376 research outputs found
Statistics of Flares Sweeping across Sunspots
Flare ribbons are always dynamic, and sometimes sweep across sunspots.
Examining 588 (513 M-class and 75 X-class) flare events observed by Transition
Region and Coronal Explorer (TRACE) satellite and Hinode Solar Optical
Telescope (SOT) from 1998 May to 2009 May, we choose the event displaying that
one of the flare ribbons completely sweeps across the umbra of a main sunspot
of the corresponding active region, and finally obtain 20 (7 X-class and 13
M-class) events as our sample. In each event, we define the main sunspot
completely swept across by the flare ribbon as A-sunspot, and its nearby
opposite polarity sunspots, B-sunspot. Observations show that the A-sunspot is
a following polarity sunspot in 18 events, and displays flux emergence in 13
cases. All the B-sunspots are relatively simple, exhibiting either one main
sunspot or one main sunspot and several small neighboring sunspots (pores). In
two days prior to the flare occurrence, the A-sunspot rotates in all the cases,
while the B-sunspot, in 19 events. The total rotating angle of the A-sunspot
and B-sunspot is 193 degrees on average, and the rotating directions, are the
same in 12 events. In all cases, the A-sunspot and B-sunspot manifest shear
motions with an average shearing angle of 28.5 degrees, and in 14 cases, the
shearing direction is opposite to the rotating direction of the A-sunspot. We
suggest that the emergence, the rotation and the shear motions of the A-sunspot
and B-sunspot result in the phenomenon that flare ribbons sweep across sunspots
completely.Comment: 12 pages, 3 figures, 2 tables, accepted by ApJ Letter
Influences of condensational process in the middle troposphere on developing of a summer Arctic cyclone
第6回極域科学シンポジウム[OM] 極域気水圏11月16日(月) 国立極地研究所1階交流アトリウ
Two Types of Dynamic Cool Coronal Structures Observed with STEREO and HINODE
Solar coronal loops show significant plasma motions during their formation
and eruption stages. Dynamic cool coronal structures, on the other hand, are
often observed to propagate along coronal loops. In this paper, we report on
the discovery of two types of dynamic cool coronal structures, and characterize
their fundamental properties. Using the EUV 304 angstrom images from the
Extreme UltraViolet Imager (EUVI) telescope on the Solar TErrestrial RElation
Observatory (STEREO) and the Ca II filtergrams from the Solar Optical Telescope
(SOT) instrument on HINODE, we study the evolution of an EUV arch and the
kinematics of cool coronal structures. The EUV 304 angstrom observations show
that a missile-like plasmoid moves along an arch-shaped trajectory, with an
average velocity of 31 km/s. About three hours later, a plasma arch forms along
the trajectory, subsequently the top part of the arch fades away and
disappears, meanwhile the plasma belonging to the two legs of the arch flows
downward to the arch feet. During the arch formation and disappearance, SOT Ca
II images explore dynamic cool coronal structures beneath the arch. By tracking
these structures, we classify them into two types. Type I is threadlike in
shape and flows downward with a greater average velocity of 72 km/s, finally it
combines a loop fibril at chromospheric altitude. Type II is
shape-transformable and sometimes rolling as it flows downward with a smaller
velocity of 37 km/s, then disappears insularly in the chromosphere. It is
suggested that the two types of structures are possibly controlled by different
magnetic configurations.Comment: 13 pages, 7 figures, accepted by RA
Multivariate stochastic volatility
Published in Econometric Reviews, 2006. https://doi.org/10.1080/07474930600713564</p
Observations of The Magnetic Reconnection Signature of An M2 Flare on 2000 March 23
Multi-wavelength observations of an M 2.0 flare event on 2000 March 23 in
NOAA active region 8910 provide us a good chance to study the detailed
structure and dynamics of the magnetic reconnection region. In the process of
the flare, extreme ultraviolet (EUV) loops displayed two times of sideward
motions upon a loop-top hard X-ray source with average velocities of 75 and
25.6 km/s, respectively. We consider these two motions to be the observational
evidence of reconnection inflow, and find an X-shaped structure upon the
post-flare loops during the period of the second motion. Two separations of the
flare ribbons are associated with these two sideward motions, with average
velocities of 3.3 and 1.3 km/s, separately. Using the observation of
photospheric magnetic field, the velocities of the sideward motions and the
separations, we deduce the corresponding coronal magnetic field strength to be
about 13.2-15.2 G, and estimate the reconnection rates to be 0.05 and 0.02 for
these two magnetic reconnection processes, respectively. We also observe
motions of bright points upward and downward along the EUV loops with
velocities ranging from 45.4 to 556.7 km/s. A cloud of bright material flowing
outward from the loop-top hard X-ray source with an average velocity of 51 km/s
in the process of the flare may be accelerated by the tension force of the
newly reconnected magnetic field lines. All the observations can be explained
by schematic diagrams of magnetic reconnection.Comment: 19 pages, 6 figures, accepted by Ap
744-3 Inhibition of Nitric Oxide Synthesis does not Increase Cardiac Contractile Response but Reduces Coronary Blood Flow Response to β-Adrenergic Stimulation in Normal Dogs
Although the induction of nitric oxide (NO) synthesis has been implicated as a cause of cytokine-induced depression of cardiac β-adrenergic responsiveness. whether the NO system constitutively present in the normal myocardium plays a role in its physiologic response to β-adrenergic stimulation in vivoremains controversial. Accordingly, we examined the effects of low and high doses of NW-nitro-L-arginine methyl ester (L-NAME)(10 and 100 μg/kg/min for 10 min), an NO synthase inhibitor, administered into left circumflex coronary artery (LCX) on responses of peak left ventricular (LV) dP/dt, regional wall thickening in LCX region and LCX blood flow to graded intracoronary (IC) doses of isoproterenol (ISO:0.002 to 0.016 μg/kg/min) in 7 anesthetized dogs. IC L-NAME was associated with dose-related reductions in IC acetylcholine-induced coronary vasodilation. Effects of L-NAME on ISO-induced changes are shown:baselineISO:0.0020.0040.008.0016Peak LV dP/dt (mmHg/sec) (n=7)control2029±1362586±1922820±2003309±2554120±419*low L-NAME2171±1492566±1762894±2063214±2233707±250*high L-NAME2114±1662326±1932560±1523014±1403354±171*Wall thickening (%) (n=2)control22±725±629±533±735±9low L-NAME25±1125±1528±1931±1836±21high L-NAME28±1725±1525±1531±1934±15LCX blood flow (ml/min)(n=7)control33±648±752±661±870±9*low L-NAME36±741±844±947±852±9*high L-NAME33±736±838±740±748±8*mean ± SEM*p<0.05Thus, inhibition of NO synthesis by L-NAME did not change baseline contractility nor did it increase its response to ISO. It also did not alter baseline blood flow, but reduced significantly its response to ISO. These data strongly suggest that the NO system in the normal myocardium does not modulate contractility, but NO formation in the vasculature contributes to the β-adrenergic coronary vasodilation
On the Brightening Propagation of Post-Flare Loops Observed by TRACE
Examining flare data observed by TRACE satellite from May 1998 to December
2006, we choose 190 (151 M-class and 39 X-class) flare events which display
post-flare loops (PFLs), observed by 171 \AA and 195 \AA wavelengths. 124 of
the 190 events exhibit flare ribbons (FRs), observed by 1600 \AA images. We
investigate the propagation of the brightening of these PFLs along the neutral
lines and the separation of the FRs perpendicular to the neutral lines. In most
of the cases, the length of the FRs ranges from 20 Mm to 170 Mm. The
propagating duration of the brightening is from 10 to 60 minutes, and from 10
minutes to 70 minutes for the separating duration of the FRs. The velocities of
the propagation and the separation range from 3 km/s to 39 km/s and 3 km/s to
15 km/s, respectively. Both of the propagating velocities and the separating
velocities are associated with the flare strength and the length of the FRs. It
appears that the propagation and the separation are dynamically coupled, that
is the greater the propagating velocity is, the faster the separation is.
Furthermore, a greater propagating velocity corresponds to a greater
deceleration (or acceleration). These PFLs display three types of propagating
patterns. Type I propagation, which possesses about half of all the events, is
that the brightening begins at the middle part of a set of PFLs, and propagates
bi-directionally towards its both ends. Type II, possessing 30%, is that the
brightening firstly appears at one end of a set of PFLs, then propagates to the
other end. The remnant belongs to Type III propagation which displays that the
initial brightening takes place at two (or more than two) positions on two (or
more than two) sets of PFLs, and each brightening propagates bi-directionally
along the neutral line.Comment: 13 pages, 11 figures, APJ in pres
Convolutional neural network can recognize drug resistance of single cancer cells
It is known that single or isolated tumor cells enter cancer patients' circulatory systems. These circulating tumor cells (CTCs) are thought to be an effective tool for diagnosing cancer malignancy. However, handling CTC samples and evaluating CTC sequence analysis results are challenging. Recently, the convolutional neural network (CNN) model, a type of deep learning model, has been increasingly adopted for medical image analyses. However, it is controversial whether cell characteristics can be identified at the single-cell level by using machine learning methods. This study intends to verify whether an AI system could classify the sensitivity of anticancer drugs, based on cell morphology during culture. We constructed a CNN based on the VGG16 model that could predict the efficiency of antitumor drugs at the single-cell level. The machine learning revealed that our model could identify the effects of antitumor drugs with ~0.80 accuracies. Our results show that, in the future, realizing precision medicine to identify effective antitumor drugs for individual patients may be possible by extracting CTCs from blood and performing classification by using an AI system
Podoplanin: An Emerging Cancer Biomarker and Therapeutic Target
Podoplanin (PDPN) is a transmembrane receptor glycoprotein that is upregulated on transformed cells, cancer associated fibroblasts and inflammatory macrophages that contribute to cancer progression. In particular, PDPN increases tumor cell clonal capacity, epithelial mesenchymal transition, migration, invasion, metastasis and inflammation. Antibodies, CAR-T cells, biologics and synthetic compounds that target PDPN can inhibit cancer progression and septic inflammation in preclinical models. This review describes recent advances in how PDPN may be used as a biomarker and therapeutic target for many types of cancer, including glioma, squamous cell carcinoma, mesothelioma and melanoma
A Case of Paragonimus westermani Infection by Eating Imperfectly Cooked Wild Boar Flesh
A 19 year old woman was admitted because of abnormal chest X-ray showing smoothly outlined cystic lesion. The eggs of Paragonimus westermani was identified in the broncho-alveolar lavage fluid. Anti-Paragonimus westermani antibody was positive in the serum by the ELISA method. Six eggs were observed in one gram of feces before the administration of praziquantel. Praziquantel (75mg/kg) was administered for two day, the egg of Paragonimus westermani disappeared in the feces and the size of cystic lesion in the chest X-ray decreased
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