7,315 research outputs found
First Simultaneous Observation of H-alpha Moreton Wave, EUV Wave, and Filament/Prominence Oscillations
We report on the first simultaneous observation of an H-alpha Moreton wave,
the corresponding EUV fast coronal waves, and a slow and bright EUV wave
(typical EIT wave). Associated with an X6.9 flare that occurred on 2011 August
9 at the active region NOAA 11263, we observed a Moreton wave in the H-alpha
images taken by the Solar Magnetic Activity Research Telescope (SMART) at Hida
Observatory of Kyoto University. In the EUV images obtained by the Atmospheric
Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO) we found
not only the corresponding EUV fast "bright" coronal wave, but also the EUV
fast "faint" wave that is not associated with the H-alpha Moreton wave. We also
found a slow EUV wave, which corresponds to a typical EIT wave. Furthermore, we
observed, for the first time, the oscillations of a prominence and a filament,
simultaneously, both in the H-alpha and EUV images. To trigger the oscillations
by the flare-associated coronal disturbance, we expect a coronal wave as fast
as the fast-mode MHD wave with the velocity of about 570 - 800 km/s. These
velocities are consistent with those of the observed Moreton wave and the EUV
fast coronal wave.Comment: 15 pages, 5 figures, accepted for publication in ApJ
Characterizations of hemirings by their -ideals
In this paper we characterize hemirings in which all -ideals or all fuzzy
-ideals are idempotent. It is proved, among other results, that every
-ideal of a hemiring is idempotent if and only if the lattice of fuzzy
-ideals of is distributive under the sum and -intrinsic product of
fuzzy -ideals or, equivalently, if and only if each fuzzy -ideal of
is intersection of those prime fuzzy -ideals of which contain it. We
also define two types of prime fuzzy -ideals of and prove that, a
non-constant -ideal of is prime in the second sense if and only if each
of its proper level set is a prime -ideal of
Electronic structure of the electron-doped cuprate superconductors
Within the framework of the kinetic energy driven d-wave superconductivity,
the electronic structure of the electron doped cuprate superconductors is
studied. It is shown that although there is an electron-hole asymmetry in the
phase diagram, the electronic structure of the electron-doped cuprates in the
superconducting-state is similar to that in the hole-doped case. With
increasing the electron doping, the spectral weight in the point
increases, while the position of the superconducting quasiparticle peak is
shifted towards the Fermi energy. In analogy to the hole-doped case, the
superconducting quasiparticles around the point disperse very weakly
with momentum.Comment: 8 pages, 3 figures, accepted for publication in Phys. Lett.
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Contribution of particulate nitrate to airborne measurements of total reactive nitrogen
Simultaneous measurements of speciated, total reactive nitrogen (NOy) and particulate NO3 (particle diameter <1.3 μm) were made on board the NASA P-3B aircraft over the western Pacific in February-April 2001 during the Transport and Chemical Evolution over the Pacific (TRACE-P) experiment. Gas-phase and particulate NOy was measured using a gold tube catalytic converter. For the interpretation of particulate NOy, conversion efficiencies of particulate NH4NO3, KNO3, NaNO3, and Ca(NO3)2 were measured in the laboratory. Only NH4NO3 showed quantitative conversion, and its conversion efficiency was as high as that for HNO3. NOy measured on board the aircraft was found to be systematically higher by 10-30% than the sum of the individual NOy gas components (Σ(NOy)i) at 0-4 km. Particulate NO3- concentrations measured by a particle-into-liquid sampler (PILS) were nearly equal to NOy - Σ(NOy)i under low-dust-loading conditions. The PILS data showed that the majority of the particulate NO3- was in the form of NH4NO3 under these conditions, suggesting that NH4NO3 particles were quantitatively converted to detectable NO by the NOy converter, consistent with the laboratory experiments. The contribution of particulate NO3- to NOy was most important at 0-2 km, where NO3- constituted 10-30% of NOy during TRACE-P. On average, the amounts of particulate NO3- and gas-phase HNO3 were comparable in this region. Copyright 2005 by the American Geophysical Union
Hexaaquacobalt(II) 4,4′-(1,2-dihydroxyethane-1,2-diyl)dibenzoate monohydrate
The title compound, [Co(H2O)6](C16H12O6)·H2O, is composed of one 4,4′-(1,2-dihydroxyethane-1,2-diyl)dibenzoate anion lying on an inversion center, one [Co(H2O)6]2+ dicationic complex and a solvent water molecule located on mirror planes. In the crystal, a chain is constructed via O—H⋯O hydrogen bonds involving the carboxylate and hydroxyl groups of the organic anion; the chains are further connected into a three-dimensional framework by additional O—H⋯O hydrogen bonds between the [Co(H2O)6]2+ cations, solvent water molecules and the anions
Sequential Effects in Judgements of Attractiveness: The Influences of Face Race and Sex
In perceptual decision-making, a person’s response on a given trial is influenced by their response on the immediately preceding trial. This sequential effect was initially demonstrated in psychophysical tasks, but has now been found in more complex, real-world judgements. The similarity of the current and previous stimuli determines the nature of the effect, with more similar items producing assimilation in judgements, while less similarity can cause a contrast effect. Previous research found assimilation in ratings of facial attractiveness, and here, we investigated whether this effect is influenced by the social categories of the faces presented. Over three experiments, participants rated the attractiveness of own- (White) and other-race (Chinese) faces of both sexes that appeared successively. Through blocking trials by race (Experiment 1), sex (Experiment 2), or both dimensions (Experiment 3), we could examine how sequential judgements were altered by the salience of different social categories in face sequences. For sequences that varied in sex alone, own-race faces showed significantly less opposite-sex assimilation (male and female faces perceived as dissimilar), while other-race faces showed equal assimilation for opposite- and same-sex sequences (male and female faces were not differentiated). For sequences that varied in race alone, categorisation by race resulted in no opposite-race assimilation for either sex of face (White and Chinese faces perceived as dissimilar). For sequences that varied in both race and sex, same-category assimilation was significantly greater than opposite-category. Our results suggest that the race of a face represents a superordinate category relative to sex. These findings demonstrate the importance of social categories when considering sequential judgements of faces, and also highlight a novel approach for investigating how multiple social dimensions interact during decision-making
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Synoptic-scale transport of reactive nitrogen over the western Pacific in spring
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Impacts of biomass burning in Southeast Asia on ozone and reactive nitrogen over the western Pacific in spring
Aircraft measurements of ozone (O3) and its precursors (reactive nitrogen, CO, nonmethane hydrocarbons) were made over the western Pacific during the Transport and Chemical Evolution Over the Pacific (TRACE-P) campaign, which was conducted during February-April 2001. Biomass burning activity was high over Southeast Asia (SEA) during this period (dry season), and convective activity over SEA frequently transported air from the boundary layer to the free troposphere, followed by eastward transport to the sampling region over the western Pacific south of 30°N. This data set allows for systematic investigations of the chemical and physical processes in the outflow from SEA. Methyl chloride (CH3Cl) and CO are chosen as primary and secondary tracers, respectively, to gauge the degree of the impact of emissions of trace species from biomass burning. Biomass burning is found to be a major source of reactive nitrogen (NO x, PAN, HNO3, and nitrate) and O3 in this region from correlations of these species with the tracers. Changes in the abundance of reactive nitrogen during upward transport are quantified from the altitude change of the slopes of the correlations of these species with CO. NOx decreased with altitude due to its oxidation to HNO3. On the other hand, PAN was conserved during transport from the lower to the middle troposphere, consistent with its low water solubility and chemical stability at low temperatures. Large losses of HNO3 and nitrate, which are highly water soluble, occurred in the free troposphere, most likely due to wet removal by precipitation. This has been shown to be the major pathway of NOy loss in the middle troposphere. Increases in the mixing ratios of O3 and its precursors due to biomass burning in SEA are estimated using the tracers. Enhancements of CO and total reactive nitrogen (NOy), which are directly emitted from biomass burning, were largest at 2-4 km. At this altitude the increases in NOy and O3 were 810 parts per trillion by volume (pptv) and 26 parts per billion by volume (ppbv) above their background values of 240 pptv and 31 ppbv, respectively. The slope of the O3-CO correlation in biomass burning plumes was similar to those observed in fire plumes in northern Australia, Africa, and Canada. The O3 production efficiency (OPE) derived from the O3-CO slope and NOx/CO emission ratio (ER) is shown to be positively correlated with the C2H4 /NOx ER, indicating that the C2H4/NO x ER is a critical parameter in determining the OPE. Comparison of the net O3 flux across the western Pacific region and total O3 production due to biomass burning in SEA suggests that about 70% of O3 produced was transported to the western Pacific. Copyright 2004 by the American Geophysical Union
Photoacid behaviour in a fluorinated green fluorescent protein chromophore:Ultrafast formation of anion and zwitterion states
The photophysics of the chromophore of the green fluorescent protein in Aequorea victoria (avGFP) are dominated by an excited state proton transfer reaction. In contrast the photophysics of the same chromophore in solution are dominated by radiationless decay, and photoacid behaviour is not observed. Here we show that modification of the pKa of the chromophore by fluorination leads to an excited state proton transfer on an extremely fast (50 fs) time scale. Such a fast rate suggests a barrierless proton transfer and the existence of a pre-formed acceptor site in the aqueous solution, which is supported by solvent and deuterium isotope effects. In addition, at lower pH, photochemical formation of the elusive zwitterion of the GFP chromophore is observed by means of an equally fast excited state proton transfer from the cation. The significance of these results for understanding and modifying the properties of fluorescent proteins are discusse
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