9,062 research outputs found

    A blowout jet associated with one obvious extreme-ultraviolet wave and one complicated coronal mass ejection event

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    In this paper, we present a detailed analysis of a coronal blowout jet eruption which was associated with an obvious extreme-ultraviolet (EUV) wave and one complicated coronal mass ejection (CME) event based on the multi-wavelength and multi-view-angle observations from {\sl Solar Dynamics Observatory} and {\sl Solar Terrestrial Relations Observatory}. It is found that the triggering of the blowout jet was due to the emergence and cancellation of magnetic fluxes on the photosphere. During the rising stage of the jet, the EUV wave appeared just ahead of the jet top, lasting about 4 minutes and at a speed of 458 - \speed{762}. In addition, obvious dark material is observed along the EUV jet body, which confirms the observation of a mini-filament eruption at the jet base in the chromosphere. Interestingly, two distinct but overlapped CME structures can be observed in corona together with the eruption of the blowout jet. One is in narrow jet-shape, while the other one is in bubble-shape. The jet-shaped component was unambiguously related with the outwardly running jet itself, while the bubble-like one might either be produced due to the reconstruction of the high coronal fields or by the internal reconnection during the mini-filament ejection according to the double-CME blowout jet model firstly proposed by Shen et al. (2012b), suggesting more observational evidence should be supplied to clear the current ambiguity based on large samples of blowout jets in future studies.Comment: APJ, Accepted October 19, 201

    A new small satellite sunspot triggering recurrent standard- and blowout-coronal jets

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    In this paper,we report a detailed analysis of recurrent jets originated from a location with emerging, canceling and converging negative magnetic field at the east edge of NOAA active region AR11166 from 2011 March 09 to 10. The event presented several interesting features. First, a satellite sunspot appeared and collided with a pre-existing opposite polarity magnetic field and caused a recurrent solar jet event. Second, the evolution of the jets showed blowout-like nature and standard characteristics. Third, the satellite sunspot exhibited a motion toward southeast of AR11166 and merged with the emerging flux near the opposite polarity sunspot penumbra, which afterward, due to flux convergence and cancellation episodes, caused recurrent jets. Fourth, three of the blowout jets associated with coronal mass ejections (CMEs), were observed from field of view of the Solar Terrestrial Relations Observatory. Fifth, almost all the blowout jet eruptions were accompanied with flares or with more intense brightening in the jet base region, while almost standard jets did not manifest such obvious feature during eruptions. The most important, the blowout jets were inclined to faster and larger scale than the standard jets. The standard jets instead were inclined to relative longer-lasting. The obvious shearing and twisting motions of the magnetic field may be interpreted as due to the shearing and twisting motions for a blowout jet eruption. From the statistical results, about 30% blowout jets directly developed into CMEs. It suggests that the blowout jets and CMEs should have a tight relationship.Comment: ApJ 18 pages, 7 figure

    Zika Virus Attenuation by Codon Pair Deoptimization Induces Sterilizing Immunity in Mouse Models.

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    Zika virus (ZIKV) infection during the large epidemics in the Americas is related to congenital abnormities or fetal demise. To date, there is no vaccine, antiviral drug, or other modality available to prevent or treat Zika virus infection. Here we designed novel live attenuated ZIKV vaccine candidates using a codon pair deoptimization strategy. Three codon pair-deoptimized ZIKVs (Min E, Min NS1, and Min E+NS1) were de novo synthesized and recovered by reverse genetics and contained large amounts of underrepresented codon pairs in the E gene and/or NS1 gene. The amino acid sequence was 100% unchanged. The codon pair-deoptimized variants had decreased replication fitness in Vero cells (Min NS1 ≫ Min E > Min E+NS1), replicated more efficiently in insect cells than in mammalian cells, and demonstrated diminished virulence in a mouse model. In particular, Min E+NS1, the most restrictive variant, induced sterilizing immunity with a robust neutralizing antibody titer, and a single immunization achieved complete protection against lethal challenge and vertical ZIKV transmission during pregnancy. More importantly, due to the numerous synonymous substitutions in the codon pair-deoptimized strains, reversion to wild-type virulence through gradual nucleotide sequence mutations is unlikely. Our results collectively demonstrate that ZIKV can be effectively attenuated by codon pair deoptimization, highlighting the potential of Min E+NS1 as a safe vaccine candidate to prevent ZIKV infections.IMPORTANCE Due to unprecedented epidemics of Zika virus (ZIKV) across the Americas and the unexpected clinical symptoms, including Guillain-Barré syndrome, microcephaly, and other birth defects in humans, there is an urgent need for ZIKV vaccine development. Here we provided the first attenuated versions of ZIKV with two important genes (E and/or NS1) that were subjected to codon pair deoptimization. Compared to parental ZIKV, the codon pair-deoptimized ZIKVs were mammal attenuated and preferred insect to mammalian cells. Min E+NS1, the most restrictive variant, induced sterilizing immunity with a robust neutralizing antibody titer and achieved complete protection against lethal challenge and vertical virus transmission during pregnancy. More importantly, the massive synonymous mutational approach made it impossible for the variant to revert to wild-type virulence. Our results have proven the feasibility of codon pair deoptimization as a strategy to develop live attenuated vaccine candidates against flaviviruses such as ZIKV, Japanese encephalitis virus, and West Nile virus

    The implement of plastic oval tags for mark-recapture in juvenile Japanese flounder (Paralichthys olivaceus) on the northeast coast of Shandong Province, China

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    As part of the stock enhancement research project of Shandong Province, China, plastic oval tags (POTs) were used to mark juvenile Japanese flounder for release, Paralichthys olivaceus (70 to 133 mm total length, TL), in 2009 and 2010. Optimal tag placement locations, retention, tagging rates, and mortality were initially evaluated. Mark–recapture experiments were carried out in the coastal waters of Weihai City to study their migratory movements: 21,202 individuals in July 2009 at Beihai and 18,350 individuals in July 2010 at Lidao. The number of recaptured individuals were 434 (2.05% recapture rate) in 2009 and 620 (3.38% recapture rate) in 2010. A radiative movement from the release site was observed in the 2009 experiment; however, the tagging experiment showed a predominantly northward dispersal of tagged flounder from the release site in 2010. The mean movement speed of the released fish was calculated as 0.46 km day-1 in 2009 and 1.05 km day-1 in 2010. Furthermore, in 2009, the average TL and wet mass increments were 36.3 ± 8.4 mm month-1 and 27.13 ± 16.09 g month-1, respectively 1 to 6 months after releasing; however, the increments were 14.7 ± 8.8 mm month-1 and 5.65 ± 4.17 g month-1, respectively in 2010.Key words: Paralichthys olivaceus, plastic oval tag, mark–recapture, movement, growth

    Neutron Scattering Measurements of Spatially Anisotropic Magnetic Exchange Interactions in Semiconducting K0.85Fe1.54Se2 (TN=280 K)

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    We use neutron scattering to study the spin excitations associated with the stripe antiferromagnetic (AFM) order in semiconducting K0.85_{0.85}Fe1.54_{1.54}Se2_2 (TNT_N=280280 K). We show that the spin wave spectra can be accurately described by an effective Heisenberg Hamiltonian with highly anisotropic in-plane couplings at TT= 55 K. At high temperature (TT= 300300 K) above TNT_N, short range magnetic correlation with anisotropic correlation lengths are observed. Our results suggest that, despite the dramatic difference in the Fermi surface topology, the in-plane anisotropic magnetic couplings are a fundamental property of the iron based compounds; this implies that their antiferromagnetism may originate from local strong correlation effects rather than weak coupling Fermi surface nesting.Comment: 5 pages, 4 figure

    Effect of CeO2 addition on hardness of induction heated Ni-WC composite coatings

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    Getting Ni-WC composite coatings with different rare earth CeO2 additions on the substrate of 45 steel by induction heating; testing the surface hardness and cross-section microhardness of the coatings with Rockwell hardness tester and microhardness tester; meanwhile analyzing the microstructure and WC morphology of the coatings by scanning electron microscopy (SEM), in order to find the best amount of CeO2 in the coatings. The results show that the 0,5 / % content of CeO2 helps to improve the interfusion bonding between the coating and the substrate, and to refine the grain size, homogenize the composition and increase the hardness of the coating
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