Behavior of the Martian dayside electron density peak during global dust storms

Abstract. To obtain a comprehensive view on high latitude processes by applying different observation techniques, the SIRCUS campaign was initiated in 2001/2002. This paper compares electron density profiles derived from CHAMP radio occultation data and those measured with the EISCAT facility. Since ionospheric profiling with the help of space-based received GPS is a relatively new technique, validations with established independent instruments are of crucial need. We present 28 profiling events for quasi-statistical analyses, which occurred during the SIRCUS campaigns and describe some of them in more detail. We found out that the majority of profile comparisons in electron density peak value and height, as well as in TEC, lie within the error ranges of the two methods. Differences in the ionospheric quantities do not necessarily occur when the locations of the occultation and of the radar site show considerable distances. Differences are more pronounced when the ionosphere is remarkably structured.

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Ab initio structure solution of proteins at atomic resolution using charge-flipping techniques and cloud computing

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798320015090 ◽

2021 ◽

Vol 77 (1) ◽

pp. 98-107

Author(s):

Alan A. Coelho

Keyword(s):

Cloud Computing ◽

Electron Density ◽

Virtual Machines ◽

Protein Structures ◽

Uranium Atom ◽

Atomic Resolution ◽

Group Symmetry ◽

Density Peak ◽

Computing Platform ◽

Amazon Web Services

Large protein structures at atomic resolution can be solved in minutes using charge-flipping techniques operating on hundreds of virtual machines (computers) on the Amazon Web Services cloud-computing platform driven by the computer programs TOPAS or TOPAS-Academic at a small financial cost. The speed of operation has allowed charge-flipping techniques to be investigated and modified, leading to two strategies that can solve a large range of difficult protein structures at atomic resolution. Techniques include the use of space-group symmetry restraints on the electron density as well as increasing the intensity of a randomly chosen high-intensity electron-density peak. It is also shown that the use of symmetry restraints increases the chance of finding a solution for low-resolution data. Finally, a flipping strategy that negates `uranium atom solutions' has been developed for structures that exhibit such solutions during charge flipping.

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Experimental and database-transferred electron-density analysis and evaluation of electrostatic forces in coumarin-102 dye

Acta Crystallographica Section B Structural Science ◽

10.1107/s0108768112042826 ◽

2012 ◽

Vol 68 (6) ◽

pp. 646-660 ◽

Cited By ~ 6

Author(s):

Yvon Bibila Mayaya Bisseyou ◽

Nouhza Bouhmaida ◽

Benoit Guillot ◽

Claude Lecomte ◽

Noel Lugan ◽

...

Keyword(s):

Charge Density ◽

Electron Density ◽

Dipole Moments ◽

Crystal Form ◽

Density Peak ◽

Charge Delocalization ◽

Molecular Dipole ◽

Atom Model ◽

Topological Features ◽

Coumarin 102

The electron-density distribution of a new crystal form of coumarin-102, a laser dye, has been investigated using the Hansen–Coppens multipolar atom model. The charge density was refined versus high-resolution X-ray diffraction data collected at 100 K and was also constructed by transferring the charge density from the Experimental Library of Multipolar Atom Model (ELMAM2). The topology of the refined charge density has been analysed within the Bader `Atoms In Molecules' theory framework. Deformation electron-density peak heights and topological features indicate that the chromen-2-one ring system has a delocalized π-electron cloud in resonance with the N (amino) atom. The molecular electrostatic potential was estimated from both experimental and transferred multipolar models; it reveals an asymmetric character of the charge distribution across the molecule. This polarization effect is due to a substantial charge delocalization within the molecule. The molecular dipole moments derived from the experimental and transferred multipolar models are also compared with the liquid and gas-phase dipole moments. The substantial molecular dipole moment enhancements observed in the crystal environment originate from the crystal field and from intermolecular charge transfer induced and controlled by C—H...O and C—H...N intermolecular hydrogen bonds. The atomic forces were integrated over the atomic basins and compared for the two electron-density models.

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Перенос тепла и частиц в начальной фазе омических разрядов сферического токамака Глобус-М

Письма в журнал технической физики ◽

10.21883/pjtf.2019.13.47951.17817 ◽

2019 ◽

Vol 45 (13) ◽

pp. 17

Author(s):

А.Ю. Тельнова ◽

Г.С. Курскиев ◽

Н.Н. Бахарев ◽

В.К. Гусев ◽

Е.О. Киселев ◽

...

Keyword(s):

Electron Temperature ◽

Safety Factor ◽

Initial Conditions ◽

Transport Processes ◽

Density Peak ◽

Transport Barriers ◽

Internal Transport Barriers ◽

Plasma Core ◽

Internal Transport ◽

Electron Density Peak

AbstractThe results of experiments and simulations of the transport of heat and particles in the Globus-M spherical tokamak are presented. Investigations were carried out in the ohmic mode in hydrogen and deuterium plasma. It is shown that in the phase of current growth under the same initial conditions, as long as the condition is met at which the minimum of the safety factor exceeds unity, two scenarios of discharge development are possible: with an electron temperature dive or with an electron density peak. After the safety factor reaches the value of 1, the differences are no longer observed. Modeling of transport processes using the ASTRA code showed that the dive of the electron temperature and density is a consequence of the decrease in the transport of heat and particles in the plasma core (i.e., the presence of internal transport barriers).

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Electron density and plasma waves in mid-latitude sporadic-<i>E</i> layer observed during the SEEK-2 campaign

Annales Geophysicae ◽

10.5194/angeo-23-2335-2005 ◽

2005 ◽

Vol 23 (7) ◽

pp. 2335-2345 ◽

Cited By ~ 8

Author(s):

M. Wakabayashi ◽

T. Ono ◽

H. Mori ◽

P. A. Bernhardt

Keyword(s):

Electron Density ◽

Layer Structure ◽

Density Measurement ◽

Plasma Waves ◽

Dual Band ◽

Electron Content ◽

Density Peak ◽

Total Electron ◽

Density Peaks ◽

Impedance Probe

Abstract. The SEEK-2 campaign was carried out over Kyushu Island in Japan on 3 August 2002, by using the two sounding rockets of S310-31 and S310-32. This campaign was planned to elucidate generation mechanisms of Quasi-Periodic Echoes (QPEs) associated with mid-latitude sporadic-E (Es) layers. Electron number densities were successfully measured in the Es layers by using the impedance probe on board two rockets. The plasma waves in the VLF and ELF ranges were also observed on board the S310-32 rocket. Results of electron density measurement showed that there were one or two major peaks in the Es layers along the rockets' trajectories near the altitude of about 10km. There were some smaller peaks associated with the main Es layers in the altitude range from 90 to 120 km. These density peaks were distributed in a very large extent during the SEEK-2 campaign. The Es layer structure is also measured by using the Fixed Bias Probe (FBP), which has a high spatial resolution of several meters (the impedance probe has an altitude resolution of about 400 m). The comparison with the total electron content (TEC) measured by the Dual Band Beacon revealed that the Es layer was also modulated in the horizontal direction with the scale size of 30–40 km. It was shown that the QP echoes observed by the ground-based coherent radar come from the major density peak of the Es layer. The plasma wave instrument detected the enhancement of VLF and ELF plasma waves associated with the operation of the TMA release, and also with the passage of the Es layers. Keywords. Ionosphere (Ionospheric irregularities; Midlatitude ionosphere; Plasma temeperature and density)

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White-Light Coronal Structures: Streamers and CMEs

International Astronomical Union Colloquium ◽

10.1017/s0252921100025045 ◽

1994 ◽

Vol 144 ◽

pp. 82

Author(s):

E. Hildner

Keyword(s):

Emission Line ◽

Electron Density ◽

White Light ◽

Coronal Mass Ejections ◽

X Rays ◽

Solar Cycles ◽

Temperature Function ◽

X Ray ◽

Eclipse Observations ◽

Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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Glycogen in guinea pig neutrophils: Ultrastructural study of neutrophils at the intradermal site of BCG injection

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077207 ◽

1983 ◽

Vol 41 ◽

pp. 726-727

Author(s):

Corazon D. Bucana

Keyword(s):

Bone Marrow ◽

Guinea Pig ◽

Electron Density ◽

Peritoneal Cavity ◽

Ultrastructural Study ◽

Guinea Pigs ◽

Random Distribution ◽

Glycogen Content ◽

Polymorphonuclear Neutrophils ◽

Ultrastructural Studies

In the circulating blood of man and guinea pigs, glycogen occurs primarily in polymorphonuclear neutrophils and platelets. The amount of glycogen in neutrophils increases with time after the cells leave the bone marrow, and the distribution of glycogen in neutrophils changes from an apparently random distribution to large clumps when these cells move out of the circulation to the site of inflammation in the peritoneal cavity. The objective of this study was to further investigate changes in glycogen content and distribution in neutrophils. I chose an intradermal site because it allows study of neutrophils at various stages of extravasation.Initially, osmium ferrocyanide and osmium ferricyanide were used to fix glycogen in the neutrophils for ultrastructural studies. My findings confirmed previous reports that showed that glycogen is well preserved by both these fixatives and that osmium ferricyanide protects glycogen from solubilization by uranyl acetate.I found that osmium ferrocyanide similarly protected glycogen. My studies showed, however, that the electron density of mitochondria and other cytoplasmic organelles was lower in samples fixed with osmium ferrocyanide than in samples fixed with osmium ferricyanide.

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Application of ruthenium red/osmium tetroxide to bacteria, plant and animal tissue

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141998 ◽

1986 ◽

Vol 44 ◽

pp. 54-55

Author(s):

R. L. Grayson ◽

N. A. Rechcigl

Keyword(s):

Electron Microscopy ◽

Electron Density ◽

Osmium Tetroxide ◽

Biological Materials ◽

Ruthenium Red ◽

Animal Tissue

Ruthenium red (RR), an inorganic dye was found to be useful in electron microscopy where it can combine with osmium tetroxide (OsO4) to form a complex with attraction toward anionic substances. Although Martinez-Palomo et al. (1969) were one of the first investigators to use RR together with OsO4, our computor search has shown few applications of this combination in the intervening years. The purpose of this paper is to report the results of our investigations utilizing the RR/OsO4 combination to add electron density to various biological materials. The possible mechanisms by which this may come about has been well reviewed by previous investigators (1,3a,3b,4).

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