">circular</span> polarized (CP) infrared (IR) leaky wave surface design is presented. The metasurface consists of an array of rectangular patches connected by microstrip and operating over the long-wave infrared (LWIR) spectrum with directional wave emission and absorption. The surface is composed of periodically aligned arrays of sub-wavelength metal patches separated from a ground plane by a dielectric slab. The design combines the features of the conventional patch and leaky wave antenna leading to a metasurface that preferentially emits CP IR radiation by use of axial asymmetrical unit cells. This is a deviation from reported structures that mainly employ a phase shifter to combine linearly polarized waves in order to attain <span class="hlt">circular</span> polarization. The performance of this leaky wave surface is verified through full-wave simulation using the ANSYS HFSS finite element analysis tool. The leaky wave phenomenon is demonstrated by the frequency and angular dependence of the absorption while <span class="hlt">circular</span> polarization is characterized via stokes parameters. The main beam of this surface can be steered continuously by varying the frequency while maintaining <span class="hlt">circular</span> polarization within the main beam direction. A CP leaky wave at 10.6 ?m with a scanning angle of 30° is demonstrated. Metasurfaces exhibiting spectral and polarization selectivity in absorption/emission hold the potential for impact in IR applications including detection, imaging, thermal management, energy harvesting and tagging.</p> <div class="credits"> <p class="dwt_author">Manene, Franklin; Lail, Brian A.; Kinzel, Edward C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFMIN53B0825Y"> <span id="translatedtitle">Development of the <span class="hlt">Large</span>-Scale Statistical Analysis System of Satellites <span class="hlt">Observations</span> Data with Grid Datafarm Architecture</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the Solar-Terrestrial Physics (STP) field, the amount of satellite <span class="hlt">observation</span> data has been increasing every year. It is necessary to solve the following three problems to achieve <span class="hlt">large</span>-scale statistical analyses of plenty of data. (i) More CPU power and larger memory and disk size are required. However, total powers of personal computers are not enough to analyze such amount of data. Super-computers provide a high performance CPU and rich memory area, but they are usually separated from the Internet or connected only for the purpose of programming or data file transfer. (ii) Most of the <span class="hlt">observation</span> data files are managed at distributed data sites over the Internet. Users have to know where the data files are located. (iii) Since no common data format in the STP field is available now, users have to prepare reading program for each data by themselves. To overcome the problems (i) and (ii), we constructed a parallel and distributed data analysis environment based on the Gfarm reference implementation of the Grid Datafarm architecture. The Gfarm shares both computational resources and perform parallel distributed processings. In addition, the Gfarm provides the Gfarm filesystem which can be as virtual directory tree among nodes. The Gfarm environment is composed of three parts; a metadata server to manage distributed files information, filesystem nodes to provide computational resources and a client to throw a job into metadata server and manages data processing schedulings. In the present study, both data files and data processes are parallelized on the Gfarm with 6 file system nodes: CPU clock frequency of each node is Pentium V 1GHz, 256MB memory and40GB disk. To evaluate performances of the present Gfarm system, we scanned plenty of data files, the size of which is about 300MB for each, in three processing methods: sequential processing in one node, sequential processing by each node and parallel processing by each node. As a result, in comparison between the number of files and the elapsed time, parallel and distributed processing shorten the elapsed time to 1/5 than sequential processing. On the other hand, sequential processing times were shortened in another experiment, whose file size is smaller than 100KB. In this case, the elapsed time to scan one file is within one second. It implies that disk swap took place in case of parallel processing by each node. We note that the operation became unstable when the number of the files exceeded 1000. To overcome the problem (iii), we developed an original data class. This class supports our reading of data files with various data formats since it converts them into an original data format since it defines schemata for every type of data and encapsulates the structure of data files. In addition, since this class provides a function of time re-sampling, users can easily convert multiple data (array) with different time resolution into the same time resolution array. Finally, using the Gfarm, we achieved a high performance environment for <span class="hlt">large</span>-scale statistical data analyses. It should be noted that the present method is effective only when one data file size is <span class="hlt">large</span> enough. At present, we are restructuring the new Gfarm environment with 8 nodes: CPU is Athlon 64 x2 Dual Core 2GHz, 2GB memory and 1.2TB disk (using RAID0) for each node. Our original class is to be implemented on the new Gfarm environment. In the present talk, we show the latest results with applying the present system for data analyses with huge number of satellite <span class="hlt">observation</span> data files.</p> <div class="credits"> <p class="dwt_author">Yamamoto, K.; Murata, K.; Kimura, E.; Honda, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009A%26A...495..869L"> <span id="translatedtitle"><span class="hlt">Large</span> grains in discs around young stars: ATCA <span class="hlt">observations</span> of WW Chamaeleontis, RU Lupi, and CS Chamaeleontis</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Context: Grains in discs around young stars grow from interstellar submicron sizes to planetesimals, up to thousands of kilometres in size, over the course of several Myr. Thermal emission of <span class="hlt">large</span> grains or pebbles can be best <span class="hlt">observed</span> at centimetre wavelengths. However, other emission mechanisms can contribute, most notably free-free emission from stellar winds and chromospheric activity. Aims: We aim to determine the mechanisms of centimetre emission for three T Tauri stars. WW Cha and RU Lup have recently been found to have grain growth at least up to millimetre sizes in their circumstellar discs, based on millimetre data up to 3.3 mm. CS Cha has similar indications of grain growth in its circumbinary disc. Methods: The T Tauri stars WW Cha and RU Lup were monitored over the course of several years at millimetre and centimetre wavelengths, using the Australia Telescope Compact Array (ATCA). The new ATCA 7 mm system was also used to <span class="hlt">observe</span> CS Cha at 7 mm. Results: WW Cha was detected on several occasions at 7 and 16 mm. We obtained one detection of WW Cha at 3.5 cm and upper limits only for 6.3 cm. The emission at 16 mm was stable over periods of days, months, and years, whereas the emission at 3.5 cm is found to be variable. A second young stellar object, Ced 112 IRS 4, was found in the field of WW Cha at 16 mm. RU Lup was detected at 7 mm. It was <span class="hlt">observed</span> at 16 mm three times and at 3 and 6 cm four times and found to be variable in all three wavebands. CS Cha was detected at 7 mm, but the signal-to-noise ratio was not high enough to resolve the gap in the circumbinary disc. The typical resolution of the 7 and 16 mm <span class="hlt">observations</span> was 5-10 arcsec with rms ~0.2 mJy. Conclusions: The emission at 3, 7, and 16 mm for WW Cha is explained well by thermal emission from millimetre and centimetre-sized “pebbles”. The cm spectral index between 3.5 and 6.3 cm is consistent with the emission from an optically-thick ionised wind, although the high variability of the cm emission points to a non-thermal contribution. The spectral energy distributions of both RU Lup and CS Cha from 1 to 7 mm are consistent with thermal emission from mm-sized grains. The variability of the longer-wavelength emission for RU Lup and the negative spectral index suggests non-thermal emission, arising from an optically-thin plasma.</p> <div class="credits"> <p class="dwt_author">Lommen, D.; Maddison, S. T.; Wright, C. M.; van Dishoeck, E. F.; Wilner, D. J.; Bourke, T. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18662233"> <span id="translatedtitle">Mode shapes and stress-resultants of <span class="hlt">circular</span> Mindlin plates with free edges</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Presented herein are exact vibration mode shapes and modal stress-resultants for freely vibrating, <span class="hlt">circular</span> Mindlin plates with free edges. These documented solutions are important in the hydroelastic analysis of very <span class="hlt">large</span> <span class="hlt">circular</span> floating structures (VLFS) which are commonly modeled as plates with free edges. The exact vibration solutions will enable engineers to obtain a very accurate set of deflections and</p> <div class="credits"> <p class="dwt_author">C. M Wang; Y. Xiang; E. Watanabe; T. Utsunomiya</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/6512832"> <span id="translatedtitle">Modeling and Experiment Evaluation of <span class="hlt">Circular</span> Polyacrylate Dielectric Elastomer Actuation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Dielectric elastomer (DE) is a type of electroactive polymer with <span class="hlt">large</span> strain, fast response and high efficiency, and is thought to be a promising actuation and sensing material for new device and structure. Three strain energy forms are studied for DE actuation modeling. Also, uniaxial extension experiment and plane <span class="hlt">circular</span> actuator actuation experiment were performed based on polyacrylate dielectric elastomer</p> <div class="credits"> <p class="dwt_author">Xinmei Qi; Shousen Zheng; Juan Chen</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004EL.....68..797G"> <span id="translatedtitle">Imaging surface photonic states with a <span class="hlt">circularly</span> polarized tip</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Photon unoccupied states tailored by nanostructures present at sample surfaces can be probed using a scanning near-field optical microscope including <span class="hlt">large</span> detection angles (Chicanne C. et al., Phys. Rev. Lett., 88 (2002) 097402-4). We demonstrate, theoretically and experimentally, how such setups equipped with a <span class="hlt">circularly</span> polarized SNOM tip can deliver images of surface photonic states with a nanometer scale resolution.</p> <div class="credits"> <p class="dwt_author">Girard, Ch.; David, T.; Chicanne, C.; Mary, A.; Colas des Francs, G.; Bourillot, E.; Weeber, J.-C.; Dereux, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/45479057"> <span id="translatedtitle">Self-Destabilizing Mechanism of <span class="hlt">Circular</span> Liquid Jet</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Disintegration mechanism through a liquid-phase feedback loop is explored for a <span class="hlt">circular</span> liquid jet issued into an otherwise quiescent gas. An asymptotic analysis of capillary waves radiating from the liquid jet tip is used to derive analytical expression for the feed back loop for the regular axisymmetric liquid jet disintegration occurring at a <span class="hlt">large</span> distance from the nozzle exit for</p> <div class="credits"> <p class="dwt_author">Akira Umemura</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.C33A0657C"> <span id="translatedtitle">Temporal trends in West Antarctic surface mass balance: do <span class="hlt">large</span> scale modes of climate contribute to <span class="hlt">observed</span> records?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Western Antarctica has been warming significantly at a rate of 0.17× 0.06 degrees C per decade from 1957 to 2006, with the strongest warming in the winter and spring months. Annual accumulation rates in the central WAIS have been decreasing over the same time period, in spite of rising temperatures. This is somewhat unexpected, as saturation vapor pressure increases with increasing temperature. One possible explanation of this <span class="hlt">observation</span> could be related to synoptic-scale modes of climate, principally the Southern Annular Mode (SAM) and the El Nino Southern Oscillation (ENSO). These modes of climate are known to modify the track and strength of storms seasonally, but the true extent of the influence of these modes on accumulation in central WAIS is not well known. This is due, in part, to sparse instrumental weather data which makes it difficult to understand the spatial and temporal variability of the central WAIS Surface Mass Balance (SMB). Firn cores provide an excellent temporal SMB record that can fill this data gap, but are spatially limited. The spatial limitation of individual cores can be remedied by creating a network of firn cores over a region, which overcomes small scale variability and provides a regional representation of SMB over the temporal length of the firn core records. The 2011 Satellite Era Accumulation Traverse (SEAT) adds nine new firn cores (20 m deep, spanning 2010-1981) to existing cores within the same region of the central WAIS to improve the spatial network of regional SMB measurements. SMB is reconstructed from the firn cores, and are compared to simulated accumulation from five climate models and reanalyses datasets. The combination of firn cores and simulated records are used to investigate wether SAM and ENSO significantly influence SMB in the central WAIS. The new suite of cores show a statistically significant negative trend in accumulation during the past three decades, which is consistent with results from the previous cores. These trends represent a negative region-wide SMB trend that is likely connected to <span class="hlt">large</span> scale modes of climate, possibly associated with tropical Pacific climate variability. All five of the modeled SMB datasets show anomalous accumulation during anomalous phases of SAM and ENSO, although not all of these anomalies are significant at the 95% confidence level. These simulated results are compared to composite analysis of the firn core data over the same region to assess the validity of the model results. Understanding how <span class="hlt">large</span> scale modes of climate contribute to the trends <span class="hlt">observed</span> from the firn core records will help reconstruct past and predict future changes in the central WAIS SMB.</p> <div class="credits"> <p class="dwt_author">Carpenter, M.; Rupper, S.; Williams, J.; Burgener, L. K.; Koenig, L.; Forster, R. R.; Koutnik, M. R.; Skinner, R.; Miege, C.; Brucker, L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013aoel.confE..58O"> <span id="translatedtitle">Analysis of fratricide effect <span class="hlt">observed</span> with GeMS and its relevance for <span class="hlt">large</span> aperture astronomical telescopes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Large</span> aperture ground-based telescopes require Adaptive Optics (AO) to correct for the distortions induced by atmospheric turbulence and achieve diffraction limited imaging quality. These AO systems rely on Natural and Laser Guide Stars (NGS and LGS) to provide the information required to measure the wavefront from the astronomical sources under <span class="hlt">observation</span>. In particular one such LGS method consists in creating an artificial star by means of fluorescence of the sodium atoms at the altitude of the Earth's mesosphere. This is achieved by propagating one or more lasers, at the wavelength of the Na D2a resonance, from the telescope up to the mesosphere. Lasers can be launched from either behind the secondary mirror or from the perimeter of the main aperture. The so-called central- and side-launch systems, respectively. The central-launch system, while helpful to reduce the LGS spot elongation, introduces the so-called "fratricide" effect. This consists of an increase in the photon-noise in the AO Wave Front Sensors (WFS) sub-apertures, with photons that are the result of laser photons back-scattering from atmospheric molecules (Rayleigh scattering) and atmospheric aerosols (dust and/or cirrus clouds ice particles). This affects the performance of the algorithms intended to compute the LGS centroids and subsequently compute and correct the turbulence-induced wavefront distortions. In the frame of the Thirty Meter Telescope (TMT) project and using actual LGS WFS data obtained with the Gemini Multi-Conjugate Adaptive Optics System (Gemini MCAO a.k.a. GeMS), we show results from an analysis of the temporal variability of the <span class="hlt">observed</span> fratricide effect, as well as comparison of the absolute magnitude of fratricide photon-flux level with simulations using models that account for molecular (Rayleigh) scattering and photons backscattered from cirrus clouds.</p> <div class="credits"> <p class="dwt_author">Otarola, Angel; Neichel, Benoit; Wang, Lianqi; Boyer, Corinne; Ellerbroek, Brent; Rigaut, François</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21576658"> <span id="translatedtitle"><span class="hlt">OBSERVATIONS</span> OF THE YOUNG SUPERNOVA REMNANT RX J1713.7-3946 WITH THE FERMI <span class="hlt">LARGE</span> AREA TELESCOPE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present <span class="hlt">observations</span> of the young supernova remnant (SNR) RX J1713.7-3946 with the Fermi <span class="hlt">Large</span> Area Telescope (LAT). We clearly detect a source positionally coincident with the SNR. The source is extended with a best-fit extension of 0.{sup 0}55 {+-} 0.{sup 0}04 matching the size of the non-thermal X-ray and TeV gamma-ray emission from the remnant. The positional coincidence and the matching extended emission allow us to identify the LAT source with SNR RX J1713.7-3946. The spectrum of the source can be described by a very hard power law with a photon index of {Gamma} = 1.5 {+-} 0.1 that coincides in normalization with the steeper H.E.S.S.-detected gamma-ray spectrum at higher energies. The broadband gamma-ray emission is consistent with a leptonic origin as the dominant mechanism for the gamma-ray emission.</p> <div class="credits"> <p class="dwt_author">Abdo, A. A. [Center for Earth Observing and Space Research, College of Science, George Mason University, Fairfax, VA 22030 (United States); Ackermann, M.; Ajello, M.; Allafort, A.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Baldini, L.; Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Baring, M. G. [Department of Physics and Astronomy, Rice University, Houston, TX 77251 (United States); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Bouvier, A. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Brandt, T. J. [CNRS, IRAP, F-31028 Toulouse cedex 4 (France); Brigida, M. [Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P., E-mail: markusa@slac.stanford.edu, E-mail: funk@slac.stanford.edu, E-mail: uchiyama@slac.stanford.edu [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/1002566"> <span id="translatedtitle"><span class="hlt">Large</span> volume collapse <span class="hlt">observed</span> in the phase transition in cubic PbCrO[subscript 3] perovskite</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">When cubic PbCrO{sub 3} perovskite (Phase I) is squeezed up to {approx}1.6 GPa at room temperature, a previously undetected phase (Phase II) has been <span class="hlt">observed</span> with a 9.8% volume collapse. Because the structure of Phase II can also be indexed into a cubic perovskite as Phase I, the transition between Phases I and II is a cubic to cubic isostructural transition. Such a transition appears independent of the raw materials and synthesizing methods used for the cubic PbCrO{sub 3} perovskite sample. In contrast to the high-pressure isostructural electronic transition that appears in Ce and SmS, this transition seems not related with any change of electronic state, but it could be possibly related on the abnormally <span class="hlt">large</span> volume and compressibility of the PbCrO{sub 3} Phase I. The physical mechanism behind this transition and the structural and electronic/magnetic properties of the condensed phases are the interesting issues for future studies.</p> <div class="credits"> <p class="dwt_author">Xiao, Wansheng; Tan, Dayong; Xiong, Xiaolin; Liu, Jing; Xu, Jian (Chinese Aca. Sci.)</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-08-27</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20130011727&hterms=Carson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DC%2BCarson"> <span id="translatedtitle">Polarimetric Imaging of <span class="hlt">Large</span> Cavity Structures in the Pre-transitional Protoplanetary Disk Around PDS 70: <span class="hlt">Observations</span> of the Disk</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We present high resolution H-band polarized intensity (PI; FWHM = 0."1: 14 AU) and L'-band imaging data (FWHM = 0."11: 15 AU) of the circumstellar disk around the weak-lined T Tauri star PDS 70 in Centaurus at a radial distance of 28 AU (0."2) up to 210 AU (1."5). In both images, a giant inner gap is clearly resolved for the first time, and the radius of the gap is approx.70 AU. Our data show that the geometric center of the disk shifts by approx.6 AU toward the minor axis. We confirm that the brown dwarf companion candidate to the north of PDS 70 is a background star based on its proper motion. As a result of SED fitting by Monte Carlo radiative transfer modeling, we infer the existence of an optically thick inner disk at a few AU. Combining our <span class="hlt">observations</span> and modeling, we classify the disk of PDS 70 as a pre-transitional disk. Furthermore, based on the analysis of L'-band imaging data, we put an upper limit mass of companions at approx.30 to approx.50MJ within the gap. Taking account of the presence of the <span class="hlt">large</span> and sharp gap, we suggest that the gap could be formed by dynamical interactions of sub-stellar companions or multiple unseen giant planets in the gap. Subject headings: planetary systems - protoplanetary disks - stars: individual (PDS 70) - stars: pre-main sequence - polarization</p> <div class="credits"> <p class="dwt_author">Hashimoto, J.; Dong, R.; Kudo, T.; Honda, M.; Zhu, Z.; McClure, M. K.; Muto, T.; Wisniewski, J.; Abe, L.; Brandner, W.; Brandt, T.; Carson, J.; Egner, S.; Feldt, M.; Fukagawa, M.; Goto, M.; Grady, C. A.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K.; Ishii, M.; Iye, M.; Janson, M.; Kandori, R.; Knapp, G.; Kusakabe, N.; Kuzuhara, M.; Kwon, J.; Matsuo, T.; Mayama, S.; McElwain, M. W.; Serabyn, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/10642194"> <span id="translatedtitle">Hubble Space Telescope and Very <span class="hlt">Large</span> Array <span class="hlt">Observations</span> of the H2O Gigamaser Galaxy TXS 2226-184.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present Hubble Space Telescope/Wide-Field and Planetary Camera 2 images in Halpha + [N ii] lambdalambda6548, 6583 lines and continuum radiation and a VLA map at 8 GHz of the H2O gigamaser galaxy TXS 2226-184. This galaxy has the most luminous H2O maser emission known to date. Our red continuum images reveal a highly elongated galaxy with a dust lane crossing the nucleus. The surface brightness profile is best fitted by a bulge plus exponential disk model, favoring classification as a highly inclined spiral galaxy (i=70&j0;). The color map confirms that the dust lane is aligned with the galaxy major axis and is crossing the putative nucleus. The Halpha + [N ii] map exhibits a gaseous, jetlike structure perpendicular to the nuclear dust lane and the galaxy major axis. The radio map shows compact, steep spectrum emission that is elongated in the same direction as the Halpha + [N ii] emission. By analogy with Seyfert galaxies, we therefore suspect that this alignment reflects an interaction between the radio jet and the interstellar medium. The axes of the nuclear dust disk, the radio emission, and the optical line emission apparently define the axis of the active galactic nucleus. The <span class="hlt">observations</span> suggest that in this galaxy the nuclear accretion disk, obscuring torus, and <span class="hlt">large</span>-scale molecular gas layer are roughly coplanar. Our classification of the host galaxy strengthens the trend for megamasers to be found preferentially in highly inclined spiral galaxies. PMID:10642194</p> <div class="credits"> <p class="dwt_author">Falcke; Wilson; Henkel; Brunthaler; Braatz</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-02-10</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a 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href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a style="font-weight: bold;">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_20");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22078497"> <span id="translatedtitle">POLARIMETRIC IMAGING OF <span class="hlt">LARGE</span> CAVITY STRUCTURES IN THE PRE-TRANSITIONAL PROTOPLANETARY DISK AROUND PDS 70: <span class="hlt">OBSERVATIONS</span> OF THE DISK</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present high-resolution H-band polarized intensity (FWHM = 0.''1: 14 AU) and L'-band imaging data (FWHM = 0.''11: 15 AU) of the circumstellar disk around the weak-lined T Tauri star PDS 70 in Centaurus at a radial distance of 28 AU (0.''2) up to 210 AU (1.''5). In both images, a giant inner gap is clearly resolved for the first time, and the radius of the gap is {approx}70 AU. Our data show that the geometric center of the disk shifts by {approx}6 AU toward the minor axis. We confirm that the brown dwarf companion candidate to the north of PDS 70 is a background star based on its proper motion. As a result of spectral energy distribution fitting by Monte Carlo radiative transfer modeling, we infer the existence of an optically thick inner disk at a few AU. Combining our <span class="hlt">observations</span> and modeling, we classify the disk of PDS 70 as a pre-transitional disk. Furthermore, based on the analysis of L'-band imaging data, we put an upper limit of {approx}30 to {approx}50 M{sub J} on the mass of companions within the gap. Taking into account the presence of the <span class="hlt">large</span> and sharp gap, we suggest that the gap could be formed by dynamical interactions of sub-stellar companions or multiple unseen giant planets in the gap.</p> <div class="credits"> <p class="dwt_author">Hashimoto, J.; Hayashi, M. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Dong, R.; Zhu, Z.; Brandt, T. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Kudo, T.; Egner, S.; Guyon, O.; Hayano, Y. [Subaru Telescope, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Honda, M. [Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); McClure, M. K. [Department of Astronomy, University of Michigan, 500 Church Street, 830 Dennison Building, Ann Arbor, MI 48109 (United States); Muto, T. [Division of Liberal Arts, Kogakuin University, 1-24-2, Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677 (Japan); Wisniewski, J. [University of Washington, Seattle, WA 98195 (United States); Abe, L. [Laboratoire Hippolyte Fizeau, UMR6525, Universite de Nice Sophia-Antipolis, 28, avenue Valrose, F-06108 Nice Cedex 02 (France); Brandner, W.; Carson, J.; Feldt, M. [Max Planck Institute for Astronomy, D-69117 Heidelberg (Germany); Fukagawa, M. [Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Goto, M. [Universitaets-Sternwarte Muenchen, Scheinerstr. 1, D-81679 Munich (Germany); Grady, C. A., E-mail: jun.hashimoto@nao.ac.jp [Exoplanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); and others</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/1563932"> <span id="translatedtitle">Lupus I <span class="hlt">Observations</span> from the 2010 Flight of the Balloon-borne <span class="hlt">Large</span> Aperture Submillimeter Telescope for Polarimetry</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">The Balloon-borne <span class="hlt">Large</span> Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was created by adding polarimetric capability to the BLAST experiment that was flown in 2003, 2005, and 2006. BLASTPol inherited BLAST's 1.8 m primary and its Herschel/SPIRE heritage focal plane that allows simultaneous <span class="hlt">observation</span> at 250, 350, and 500 {\\mu}m. We flew BLASTPol in 2010 and again in 2012. Both were long duration Antarctic flights. Here we present polarimetry of the nearby filamentary dark cloud Lupus I obtained during the 2010 flight. Despite limitations imposed by the effects of a damaged optical component, we were able to clearly detect submillimeter polarization on degree scales. We compare the resulting BLASTPol magnetic field map with a similar map made via optical polarimetry (The optical data were published in 1998 by J. Rizzo and collaborators.). The two maps partially overlap and are reasonably consistent with one another. We compare these magnetic field maps to the orientations of filaments in Lupus I,...</p> <div class="credits"> <p class="dwt_author">Matthews, Tristan G; Angilè, Francesco E; Benton, Steven J; Chapin, Edward L; Chapman, Nicholas L; Devlin, Mark J; Fissel, Laura M; Fukui, Yasuo; Gandilo, Natalie N; Gundersen, Joshua O; Hargrave, Peter C; Klein, Jeffrey; Korotkov, Andrei L; Moncelsi, Lorenzo; Mroczkowski, Tony K; Netterfield, Calvin B; Novak, Giles; Nutter, David; Olmi, Luca; Pascale, Enzo; Poidevin, Frédérick; Savini, Giorgio; Scott, Douglas; Shariff, Jamil A; Soler, Juan Diego; Tachihara, Kengo; Thomas, Nicholas E; Truch, Matthew D P; Tucker, Carole E; Tucker, Gregory S; Ward-Thompson, Derek</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://cdsweb.cern.ch/record/437220"> <span id="translatedtitle">Suppression of Supercontinuum Generation with <span class="hlt">Circularly</span> Polarized Light</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">Controlling a nonlinear process like supercontinuum generation (SG) with the polarization-state of laser is an important demonstration of laser selectivity. We show that the threshold for SG and the total amount of supercontinuum generated depends on incident laser polarization for isotropic samples. Irrespective of the nature of the samples chosen, SG efficiency decreases as the incident laser polarization changes from linear to <span class="hlt">circular</span> and thus, provides the first experimental demonstration of the suppression of SG with <span class="hlt">circularly</span> polarized light. The ratio of the overall SG between the linear and <span class="hlt">circular</span> polarization (i.e., measure of suppression) undergoes an intensity dependent decrease from <span class="hlt">large</span> initial values to asymptotic limits, irrespective of samples.</p> <div class="credits"> <p class="dwt_author">Singh-Sandhu, A; Goswami, D Y; Sandhu, Arvinder S.; Banerjee, Sudeep; Goswami, Debabrata</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/S0141-1136(02)00328-8"> <span id="translatedtitle"><span class="hlt">Observations</span> of <span class="hlt">large</span>-amplitude cross-shore internal bores near the shelf break, Santa Monica Bay, CA</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Two sets of moorings were deployed along a cross-shelf transect in central Santa Monica bay for four months in the winter of 1998-1999. Both sites had an array of instruments attached to tripods set on the seafloor to monitor currents over the entire water column, surface waves, near-bed temperature, water clarity and suspended sediment. A companion mooring had temperature sensors spaced approximately 10 m apart to measure temperature profiles between the surface and the seafloor. One array was deployed in 70 m of water at a site adjacent to the shelf break, just northwest of a major ocean outfall. The other was deployed on the mid shelf in 35 m of water approximately 6 km from the shelf break site. The subtidal currents in the region flowed parallel to the isobaths with fluctuating time scales around 10 days, a typical coastal-ocean pattern. However, during the falling phase of the barotropic spring tide, sets of <span class="hlt">large</span>-amplitude, sheared cross-shore current pulses with a duration of 2-5 h were <span class="hlt">observed</span> at the shelf break site. Currents in these pulses flowed exclusively offshore in a thin layer near the bed with amplitudes reaching 30-40 cm/s. Simultaneously, currents with amplitudes around 15-20 cm/s flowed exclusively onshore in the thicker layer between the offshore flow layer and the sea surface. The net offshore transport was about half the onshore transport. Near-surface isotherms were depressed 30-40 m. These pulses were likely internal bores generated by tidal currents. Bed stresses associated with these events exceeded 3 dynes/cm2. These amplitudes are <span class="hlt">large</span> enough to resuspend and transport not only fine-grained material, but also medium to coarse sands from the shelf toward the slope. Consequently, the seafloor over the shelf break was swept clear of fine sediments. The data suggest that the internal bores dissipate and are reduced in amplitude as they propagate across this relatively narrow shelf. There is evidence that they reach the 35 m site, but other coastal ocean processes obscure their distinctive characteristics.</p> <div class="credits"> <p class="dwt_author">Noble, M. A.; Xu, J. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000ApJ...544.1141S"> <span id="translatedtitle">Anomalous <span class="hlt">Circular</span> Polarization Profiles in Sunspot Chromospheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper presents a detailed description, analysis, and interpretation of the spectropolarimetric <span class="hlt">observations</span> recently reported by Socas-Navarro, Trujillo Bueno, & Ruiz Cobo. These <span class="hlt">observations</span> consist of time series of Stokes I and V profiles above a sunspot umbra. The spectral lines <span class="hlt">observed</span> simultaneously are the Ca II chromospheric lines at 8498 and 8542 Å and the photospheric Fe I line at 8497 Å. These spectropolarimetric <span class="hlt">observations</span> unveil an intriguing time-dependent behavior of the Stokes V profiles in the chromospheric lines. This behavior should be considered as an <span class="hlt">observational</span> reference for future radiation magnetohydrodynamic simulations of sunspot chromospheres. The analysis of the <span class="hlt">observed</span> time series shows that a ``normal,'' nearly antisymmetric V profile rapidly evolves toward an ``anomalous,'' completely asymmetric profile, returning later to the normal state. The occurrence of such anomalous <span class="hlt">circular</span> polarization profiles repeats itself with a periodicity of ~150 s. After giving arguments to discard other scenarios, we are able to interpret the anomalous V profiles as a consequence of the development of a second unresolved atmospheric component. This unresolved component seems to be the same that produces the umbral flashes <span class="hlt">observed</span> in other sunspots, where it is present with a larger filling factor. Based on <span class="hlt">observations</span> obtained with the Gregory Coudé Telescope, operated on the island of Tenerife by the Observatory of Göttingen University, in the Spanish Observatorio del Teide of the Instituto de Astrofísica de Canarias.</p> <div class="credits"> <p class="dwt_author">Socas-Navarro, H.; Trujillo Bueno, J.; Ruiz Cobo, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.P53A2062K"> <span id="translatedtitle">Evidence from Impact Crater <span class="hlt">Observations</span> for Few <span class="hlt">Large</span> Impacts on the Moon 0.8-1.7 Ga</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Our Moon is a keystone for understanding the inner solar system impact flux through time, because it is the only body for which we have crater size-frequency distributions (SFDs) through most of bombardment history and radiometric ages of probable associated terrains. Even so, the bombardment rate over the last 3.5 Gyr is poorly understood. According to the spatial density of sub-km craters on dated lunar terrains, the lunar impact flux has been roughly constant over this interval [e.g., 1 and references therein]. If so, one may expect that craters with diameter (D) > 50 km should also be equally dispersed in time over the last 3.5 Gyr. Surprisingly, our new work indicates this may not be so. We have compiled SFDs for small, superposed craters with D~0.6-15 km on the original floors of several previously designated Copernican and Eratothenian craters (USGS Geological Atlas of the Moon and [2]) with D > 50 km using JMARS. Using these data we compute the <span class="hlt">large</span> craters' formation model ages with the Model Production Function chronology developed by Marchi et al. [3]. Many of these craters, especially on the farside (e.g., Sharnov, Birkeland), can now be suitably examined only because of the excellent LROC imaging (we use the Wide Angle Camera mosaic). As a test of our methods, we calculated the model age of the 55 km crater Aristillus (34°N, 1°E), a relatively young crater thought to have showered the Apollo 15 landing site with ejecta. Interestingly, our model age of 2.2 ± 0.6 Ga is surprisingly consistent with a 2.1 Ga-old impact-derived clast (radiometric age) returned by the Apollo 15 astronauts [4]. We find that nearly all of our computed ages for the <span class="hlt">large</span> craters are older than indicated by previous work, with very few having ages younger than 3 Ga. Reasons for these discrepancies include (i) use of poor resolution Lunar Orbiter images (especially away from the near side) and (ii) application of the unreliable "DL" method, which involves simplified assumptions about how craters degrade. In addition, when our crater ages are combined with others determined (e.g., Copernicus, Tycho, King; [5-9]), we preliminarily <span class="hlt">observe</span> a relative lull in lunar impact cratering for ~0.8-1.7 Ga. Intriguingly, this interval appears to roughly coincide with a period on Earth called the "boring billion" [10], when the evolution of life appears to have been stagnant and oceans were euxinic (poorly mixed, <span class="hlt">largely</span> starved of oxygen). We speculate that absence of major terrestrial impacts may have surprising implications for the history of life and our biosphere. References: [1] Neukum, G., et al. (2001) SSR 96, 55-86. [2] Wilhelms, D.E. (1987) Geologic History of the Moon USGS, Paper 1348. [3] Marchi, S., et al. (2009) AJ 137, 4936-4948. [4] Ryder, G., et al. (1991) Geology 19, 143-146. [5] Neukum, G. and B. König (1976). Lunar Sci. VII. Proc., 2867-2881. [6] Hiesinger, H., et al. (2012) JGR 117, E00H10, doi: 10.1029/2011je003935. [7] van der Bogert, C.H., et al. (2010). LPSC XLI. Abst. #2165. [8] McEwen, A.S., et al. (1993) JGR 98, 17207-17231. [9] Ashley, J.W., et al. (2011). 42nd LPSC, Abst. #2437. [10] Holland, H.D. (2006) Phil. Trans. R. Soc. B 361, 903-915.</p> <div class="credits"> <p class="dwt_author">Kirchoff, M. R.; Bottke, W. F.; Marchi, S.; Chapman, C. R.; Enke, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/6312109"> <span id="translatedtitle">Asymptotic stability boundaries of ballooning modes in <span class="hlt">circular</span> tokamaks</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The model ballooning mode equation of Connor, Hastie, and Taylor for <span class="hlt">large</span>-aspect-ratio <span class="hlt">circular</span> tokamaks is analyzed in the limit of <span class="hlt">large</span> pressure gradient, and corresponding expressions for stability boundaries are derived. In particular, it is found that for a fixed radial wave number, there exists an infinite sequence of unstable bands, and that minimizing over the radial wave numbers leads to asymptotic merging between the neighboring bands.</p> <div class="credits"> <p class="dwt_author">Chen, L.; Bondeson, A.; Chance, M.S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20130012045&hterms=Carson&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DC%2BCarson"> <span id="translatedtitle">Polarimetric Imaging of <span class="hlt">Large</span> Cavity Structures in the Pre-transitional Protoplanetary Disk Around PDS 70: <span class="hlt">Observations</span> of the Disk</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We present high-resolution H-band polarized intensity (FWHM=0".1:14AU) and L'-band imaging data(FWHM= 0".11:15 AU) of the circumstellar disk around the weak-lined T Tauri star PDS 70 in Centaurus at a radial distance of 28 AU (0".2) up to 210 AU (1".5). In both images, a giant inner gap is clearly resolved for the first time, and the radius of the gap is approx.70 AU. Our data show that the geometric center of the disk shifts by approx.6 AU toward the minor axis. We confirm that the brown dwarf companion candidate to the north of PDS 70 is a background star based on its proper motion. As a result of spectral energy distribution fitting by Monte Carlo radiative transfer modeling, we infer the existence of an optically thick inner disk at a few AU. Combining our <span class="hlt">observations</span> and modeling, we classify the disk of PDS 70 as a pre-transitional disk. Furthermore, based on the analysis of L'-band imaging data, we put an upper limit of approx.30 to approx.50 M(sub J) on the mass of companions within the gap. Taking into account the presence of the <span class="hlt">large</span> and sharp gap, we suggest that the gap could be formed by dynamical interactions of sub-stellar companions or multiple unseen giant planets in the gap. Key words: planetary systems - polarization - protoplanetary disks - stars: individual (PDS 70) - stars: pre-main sequence.</p> <div class="credits"> <p class="dwt_author">Hashimoto, J.; Dong, R.; Kudo, T.; Honda, M.; McClure, M. K.; Zhu, Z.; Muto, T.; Wisniewski, J.; Abe, L.; Brandner, W.; Brandt, T.; Carson, J.; Egner, S.; Feldt, M.; Fukagawa, M.; Goto, M.; Grady, C. A.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K.; Ishii, M.; McElwain, M. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AIPC.1133..362F"> <span id="translatedtitle">Spectral Lags of GRBs <span class="hlt">observed</span> with INTEGRAL and the inferred <span class="hlt">large</span> population of low-luminosity GRBs</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The ?-ray instruments on board INTEGRAL detected and localised 47 GRBs from its launch in October 2002 up to July 2007. The peak flux distribution shows that INTEGRAL detects proportionally more weak GRBs than Swift because of its higher sensitivity in a smaller field of view. The all-sky rate of GRBs above ~0.15 ph cm-2 s-1 is ~1400yr-1 in the fully coded field of view of IBIS. Spectral lags i.e. the time delay in the arrival of low-energy ?-rays with respect to high-energy ?-rays, are measured for 31 of the GRBs. Two groups are identified in the spectral lag distribution of INTEGRAL GRBs, one with short lags <0.75 s (between 25-50 keV and 50-300 keV) and one with long lags >0.75 s. Most of the long-lag GRBs are inferred to have low redshifts because of their long spectral lags, their tendency to have low peak energies, and their faint optical and X-ray afterglows. They are mainly <span class="hlt">observed</span> in the direction of the supergalactic plane with a quadrupole moment of Q = -0.225+/-0.090 and hence reflect the local <span class="hlt">large</span>-scale structure of the Universe. The rate of long-lag GRBs with inferred low luminosity is ~25% of Type Ib/c SNe. Some of these bursts could be produced by the collapse of a massive star without a SN. Alternatively, they could result from a different progenitor, such as the merger of two white dwarfs or a white dwarf with a neutron star or black hole, possibly in the cluster environment without a host galaxy.</p> <div class="credits"> <p class="dwt_author">Foley, S.; McGlynn, S.; Hanlon, L.; McBreen, S.; McBreen, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">370</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18902079"> <span id="translatedtitle">Polarization of Synchrotron Radiation from Relativistic Schwarzschild <span class="hlt">Circular</span> Geodesics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The pattern of geodesic synchrotron radiation emitted by a charge in an orbit close to the <span class="hlt">circular</span> photon orbit at 3M around a nonrotating black hole of mass M is studied. The analysis is carried out using Stokes parameters, which completely characterize the state of the wave. The linear polarization, as <span class="hlt">observed</span> at infinity, is total in the orbital plane</p> <div class="credits"> <p class="dwt_author">R. A. Breuer; C. V. Vishveshwara</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">371</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16615573"> <span id="translatedtitle">Vibration of micromachined <span class="hlt">circular</span> piezoelectric diaphragms.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Electrically and mechanically excited resonances in micromachined <span class="hlt">circular</span> piezoelectric diaphragms have been investigated. The diaphragm structures were piezoelectric unimorphs consisting of Pb(Zr0.52,Ti0.48)O3 (PZT) films and thermally grown silicon oxide (SiO2) layers. For electrical excitation, ring-shaped interdigitated (IDT) electrodes formed on the top of the PZT layer were used to induce strain in the diaphragms. The diaphragm structures behaved much like <span class="hlt">circular</span> membranes in which the membrane tension was approximately 206 N/m, at the fundamental modes. For higher modes, the resonance frequencies deviated from the theoretical values due to the finite stiffness of the diaphragms. Under mechanical drive, both symmetric and asymmetric modes were excited. However, for electrical excitation, the symmetric modes were dominant due to the symmetry of the driving IDT electrodes. At a pressure of 727 Torr, the quality factor was approximately 250, and this rose to 2000 at pressures below 1 Torr. When a forward bias was applied to the diaphragm, the membrane tension decreased, but under reverse biases the tension increased. However, because of repoling under reverse biases greater than the coercive field of the PZT film, the achievable increase in the membrane tension was limited. In the diaphragm structure, the nonlinear vibration was governed by geometric nonlinearity rather than material nonlinearity. In addition, evidence of non-180 degrees domain wall motion of the PZT layer in released diaphragms was <span class="hlt">observed</span>. PMID:16615573</p> <div class="credits"> <p class="dwt_author">Hong, Eunki; Trolier-McKinstry, Susan; Smith, Robert; Krishnaswamy, Silai V; Freidhoff, Carl B</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">372</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3905713"> <span id="translatedtitle">Chiral plasmonic DNA nanostructures with switchable <span class="hlt">circular</span> dichroism</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Circular</span> dichroism spectra of naturally occurring molecules and also of synthetic chiral arrangements of plasmonic particles often exhibit characteristic bisignate shapes. Such spectra consist of peaks next to dips (or vice versa) and result from the superposition of signals originating from many individual chiral objects oriented randomly in solution. Here we show that by first aligning and then toggling the orientation of DNA-origami-scaffolded nanoparticle helices attached to a substrate, we are able to reversibly switch the optical response between two distinct <span class="hlt">circular</span> dichroism spectra corresponding to either perpendicular or parallel helix orientation with respect to the light beam. The <span class="hlt">observed</span> directional <span class="hlt">circular</span> dichroism of our switchable plasmonic material is in good agreement with predictions based on dipole approximation theory. Such dynamic metamaterials introduce functionality into soft matter-based optical devices and may enable novel data storage schemes or signal modulators. PMID:24336125</p> <div class="credits"> <p class="dwt_author">Schreiber, Robert; Luong, Ngoc; Fan, Zhiyuan; Kuzyk, Anton; Nickels, Philipp C.; Zhang, Tao; Smith, David M.; Yurke, Bernard; Kuang, Wan; Govorov, Alexander O.; Liedl, Tim</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">373</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013NatCo...4E2948S"> <span id="translatedtitle">Chiral plasmonic DNA nanostructures with switchable <span class="hlt">circular</span> dichroism</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Circular</span> dichroism spectra of naturally occurring molecules and also of synthetic chiral arrangements of plasmonic particles often exhibit characteristic bisignate shapes. Such spectra consist of peaks next to dips (or vice versa) and result from the superposition of signals originating from many individual chiral objects oriented randomly in solution. Here we show that by first aligning and then toggling the orientation of DNA-origami-scaffolded nanoparticle helices attached to a substrate, we are able to reversibly switch the optical response between two distinct <span class="hlt">circular</span> dichroism spectra corresponding to either perpendicular or parallel helix orientation with respect to the light beam. The <span class="hlt">observed</span> directional <span class="hlt">circular</span> dichroism of our switchable plasmonic material is in good agreement with predictions based on dipole approximation theory. Such dynamic metamaterials introduce functionality into soft matter-based optical devices and may enable novel data storage schemes or signal modulators.</p> <div class="credits"> <p class="dwt_author">Schreiber, Robert; Luong, Ngoc; Fan, Zhiyuan; Kuzyk, Anton; Nickels, Philipp C.; Zhang, Tao; Smith, David M.; Yurke, Bernard; Kuang, Wan; Govorov, Alexander O.; Liedl, Tim</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">374</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ldeo.columbia.edu/~shaw/publications/ShawS01.pdf"> <span id="translatedtitle">GEOPHYSICAL RESEARCH LETTERS, VOL. 0, NO. 0, PAGES 0-0, M 0, 2001 Slip-length scaling in <span class="hlt">large</span> earthquakes: <span class="hlt">Observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">. Scholz Lamont­Doherty Earth Observatory, Columbia University, New York Abstract. For twenty years earthquakes: <span class="hlt">Observations</span> and theory and implications for earthquake physics Bruce E. Shaw and Christopher H there has been a dilemma in earthquake physics, because the <span class="hlt">observed</span> scaling law for <span class="hlt">large</span> earthquakes did</p> <div class="credits"> <p class="dwt_author">Shaw, Bruce E.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">375</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24996997"> <span id="translatedtitle">Engineering strictosidine synthase: Rational design of a small, focused <span class="hlt">circular</span> permutation library of the ?-propeller fold enzyme.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Strictosidine synthases catalyze the formation of strictosidine, a key intermediate in the biosynthesis of a <span class="hlt">large</span> variety of monoterpenoid indole alkaloids. Efforts to utilize these biocatalysts for the preparation of strictosidine analogs have however been of limited success due to the high substrate specificity of these enzymes. We have explored the impact of a protein engineering approach called <span class="hlt">circular</span> permutation on the activity of strictosidine synthase from the Indian medicinal plant Rauvolfia serpentina. To expedite the discovery process, our study departs from the usual process of creating a random protein library, followed by extensive screening. Instead, a small, focused library of <span class="hlt">circular</span> permutated variants of the six bladed ?-propeller protein was prepared, specifically probing two regions which cover the enzyme active site. The <span class="hlt">observed</span> activity changes suggest important roles of both regions in protein folding, stability and catalysis. PMID:24996997</p> <div class="credits"> <p class="dwt_author">Fischereder, Eva; Pressnitz, Desiree; Kroutil, Wolfgang; Lutz, Stefan</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-15</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">376</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22004306"> <span id="translatedtitle"><span class="hlt">OBSERVATIONS</span> OF THE NEAR- TO MID-INFRARED UNIDENTIFIED EMISSION BANDS IN THE INTERSTELLAR MEDIUM OF THE <span class="hlt">LARGE</span> MAGELLANIC CLOUD</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present the results of near- to mid-infrared slit spectroscopic <span class="hlt">observations</span> (2.55-13.4 {mu}m) of the diffuse emission toward nine positions in the <span class="hlt">Large</span> Magellanic Cloud with the infrared camera on board AKARI. The target positions are selected to cover a wide range of the intensity of the incident radiation field. The unidentified infrared bands at 3.3, 6.2, 7.7, 8.6, and 11.3 {mu}m are detected toward all the targets and ionized gas signatures; hydrogen recombination lines and ionic forbidden lines are detected toward three of them. We classify the targets into two groups: those without the ionized gas signatures (Group A) and those with the ionized signatures (Group B). Group A includes molecular clouds and photodissociation regions, whereas Group B consists of H II regions. In Group A, the band ratios of I{sub 3.3{mu}m}/I{sub 11.3{mu}m}, I{sub 6.2{mu}m}/I{sub 11.3{mu}m}, I{sub 7.7{mu}m}/I{sub 11.3{mu}m}, and I{sub 8.6{mu}m}/I{sub 11.3{mu}m} show positive correlation with the IRAS and AKARI colors, but those of Group B do not follow the correlation. We discuss the results in terms of the polycyclic aromatic hydrocarbon (PAH) model and attribute the difference to the destruction of small PAHs and an increase in the recombination due to the high electron density in Group B. In the present study, the 3.3 {mu}m band provides crucial information on the size distribution and/or the excitation conditions of PAHs and plays a key role in the distinction of Group A from B. The results suggest the possibility of the diagram of I{sub 3.3{mu}m}/I{sub 11.3{mu}m} versus I{sub 7.7{mu}m}/I{sub 11.3{mu}m} as an efficient diagnostic tool to infer the physical conditions of the interstellar medium.</p> <div class="credits"> <p class="dwt_author">Mori, Tamami I.; Sakon, Itsuki; Onaka, Takashi; Ohsawa, Ryou [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kaneda, Hidehiro [Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602 (Japan); Umehata, Hideki, E-mail: morii@astron.s.u-tokyo.ac.jp, E-mail: isakon@astron.s.u-tokyo.ac.jp, E-mail: onaka@astron.s.u-tokyo.ac.jp [Institute of Astronomy, Graduate School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">377</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvA..90d3417P"> <span id="translatedtitle"><span class="hlt">Circular</span> dichroism in molecular-frame photoelectron angular distributions in the dissociative photoionization of H2 and D2 molecules</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The presence of net <span class="hlt">circular</span> dichroism in the photoionization of nonchiral homonuclear molecules has been put in evidence recently through the measurement of molecular-frame photoelectron angular distributions in dissociative photoionization of H2 [Dowek et al., Phys. Rev. Lett. 104, 233003 (2010), 10.1103/PhysRevLett.104.233003]. In this work we present a detailed study of <span class="hlt">circular</span> dichroism in the photoelectron angular distributions of H2 and D2 molecules, oriented perpendicularly to the propagation vector of the <span class="hlt">circularly</span> polarized light, at different photon energies (20, 27, and 32.5 eV). <span class="hlt">Circular</span> dichroism in the angular distributions at 20 and to a <span class="hlt">large</span> extent 27 eV exhibits the usual pattern in which inversion symmetry is preserved. In contrast, at 32.5 eV, the inversion symmetry breaks down, which eventually leads to total <span class="hlt">circular</span> dichroism after integration over the polar emission angle. Time-dependent ab initio calculations support and explain the <span class="hlt">observed</span> results for H2 in terms of quantum interferences between direct photoionization and delayed autoionization from the Q1 and Q2 doubly excited states into ionic states (1 s ?g and 2 p ?u ) of different inversion symmetry. Nevertheless, for D2 at 32.5 eV, there is a particular case where theory and experiment disagree in the magnitude of the symmetry breaking: when D+ ions are produced with an energy of around 5 eV. This reflects the subleties associated to such simple molecules when exposed to this fine scrutiny.</p> <div class="credits"> <p class="dwt_author">Pérez-Torres, J. F.; Sanz-Vicario, J. L.; Veyrinas, K.; Billaud, P.; Picard, Y. J.; Elkharrat, C.; Poullain, S. Marggi; Saquet, N.; Lebech, M.; Houver, J. C.; Martín, F.; Dowek, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">378</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18396231"> <span id="translatedtitle">Experimental <span class="hlt">observation</span> of isolated <span class="hlt">large</span> transverse energy electrons with associated missing energy at sqrt(s)=540 GeV</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We report the results of two searches made on data recorded at the CERN SPS Proton-Antiproton Collider: one for isolated <span class="hlt">large</span>-ET electrons, the other for <span class="hlt">large</span>-ET neutrinos using the technique of missing transverse energy. Both searches converge to the same events, which have the signature of a two-body decay of a particle of mass ~80 GeV\\/c2. The topology as well</p> <div class="credits"> <p class="dwt_author">Geoffrey T J Arnison; Alan Astbury; Bernard Aubert; Cesare Bacci; G. Bauer; A. Bézaguet; R. Böck; T. J. V. Bowcock; M. Calvetti; T. Carroll; P. Catz; P. Cennini; S. Centro; F. Ceradini; S. Cittolin; D. Cline; C. Cochet; J. Colas; M. Corden; D. Dallman; M. Debeer; M. della Negra; M. Demoulin; D. Denegri; A. di Ciaccio; D. Dibitonto; L. Dobrzynski; J. D. Dowell; M. Edwards; K. Eggert; E. Eisenhandler; N. Ellis; P. Erhard; H. Faissner; G. Fontaine; R. Frey; R. Frühwirth; J. Garvey; S. Geer; C. Ghesquière; P. Ghez; K. L. Giboni; W. R. Gibson; Y. Giraud-Héraud; A. Givernaud; A. Gonidec; G. Grayer; P. Gutierrez; T. Hansl-Kozanecka; W. J. Haynes; L. O. Hertzberger; C. Hodges; D. Hoffmann; H. Hoffmann; D. J. Holthuizen; R. J. Homer; A. Honma; W. Jank; G. Jorat; P. I. P. Kalmus; V. Karimäki; R. Keeler; I. Kenyon; A. Kernan; R. Kinnunen; H. Kowalski; W. Kozanecki; D. Kryn; F. Lacava; J.-P. Laugier; J P Laugier; H. Lehmann; K. Leuchs; A. Lévêque; E. Linglin; E. Locci; M. Loret; J.-J. Malosse; T. Markiewicz; G. Maurin; T. McMahon; J.-P. Mendiburu; M.-N. Minard; M. Moricca; H. Muirhead; F. Muller; A. K. Nandi; L. Naumann; A. Norton; A. Orkin-Lecourtois; L. Paoluzi; G. Petrucci; G. Piano Mortari; M. Pimiä; A. Placci; E. Radermacher; J. Ransdell; H. Reithler; J.-P. Revol; J. Rich; M. Rijssenbeek; C. Roberts; J. Rohlf; P. Rossi; Carlo Rubbia; Bernard Sadoulet; G. Sajot; G. Salvi; J. Salvini; Jean Sass; A. Saudraix; Aurore Savoy-Navarro; D. Schinzel; W. Scott; T. P. Shah; Michel Spiro; J. Strauss; K. Sumorok; F. Szoncso; D. Smith; Charling Tao; G. Thompson; J. Timmer; E. Tscheslog; Jorma Tuominiemi; S. van der Meer; J.-P. Vialle; J. Vrana; V. Vuillemin; H. D. Wahl; P M Watkins; J. Wilson; Y. G. Xie; Michel Jean Paul Yvert; Erwin Zurfluh</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">379</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/901264"> <span id="translatedtitle">Chandra And HST <span class="hlt">Observations</span> of Gamma-Ray Blazars: Comparing Jet Emission at Small And <span class="hlt">Large</span> Scales</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We present new Chandra and HST data for four gamma-ray blazars selected on the basis of radio morphology with the aim of revealing X-ray and optical emission from their jets at <span class="hlt">large</span> scales. All the sources have been detected. Spectral Energy Distributions of the <span class="hlt">large</span> scale jets are obtained as well as new X-ray spectra for the blazar cores. Modeling for each object the core (sub-pc scale) and <span class="hlt">large</span>-scale ({approx}> 100 kpc) jet SEDs, we derive the properties of the same jet at the two scales. The comparison of speeds and powers at different scales supports a simple scenario for the dynamics and propagation of high power relativistic jets.</p> <div class="credits"> <p class="dwt_author">Tavecchio, Fabrizio; Maraschi, L.; Wolter, A.; /Brera Observ.; Cheung, C.C.; /KIPAC, Menlo Park; Sambruna, R.M.; /NASA, Goddard; Urry, C.M.; /Yale U., Dept. Astron.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-03-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">380</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JGRA..119.6846G"> <span id="translatedtitle">Constructive interference of <span class="hlt">large</span>-scale gravity waves excited by interplanetary shock on 29 October 2003: CHAMP <span class="hlt">observation</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper we report the detection of full constructive interference between two <span class="hlt">large</span>-scale gravity waves in the upper thermosphere from the CHAMP accelerometer measurements. The two waves are separately excited in northern and southern auroral regions by the shock-induced auroral intensification on 29 October 2003. They propagate equatorward and encounter near the equator, where constructive interference occurs and causes nightside equatorial neutral density enhancements of ˜60%. This result demonstrates that the constructive interference can be a potential mechanism for <span class="hlt">large</span> density increases in the equatorial region during magnetically active periods.</p> <div class="credits"> <p class="dwt_author">Guo, Jianpeng; Liu, Huixin; Feng, Xueshang; Wan, Weixing; Deng, Yue; Liu, Chaoxu</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_18");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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<a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a style="font-weight: bold;">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_21");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">381</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930081360&hterms=stress+effects+body&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstress%2Beffects%2Bbody"> <span id="translatedtitle"><span class="hlt">Circular</span> motion of bodies of revolution</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The <span class="hlt">circular</span> motion for airship-like bodies has thus far been calculated only for a prolate ellipsoid of revolution (reference 1, p.133 and reference 2). In this paper, however, the <span class="hlt">circular</span> motion of elongated bodies of revolution more nearly resembling airships will be investigated. The results will give the effect of rotation on the pressure distribution and thus yield some information as to the stresses set up in an airship in <span class="hlt">circular</span> flight.</p> <div class="credits"> <p class="dwt_author">Kaplan, Carl</p> <p class="dwt_publisher"></p> <p class="publishDate">1936-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">382</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://arxiv.org/pdf/math-ph/0412050v1"> <span id="translatedtitle">Narrow Escape, Part II: The <span class="hlt">circular</span> disk</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/epsearch/">E-print Network</a></p> <p class="result-summary">We consider Brownian motion in a <span class="hlt">circular</span> disk $\\Omega$, whose boundary $\\p\\Omega$ is reflecting, except for a small arc, $\\p\\Omega_a$, which is absorbing. As $\\epsilon=|\\partial \\Omega_a|/|\\partial \\Omega|$ decreases to zero the mean time to absorption in $\\p\\Omega_a$, denoted $E\\tau$, becomes infinite. The narrow escape problem is to find an asymptotic expansion of $E\\tau$ for $\\epsilon\\ll1$. We find the first two terms in the expansion and an estimate of the error. The results are extended in a straightforward manner to planar domains and two-dimensional Riemannian manifolds that can be mapped conformally onto the disk. Our results improve the previously derived expansion for a general smooth domain, $E\\tau = \\ds{\\frac{|\\Omega|}{D\\pi}}[\\log\\ds{\\frac{1}{\\epsilon}}+O(1)],$ ($D$ is the diffusion coefficient) in the case of a <span class="hlt">circular</span> disk. We find that the mean first passage time from the center of the disk is $E[\\tau | \\x(0)=\\mb{0}]=\\ds{\\frac{R^2}{D}}[\\log\\ds{\\frac{1}{\\epsilon}} + \\log 2 +\\ds{{1/4}} + O(\\epsilon)]$. The second term in the expansion is needed in real life applications, such as trafficking of receptors on neuronal spines, because $\\log\\ds{\\frac{1}{\\epsilon}}$ is not necessarily <span class="hlt">large</span>, even when $\\epsilon$ is small. We also find the singular behavior of the probability flux profile into $\\p\\Omega_a$ at the endpoints of $\\p\\Omega_a$, and find the value of the flux near the center of the window.</p> <div class="credits"> <p class="dwt_author">A. Singer; Z. Schuss; D. Holcman</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">383</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22034307"> <span id="translatedtitle">Branching and <span class="hlt">circular</span> features in high dimensional data.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Large</span> <span class="hlt">observations</span> and simulations in scientific research give rise to high-dimensional data sets that present many challenges and opportunities in data analysis and visualization. Researchers in application domains such as engineering, computational biology, climate study, imaging and motion capture are faced with the problem of how to discover compact representations of high-dimensional data while preserving their intrinsic structure. In many applications, the original data is projected onto low-dimensional space via dimensionality reduction techniques prior to modeling. One problem with this approach is that the projection step in the process can fail to preserve structure in the data that is only apparent in high dimensions. Conversely, such techniques may create structural illusions in the projection, implying structure not present in the original high-dimensional data. Our solution is to utilize topological techniques to recover important structures in high-dimensional data that contains non-trivial topology. Specifically, we are interested in high-dimensional branching structures. We construct local circle-valued coordinate functions to represent such features. Subsequently, we perform dimensionality reduction on the data while ensuring such structures are visually preserved. Additionally, we study the effects of global <span class="hlt">circular</span> structures on visualizations. Our results reveal never-before-seen structures on real-world data sets from a variety of applications. PMID:22034307</p> <div class="credits"> <p class="dwt_author">Wang, Bei; Summa, Brian; Pascucci, Valerio; Vejdemo-Johansson, Mikael</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">384</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011PhRvE..83f6204H"> <span id="translatedtitle">Parameter-dependent spectral statistics of chaotic quantum graphs: Neumann versus <span class="hlt">circular</span> orthogonal ensemble boundary conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The parameter-dependent spectral statistics of totally connected quantum graphs with n=4-30 vertices, such as the parametric velocities correlation functions and the distribution of curvatures, are studied. The inverse participation ratio (IPR), an important measure of localization effects, was also numerically investigated. In the calculations, we successfully used two different theoretical approaches. The first approach was based on the graphs’ eigenenergies and wave functions calculations, while the second one used the eigenphases and the eigenvectors of the bond scattering matrix S(k). We considered graphs with Neumann and <span class="hlt">circular</span> orthogonal ensemble (COE) boundary conditions. We show that in contrast to <span class="hlt">large</span> Neumann graphs, for which the departure of many parameter-dependent spectral statistics from the random matrix theory (RMT) predictions is <span class="hlt">observed</span>, for <span class="hlt">large</span> COE graphs, the spectral statistics and IPR are in good agreement with the RMT predictions.</p> <div class="credits"> <p class="dwt_author">Hul, Oleh; Sirko, Leszek</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">385</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.physicsclassroom.com/Class/circles/U6L1a.cfm"> <span id="translatedtitle">Physics Classroom: Motion Characteristics for <span class="hlt">Circular</span> Motion</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This resource guides the user through characteristics of <span class="hlt">circular</span> motion. The same concepts and principles used to describe the motion of an object can also be used to describe and explain the motion of objects in <span class="hlt">circular</span> pathways. This tutorial is broken into five sections addressing: the mechanics of <span class="hlt">circular</span> motion, centripetal force, algebraic and trigonometric problems and solutions, and a full chapter that debunks the centrifugal "force" misconception. The interactive problems use diagrams and force vectors to help students visualize how vector components affect the way <span class="hlt">circular</span> motion is characterized.</p> <div class="credits"> <p class="dwt_author">Henderson, Tom</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-18</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">386</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007PhDT.......191B"> <span id="translatedtitle">Controlled and uncontrolled motion in the <span class="hlt">circular</span>, restricted three-body problem: Dynamically natural spacecraft formations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Spacecraft formation flying involves operating multiple spacecraft in a pre-determined geometrical shape such that the configuration yields both individual and system benefits. One example is an over-flight of the same spatial position by spacecraft in geocentric orbit with the intent to create a complementary data set of remotely sensed <span class="hlt">observables</span>. Another example is controlling to a high degree of accuracy the distance between spacecraft in heliocentric orbit to create a virtual, <span class="hlt">large</span>-diameter interferometer telescope. Although Keplerian orbits provide the basic framework for general and precision spacecraft formation flying they also present limitations. Spacecraft are generally constrained to operate only in <span class="hlt">circular</span> and elliptical orbits, parabolic paths, or hyperbolic trajectories around celestial bodies. Applying continuation methods and bifurcation theory techniques to the <span class="hlt">circular</span>, restricted three-body problem - where stable and unstable periodic orbits exist around equilibrium points - creates an environment that is more orbit rich. After surmounting a similar challenge with test particles in the <span class="hlt">circular</span>, restricted three-vortex problem in fluid mechanics as a proof-of-concept, it was shown that spacecraft traveling in uncontrolled motion along separate and distinct planar or three-dimensional periodic orbits could be placed in controlled motion, i.e. a controller is enabled and later disabled at precisely the proper positions, to have them phase-locked on a single periodic orbit. Although it was possible to use this controller in a resonant frequency/orbit approach to establish a formation, it was clearly shown that a separate controller could be used in conjunction with the first to expedite the formation establishment process. Creation of these dynamically natural spacecraft formations or multi-spacecraft platforms will enable the 'loiter, synchronize/coordinate, and <span class="hlt">observe</span>' approach for future engineering and scientific missions where flexibility is a top-level requirement and key to mission success.</p> <div class="credits"> <p class="dwt_author">Basilio, Ralph Ramos</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">387</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996GeoRL..23.2125B"> <span id="translatedtitle">A <span class="hlt">large</span> 13CO deficit in the lower Antarctic stratosphere due to “Ozone Hole” Chemistry: Part I, <span class="hlt">Observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Isotope and concentration measurements are reported for CO and CH4 in air collected in the upper troposphere and lower stratosphere between New Zealand and Antarctica in October 1993. The 13C/12C ratio of CO for the stratospheric samples, which are identified using calculated potential vorticity and coherent isotope data, like the abundance of 14CO molecules, are much lower than all previously reported atmospheric values. The measurements manifest a very steep decrease in ?13C with declining CO, with one sample reaching a ?13C value relative to V-PDB of -43‰ at 20 ppbv CO. This <span class="hlt">large</span> isotope shift is caused by the local production of several ppbv of extremely depleted CO. Not only is C4 itself a 13C depleted precursor of CO, it is specifically the recently discovered <span class="hlt">large</span> fractionation in Cl+CH4, and the availability of free Cl during ozone hole conditions, which causes the effect.</p> <div class="credits"> <p class="dwt_author">Brenninkmeijer, Carl A. M.; Müller, Rolf; Crutzen, Paul J.; Lowe, Dave C.; Manning, Martin R.; Sparks, Rodger J.; van Velthoven, Peter F. J.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">388</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/44469724"> <span id="translatedtitle"><span class="hlt">Observed</span> Relationships between <span class="hlt">Large</span>-Scale Tropical Convection and the Tropical Circulation on Subseasonal Time Scales during Northern Hemisphere Winter</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The work presented is a correlative study of the interaction between <span class="hlt">large</span>-scale tropical convection and midlatitude wind anomalies, and the tropical wind field on subseasonal time scales. Outgoing longwave radiation (OLR) is used as a proxy for convection. Correlations are calculated from six years of 5-day averaged data for the December-February (DJF) season. The seasonal cycle and interannual variability are</p> <div class="credits"> <p class="dwt_author">Brant Liebmann</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">389</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUFMSM12B..08P"> <span id="translatedtitle">Cluster <span class="hlt">Observations</span> of Reconnection at the Magnetopause and in the Cusp: Implications for the <span class="hlt">Large</span>-Scale Nature of Reconnection</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We survey the occurrence of reconnection at the magnetopause and in the cusp using measurements from the CIS and FGM experiments. We present evidence for reconnection occurring both equatorward and poleward of the cusp for different IMF orientations. The multi-spacecraft measurements reveal that under steady IMF conditions, reconnection is <span class="hlt">large</span> scale and occurs continuously over an extended period of time, but the reconnection rate may be modulated.</p> <div class="credits"> <p class="dwt_author">Phan, T.; Carlson, C.; Reme, H.; Dunlop, M.; Balogh, A.; Paschmann, G.; Klecker, B.; Bosqued, J. M.; Dandouras, I.; Lavraud, B.; Sauvaud, J. A.; Kistler, L.; Moebius, E.; Twitty, C.; McFadden, J.; Parks, G.; Bavassano-Cattaneo, M. B.; Korth, A.; Lundin, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">390</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56775243"> <span id="translatedtitle"><span class="hlt">Observation</span> of an anomalously <span class="hlt">large</span> blueshift of the photoluminescence peak and evidence of band-gap renormalization in InP\\/InAs\\/InP quantum wires</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have investigated polarization-dependent photoluminescence in InP\\/InAs\\/InP quantum wires directly formed on the top of InP substrates. With excitation laser intensity we have <span class="hlt">observed</span> an anomalously <span class="hlt">large</span> blueshift of the photoluminescence peak using a cw laser with extremely low intensities. We have also <span class="hlt">observed</span> evidence of band-gap renormalization. In addition, we have measured two-photon luminescence spectra and confirmed their dependence</p> <div class="credits"> <p class="dwt_author">Xiaodong Mu; Ioulia B. Zotova; Yujie J. Ding; Haeyeon Yang; Gregory J. Salamo</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">391</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009ntfm.book...73S"> <span id="translatedtitle">Numerical Studies of Flow Past Two Side-by-Side <span class="hlt">Circular</span> Cylinders</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Multiple <span class="hlt">circular</span> cylindrical configurations are widely used in engineering applications. The fluid dynamics of the flow around two identical <span class="hlt">circular</span> cylinders in side-by-side arrangement has been investigated by both experiments and numerical simulations. The center-to-center transverse pitch ratio T/D plays an important role in determining the flow features. It is <span class="hlt">observed</span> that for 1 < T/D < 1.1 to 1.2, a single vortex street is formed; for 1.2< T/D < 2 to 2.2, bi-stable narrow and wide wakes are formed; for 2.7< T/D < 4 or 5, anti-phase or in-phase vortex streets are formed. In the current study, the vortex structures of turbulent flows past two slightly heated side-by-side <span class="hlt">circular</span> cylinders are investigated employing the <span class="hlt">large</span> eddy simulation (LES). Simulations are performed using a commercial CFD software, FLUENT. The Smagorinsky-Lilly subgrid-scale model is employed for the <span class="hlt">large</span> eddy simulation. The Reynolds number based on free-stream velocity and cylinder diameter is 5 800, which is in the subcritical regime. The transverse pitch ratio T/D = 3 is investigated. Laminar boundary layer, transition in shear layer, flow separation, <span class="hlt">large</span> vortex structures and flow interference in the wake are all involved in the flow. Such complex flow features make the current study a challenging task. Both flow field and temperature field are investigated. The calculated results are analyzed and compared with experimental data. The simulation results are qualitatively in accordance with experimental <span class="hlt">observations</span>. Two anti-phase vortex streets are obtained by the <span class="hlt">large</span>-eddy simulation, which agrees with the experimental <span class="hlt">observation</span>. At this transverse pitch ratio, these two cylinders behave as independent, isolated single cylinder in cross flow. The time-averaged streamwise velocity and temperature at x/D=10 are in good agreement with the experimental data. Figure1 displays the instantaneous spanwise vorticity at the center plane.</p> <div class="credits"> <p class="dwt_author">Shao, J.; Zhang, C.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">392</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17301020"> <span id="translatedtitle"><span class="hlt">Observations</span> of wild hunting behaviour and bioluminescence of a <span class="hlt">large</span> deep-sea, eight-armed squid, Taningia danae.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Our newly developed underwater high definition video camera system took the first live images of adults of the mesopelagic <span class="hlt">large</span> squid, Taningia danae, between 240 and 940 m deep off Ogasawara Islands, western North Pacific. The resulting footage includes attacking and bioluminescence behaviours, and reveals that T. danae is far from the sluggish neutrally buoyant deep-sea squid previously suspected. It can actively swim both forward and backward freely by flapping its <span class="hlt">large</span> muscular triangular fins and changes direction quickly through bending its flexible body. It can attain speeds of 2-2.5 ms(-1) (7.2-9 km h(-1)) when attacking bait rigs. They emitted short bright light flashes from their <span class="hlt">large</span> arm-tip photophores before final assault, which might act as a blinding flash for prey as well as a means of measuring target distance in a dark deep-sea environment. They also emitted long and short glows separated by intervals while wandering around the double torch lights attached to the bait rig, suggestive of potential courtship behaviours during mating. PMID:17301020</p> <div class="credits"> <p class="dwt_author">Kubodera, Tsunemi; Koyama, Yasuhiro; Mori, Kyoichi</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-04-22</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">393</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3832744"> <span id="translatedtitle">A <span class="hlt">large</span> hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric <span class="hlt">observations</span> and its implications to the volcanic activity</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a <span class="hlt">large</span> high resistivity anomaly (?100 ?·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (?10 ?·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a <span class="hlt">large</span> hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a <span class="hlt">large</span> hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions. PMID:24126286</p> <div class="credits"> <p class="dwt_author">ALANIS, Paul K. B.; YAMAYA, Yusuke; TAKEUCHI, Akihiro; SASAI, Yoichi; OKADA, Yoshihiro; NAGAO, Toshiyasu</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">394</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24126286"> <span id="translatedtitle">A <span class="hlt">large</span> hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric <span class="hlt">observations</span> and its implications to the volcanic activity.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a <span class="hlt">large</span> high resistivity anomaly (?100 ?·m) with a volume of at least 3 km×3 km×3 km, which is capped by a conductive layer (?10 ?·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a <span class="hlt">large</span> hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a <span class="hlt">large</span> hydrothermal reservoir and the stagnant magma below may have influences on the volcano's activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions. PMID:24126286</p> <div class="credits"> <p class="dwt_author">Alanis, Paul K B; Yamaya, Yusuke; Takeuchi, Akihiro; Sasai, Yoichi; Okada, Yoshihiro; Nagao, Toshiyasu</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">395</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19990031964&hterms=Yamamoto&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DYamamoto%2BT"> <span id="translatedtitle"><span class="hlt">Large</span>-Scale Dynamics of the Magnetospheric Boundary: Comparisons between Global MHD Simulation Results and ISTP <span class="hlt">Observations</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Understanding the <span class="hlt">large</span>-scale dynamics of the magnetospheric boundary is an important step towards achieving the ISTP mission's broad objective of assessing the global transport of plasma and energy through the geospace environment. Our approach is based on three-dimensional global magnetohydrodynamic (MHD) simulations of the solar wind-magnetosphere- ionosphere system, and consists of using interplanetary magnetic field (IMF) and plasma parameters measured by solar wind monitors upstream of the bow shock as input to the simulations for predicting the <span class="hlt">large</span>-scale dynamics of the magnetospheric boundary. The validity of these predictions is tested by comparing local data streams with time series measured by downstream spacecraft crossing the magnetospheric boundary. In this paper, we review results from several case studies which confirm that our MHD model reproduces very well the <span class="hlt">large</span>-scale motion of the magnetospheric boundary. The first case illustrates the complexity of the magnetic field topology that can occur at the dayside magnetospheric boundary for periods of northward IMF with strong Bx and By components. The second comparison reviewed combines dynamic and topological aspects in an investigation of the evolution of the distant tail at 200 R(sub E) from the Earth.</p> <div class="credits"> <p class="dwt_author">Berchem, J.; Raeder, J.; Ashour-Abdalla, M.; Frank, L. A.; Paterson, W. R.; Ackerson, K. L.; Kokubun, S.; Yamamoto, T.; Lepping, R. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">396</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JPCM...26G5501H"> <span id="translatedtitle">Angle-resolved photoemission spectroscopy study on graphene using <span class="hlt">circularly</span> polarized light</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have investigated graphene using <span class="hlt">circularly</span> polarized light via angle-resolved photoemission spectroscopy. We <span class="hlt">observe</span> that photoelectron intensity rotates around a constant energy contour towards the opposite direction upon changing the chirality of light. Interestingly, the <span class="hlt">circular</span> dichroism is found to be asymmetric with respect to the Dirac energy, which is not explained by the Berry phase effect (Liu et al 2011 Phys. Rev. Lett. 107 166803). We also report that the energy spectra taken using the light with different chiralities show a finite separation from each other. We discuss possible origins of the unusual <span class="hlt">circular</span> dichroism <span class="hlt">observed</span> in graphene.</p> <div class="credits"> <p class="dwt_author">Hwang, Choongyu</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">397</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/25056276"> <span id="translatedtitle">Angle-resolved photoemission spectroscopy study on graphene using <span class="hlt">circularly</span> polarized light.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We