2,911 research outputs found
The Deflection of the Two Interacting Coronal Mass Ejections of 2010 May 23-24 as Revealed by Combined In situ Measurements and Heliospheric Imaging
In 2010 May 23-24, SDO observed the launch of two successive coronal mass
ejections (CMEs), which were subsequently tracked by the SECCHI suite onboard
STEREO. Using the COR2 coronagraphs and the heliospheric imagers (HIs), the
initial direction of both CMEs is determined to be slightly west of the
Sun-Earth line. We derive the CME kinematics, including the evolution of the
CME expansion until 0.4 AU. We find that, during the interaction, the second
CME decelerates from a speed above 500 km/s to 380 km/s the speed of the
leading edge of the first CME. STEREO observes a complex structure composed of
two different bright tracks in HI2-A but only one bright track in HI2-B. In
situ measurements from Wind show an "isolated" ICME, with the geometry of a
flux rope preceded by a shock. Measurements in the sheath are consistent with
draping around the transient. By combining remote-sensing and in situ
measurements, we determine that this event shows a clear instance of deflection
of two CMEs after their collision, and we estimate the deflection of the first
CME to be about 10 degrees towards the Sun-Earth line. The arrival time,
arrival speed and radius at Earth of the first CME are best predicted from
remote-sensing observations taken before the collision of the CMEs. Due to the
over-expansion of the CME after the collision, there are few, if any, signs of
interaction in in situ measurements. This study illustrates that complex
interactions during the Sun-to-Earth propagation may not be revealed by in situ
measurements alone.Comment: 14 pages, 8 figures, 1 table, accepted to the Astrophysical Journa
PACE and EISCAT radar observations of short-lived flow bursts on the nightside
Concurrent observations from two widely spaced radar experiments of quasi periodic flow bursts in the nightside are presented. The flow bursts closely resemble single radar observations reported by Williams et al. By using the Polar Anglo-American Conjugate Experiment (PACE) HF radar array at Halley Bay in conjunction with the EISCAT Common Program (CP) 2-D experiment, the flow bursts are shown to be a global phenomenon and important information as to their development and propagation can be determined
Potassium bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)bis(4,4,4-trifluoro-1-phenylbutane-1,3-dionato)europate(III)
In the crystal structure of the title complex, K[Eu(C5HF6O2)2(C10H6F3O2)2], the EuIII ion is in a slightly distorted square-antiprismatic coordination geometry which is defined by eight O atoms of the anionic β-diketone ligands. The two K+ ions lie on crystallographic inversion centers. The Eu—O bond distances are in the range 2.294 (5)–2.413 (5) Å. The crystal used was a non-merohedral twin, the ratio of the twin domains being 0.5236 (5):0.4764 (5)
Combined Multipoint Remote and In Situ Observations of the Asymmetric Evolution of a Fast Solar Coronal Mass Ejection
We present an analysis of the fast coronal mass ejection (CME) of 2012 March
7, which was imaged by both STEREO spacecraft and observed in situ by
MESSENGER, Venus Express, Wind and Mars Express. Based on detected arrivals at
four different positions in interplanetary space, it was possible to strongly
constrain the kinematics and the shape of the ejection. Using the white-light
heliospheric imagery from STEREO-A and B, we derived two different kinematical
profiles for the CME by applying the novel constrained self-similar expansion
method. In addition, we used a drag-based model to investigate the influence of
the ambient solar wind on the CME's propagation. We found that two preceding
CMEs heading in different directions disturbed the overall shape of the CME and
influenced its propagation behavior. While the Venus-directed segment underwent
a gradual deceleration (from ~2700 km/s at 15 R_sun to ~1500 km/s at 154
R_sun), the Earth-directed part showed an abrupt retardation below 35 R_sun
(from ~1700 to ~900 km/s). After that, it was propagating with a quasi-constant
speed in the wake of a preceding event. Our results highlight the importance of
studies concerning the unequal evolution of CMEs. Forecasting can only be
improved if conditions in the solar wind are properly taken into account and if
attention is also paid to large events preceding the one being studied
STEREO and Wind observations of a fast ICME flank triggering a prolonged geomagnetic storm on 5-7 April 2010
On 5 April 2010 an interplanetary (IP) shock was detected by the Wind
spacecraft ahead of Earth, followed by a fast (average speed 650 km/s) IP
coronal mass ejection (ICME). During the subsequent moderate geomagnetic storm
(minimum Dst = -72 nT, maximum Kp=8-), communication with the Galaxy 15
satellite was lost. We link images from STEREO/SECCHI to the near-Earth in situ
observations and show that the ICME did not decelerate much between Sun and
Earth. The ICME flank was responsible for a long storm growth phase. This type
of glancing collision was for the first time directly observed with the STEREO
Heliospheric Imagers. The magnetic cloud (MC) inside the ICME cannot be modeled
with approaches assuming an invariant direction. These observations confirm the
hypotheses that parts of ICMEs classified as (1) long-duration MCs or (2)
magnetic-cloud-like (MCL) structures can be a consequence of a spacecraft
trajectory through the ICME flank.Comment: Geophysical Research Letters (accepted); 3 Figure
The optimisation of fingermark enhancement by VMD and Lumicyano™ on thermal paper
The enhancement of fingermarks on thermal paper can be challenging due to background staining caused by polar solvents used in fingermark enhancement techniques such as ninhydrin. This study explored a commercial one-step superglue fuming process, Lumicyano™, and Vacuum Metal Deposition (VMD) to develop fingermarks on this substrate and overcome this issue. Different sequential treatments involving Lumicyano™ and a combination of VMD methods were investigated with varying degrees of success with some sequences being highly sensitive. The VMD processes, however, were observed to generally be more effective at enhancing marks, whereas Lumicyano™ provided little or no benefit on this paper type. The results indicate that Lumicyano™ is only beneficial as a pre-treatment when the entire sequence of gold/zinc and silver/zinc is taken to completion. The gold/zinc and silver/zinc VMD processes were optimised on five different thermal papers, and the optimised techniques were then directly compared to determine which was more successful on each thermal paper type as a single treatment
Mast cells produce a unique chondroitin sulfate epitope
The granules of mast cells contain a myriad of mediators that are stored and protected by the sulfated glycosaminoglycan (GAG) chains that decorate proteoglycans. Whereas heparin is the GAG predominantly associated with mast cells, mast cell proteoglycans are also decorated with heparan sulfate and chondroitin sulfate (CS). This study investigated a unique CS structure produced by mast cells that was detected with the antibody clone 2B6 in the absence of chondroitinase ABC digestion. Mast cells in rodent tissue sections were characterized using toluidine blue, Leder stain and the presence of mast cell tryptase. The novel CS epitope was identified in rodent tissue sections and localized to cells that were morphologically similar to cells chemically identified as mast cells. The rodent mast cell-like line RBL-2H3 was also shown to express the novel CS epitope. This epitope co-localized with multiple CS proteoglycans in both rodent tissue and RBL-2H3 cultured cells. These findings suggest that the novel CS epitope that decorates mast cell proteoglycans may play a role in the way these chains are structured in mast cells
Dichlorido(3,5-dimethyl-1H-pyrazole)[(3,5-dimethyl-1H-pyrazol-1-yl)(o-tolyl)methanone]palladium(II)
In the title compound, [PdCl2(C5H8N2)(C12H12N2O)], the Pd atom adopts a slightly distorted trans-PdCl2N2 square-planar arrangement. The different Pd—N bond lengths can be related to the the electron-withdrawing effect of the o-toluoyl group on the substituted pyrazole ligand. The complex crystallizes as centrosymmetric hydrogen-bonded dimers through N—H⋯Cl linkages
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