10,902 research outputs found
Molecular and phylogenetic characterization of honey bee viruses, Nosema microsporidia, protozoan parasites, and parasitic mites in China
China has the largest number of managed honey bee colonies, which produce the highest quantity of honey and royal jelly in the world; however, the presence of honey bee pathogens and parasites has never been rigorously identified in Chinese apiaries. We thus conducted a molecular survey of honey bee RNA viruses, Nosema microsporidia, protozoan parasites, and tracheal mites associated with nonnative Apis mellifera ligustica and native Apis cerana cerana colonies in China. We found the presence of black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV), but not that of acute bee paralysis virus (ABPV) or Kashmir bee virus (KBV). DWV was the most prevalent in the tested samples. Phylogenies of Chinese viral isolates demonstrated that genetically heterogeneous populations of BQCV, CBPV, DWV, and A. cerana-infecting SBV, and relatively homogenous populations of IAPV and A. meliifera-infecting new strain of SBV with single origins, are spread in Chinese apiaries. Similar to previous observations in many countries, Nosema ceranae, but not Nosema apis, was prevalent in the tested samples. Crithidia mellificae, but not Apicystis bombi was found in five samples, including one A. c. cerana colony, demonstrating that C. mellificae is capable of infecting multiple honey bee species. Based on kinetoplast-encoded cytochrome b sequences, the C. mellificae isolate from A. c. cerana represents a novel haplotype with 19 nucleotide differences from the Chinese and Japanese isolates from A. m. ligustica. This suggests that A. c. cerana is the native host for this specific haplotype. The tracheal mite, Acarapis woodi, was detected in one A. m. ligustica colony. Our results demonstrate that honey bee RNA viruses, N. ceranae, C. mellificae, and tracheal mites are present in Chinese apiaries, and some might be originated from native Asian honey bees
The NuSTAR View of a QPO Evolution of GRS 1915+105
We report a timing analysis of the black hole binary GRS 1915+105 with the
NuSTAR observatory. A strong type-C QPO below 2 Hz appears in the power density
spectrum during the whole observation, whose frequency is correlated with the
3-25 keV count rate. The QPO shows a sudden increase in frequency along with an
increase in flux and a softening of the spectrum. We discuss the possible
origin of the QPO and the reasons that lead to the QPO frequency variation. It
is suggested that the reflection component has little influence on QPO
frequency and the increase in QPO frequency could be associated with the inward
motion of the outer part of the disk.Comment: 21 pages, 8 figures, published in A
Duality relation between coherence and path information in the presence of quantum memory
The wave-particle duality demonstrates a competition relation between wave
and particle behavior for a particle going through an interferometer. This
duality can be formulated as an inequality, which upper bounds the sum of
interference visibility and path information. However, if the particle is
entangled with a quantum memory, then the bound may decrease. Here, we find the
duality relation between coherence and path information for a particle going
through a multipath interferometer in the presence of a quantum memory,
offering an upper bound on the duality relation which is directly connected
with the amount of entanglement between the particle and the quantum memory.Comment: 6 pages, 1 figure, comments are welcom
The accretion rate independence of horizontal branch oscillation in XTE J1701-462
We study the temporal and energy spectral properties of the unique neutron
star low-mass X-ray binary XTE J1701-462. After assuming the HB/NB vertex as a
reference position of accretion rate, the horizontal branch oscillation (HBO)
of the HB/NB vertex is roughly 50 Hz. It indicates that the HBO is independent
with the accretion rate or the source intensity. The spectral analysis shows
in the HB/NB vertex and
in the NB/FB vertex, which
implies that different accretion rate may be produced in the HB/NB vertex and
the NB/FB vertex. The Comptonization component could be fitted by constrained
broken power law (CBPL) or nthComp. Different with GX 17+2, the frequencies of
HBO positively correlate with the inner disk radius, which contradict with the
prediction of Lense-Thirring precession model. XTE J1701-462, both in the
Cyg-like phase and in the Sco-like phase, follows a positive correlation
between the break frequency of broad band noise and the characteristic
frequency of HBO, which is called the W-K relation. An anticorrelation between
the frequency of HBO and photon energy is observed. Moreover, the rms of HBO
increases with photon energy till ~10 keV. We discuss the possible origin of
HBO from corona in XTE J1701-462.Comment: 45 pages, 18 figures, accepted by Ap
Numerical simulations of winds driven by radiation force from the corona above a thin disk
Observations show that winds can be driven from the innermost region (inside
a 50 Schwarschild radius) of a thin disk. It is interesting to study the winds
launched from the innermost region. A hot corona above the black hole (BH) thin
disk is irradiated by the disk. We perform two-dimensional hydrodynamical
simulations to study the winds driven by radiation force from the corona in the
innermost regions. The hard X-ray spectrum from active galactic nuclei (AGNs)
suggests that the corona temperature is about K, so that we mainly
analyze the properties of winds (or outflows) from the K corona. The
disk luminosity plays an important role in driving the outflows. The more
luminous the disk, the stronger the outflows. Mass outflow rate () at a 90 Schwarschild radius depends on disk luminosity, which can be
described as ( is the ratio
of the disk luminosity to the Eddington luminosity). In the case of high
luminosity (e.g. ), the supersonic outflows with maximum speed
Km s are launched at -- and
-- away from the pole axis. The Bernoulli parameter keeps
increasing with the outward propagation of outflows. The radiation force keeps
accelerating the outflows when outflows move outward. Therefore, we can expect
the outflows to escape from the BH gravity and go to the galactic scale. The
interaction between outflows and interstellar medium may be an important AGN
feedback process.Comment: 9 pages, 12 figures, accepted for publication in Ap
- …