In the current study, molecular, biological, and antigenic analyses were performed to characterize Border disease virus (BDV) strain FNK2012-1 isolated from a pig in 2012 in Japan. The complete genome comprises 12,327 nucleotides (nt), including a large open reading frame of 11,685 nt. Phylogenetic analysis revealed that FNK2012-1 was clustered into BDV genotype 1 with ovine strains. FNK2012-1 grew in porcine, bovine, and ovine primary cells and cell lines, but grew better in bovine and ovine cells than in porcine cells. Specific pathogen-free pigs inoculated with FNK2012-1 did not show any clinical signs. Noninoculated contact control pigs also did not show clinical signs and did not seroconvert. The results suggest that FNK2012-1 may be of ruminant origin and is poorly adapted to pigs. Such observations can provide important insights into evidence for infection and transmission of BDV, which may be of ruminant origin, among pigs.
The angular dependence of light scattered by dust aggregates has been investigated by means of the discrete dipole method. Two types of aggregates have been treated; BPCA and BCCA whose fractal dimensions are ∼3 and ∼2 in the limit of large size respectively, and whose number of constituent particles range from N=256 to 4096. The radii of constituent particles are 0.01 μm and are partly 0.03 μm. Two kinds of minerals are considered as the constituents; silicate and magnetite. The calculations have been carried out at the wavelength λ=0.6 μm. The angular dependence of the degree of linear polarization and the scattered intensity is sensitive to the structure as well as the chemical composition with increasing size of the aggregates
We investigate the evolution of dust that formed at Population III supernova (SN) explosions and its processing through the collisions with the reverse shocks resulting from the interaction of the SN ejecta with the ambient medium. In particular, we investigate the transport of the shocked dust within the SNR and its effect on the chemical composition, the size distribution, and the total mass of dust surviving in SNRs. We find that the evolution of the reverse shock, and hence its effect on the processing of the dust, depends on the thickness of the envelope retained by the progenitor star. Furthermore, the transport and survival of the dust grains depend on their initial radius, aini, and composition: for Type II SNRs expanding into the ISM with a density of nH,0 = 1 cm-3, small grains with aini ≲ 0.05 μm are completely destroyed by sputtering in the postshock flow, while grains with aini = 0.05-0.2 μm are trapped into the dense shell behind the forward shock. Very large grains of aini ≳ 0.2 μm are ejected into the ISM without decreasing their sizes significantly. We find that the total mass fraction of dust that is destroyed by the reverse shock ranges from 0.2 to 1.0, depending on the energy of the explosion and the density of the ambient ISM. The results of our calculations have significant impact on the abundance pattern of the second-generation stars that form in the dense shell of primordial SNRs.
A few particles of presolar Al2O3 grains with sizes above 0.5 mum are believed to have been produced in the ejecta of core-collapse supernovae (SNe). In order to clarify the formation condition of such large Al2O3 grains, we investigate the condensation of Al2O3 grains for wide ranges of the gas density and cooling rate. We first show that the average radius and condensation efficiency of newly formed Al2O3 grains are successfully described by a non-dimensional quantity "Lambda_on" defined as the ratio of the timescale with which the supersaturation ratio increases to the collision timescale of reactant gas species at dust formation. Then, we find that the formation of submicron-sized Al2O3 grains requires at least ten times higher gas densities than those presented by one-dimensional SN models. This indicates that presolar Al2O3 grains identified as a SN origin might be formed in dense gas clumps, allowing us to propose that the measured sizes of presolar grains can be a powerful tool to constrain the physical conditions in which they formed. We also briefly discuss the survival of newly formed Al2O3 grains against the destruction in the shocked gas within the SN remnants.
The process of homogeneous nucleation and grain growth is formulated, where the chemical reaction accompanying nucleation and growth is taken into account under the assumption that the rates of nucleation and grain growth are determined by one key molecular species. This theory is applied to the condensation of refractory minerals in a cooling gas of the solar composition. Condensation sequence of refractory minerals and their grain size are presented as a function of the cooling time of gas and the total gas pressure. The formation of refractory grains in sites of astrophysical interest is discussed.
We investigated bulk milk samples form 196 herds in 2 districts of Hokkaido (151 farms from district A and 45 farms from district B) to determine the prevalence of infection with the bovine viral-diarrhea virus (BVDV). The BVDV was detected from a few area-A samples but from none of the area-B samples. The virus-neutralization test conducted to detect BVDV antibodies in bulk-milk whey showed neutralizing-antibody titers (NT) of more than 16 in 166 samples (84.7%). Epidemiological information obtained from 132 of the 166 herds showed that 64 herds (48.5%) had BVDV NT of more than 16. None of these herds, however, had histories of BVDV infection or vaccination; and no animals had been introduced into them from other farms. These results suggest that BVDV prevailed in these areas irrespective of BVDV-gene detection, although the origin of the BVDV infection remained unclear. Therefore, eradicating BVDV from dairy populations may necessitate longterm assessment of herd BVDV infection.
Abstract We develop a magnetohydrodynamical model of Alfvén wave-driven wind in open magnetic flux tubes piercing the stellar surface of red giant branch (RGB) and asymptotic giant branch (AGB) stars, and investigate the physical properties of the winds. The model simulations are carried out along the evolutionary tracks of stars with initial mass in the range of 1.5–3.0 M ⊙ and initial metallicity Z ini = 0.02. Setting the surface magnetic field strength to 1 G, we find that the wind during the evolution of the star can be classified into the following four types: the first is wind with velocity higher than 80 km s −1 in the RGB and early AGB (E-AGB) phases, the second is wind with outflow velocity less than 10 km s −1 seen around the tip of the RGB or in the E-AGB phase, the third is the unstable wind in the E-AGB and thermally pulsing AGB (TP-AGB) phases, and the fourth is the stable massive and slow wind with mass-loss rate higher than 10 −7 M ⊙ yr −1 and outflow velocity lower than 20 km s −1 in the TP-AGB phase. The mass-loss rates in the first and second types of wind are two or three orders of magnitude lower than the values evaluated by an empirical formula. The presence of a massive and slow wind of the fourth type suggests the possibility that the massive outflow observed in TP-AGB stars could be attributed to Alfvén wave-driven wind.
