375 research outputs found

    Statistics of Flares Sweeping across Sunspots

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    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

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    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

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    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

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    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

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    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

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    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&lt;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

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    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

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    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

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    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

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    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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