152 research outputs found
Wave dynamics in a sunspot umbra
The high spatial and time resolution data obtained with SDO/AIA for the
sunspot in active region NOAA 11131 on 08 December 2010 were analysed with the
time-distance plot technique and the pixelised wavelet filtering method.
Oscillations in the 3 min band dominate in the umbra. The integrated spectrum
of umbral oscillations contains distinct narrowband peaks at 1.9 min, 2.3 min,
and 2.8 min. The power significantly varies in time, forming distinct
oscillation trains. The oscillation power distribution over the sunspot in the
horizontal plane reveals that the enhancements of the oscillation amplitude, or
wave fronts, have a distinct structure consisting of an evolving two-armed
spiral and a stationary circular patch at the spiral origin, situated near the
umbra centre. This structure is seen from the temperature minimum to the
corona. In time, the spiral rotates anti-clockwise. The wave front spirality is
most pronounced during the maximum amplitude phases of the oscillations. In the
low-amplitude phases the spiral breaks into arc-shaped patches. The 2D
cross-correlation function shows that the oscillations at higher atmospheric
levels occur later than at lower layers. The phase speed is estimated to be
about 100 km/s. The fine spectral analysis shows that the central patch
corresponds to the high-frequency oscillations, while the spiral arms highlight
the lower-frequency oscillations in the 3-min band. The vertical and horizontal
radial structure of the oscillations is consistent with the model that
interprets umbral oscillations as slow magnetoacoustic waves filtered by the
atmospheric temperature non-uniformity in the presence of the magnetic field
inclination from the vertical. The mechanism for the polar-angle structure of
the oscillations, in particular the spirality of the wave fronts, needs to be
revealed.Comment: 8 pages, 9 figures, Astronomy and Astrophysics, 201
Sunspot waves and flare energy release
We address a possibility of the flare process initiation and further
maintenance of its energy release due to a transformation of sunspot
longitudinal waves into transverse magnetic loop oscillations with initiation
of reconnection. This leads to heating maintaining after the energy release
peak and formation of a flat stage on the X-ray profile. We applied the
time-distance plots and pixel wavelet filtration (PWF) methods to obtain
spatio-temporal distribution of wave power variations in SDO/AIA data. To find
magnetic waveguides, we used magnetic field extrapolation of SDO/HMI
magnetograms. The propagation velocity of wave fronts was measured from their
spatial locations at specific times. In correlation curves of the 17 GHz (NoRH)
radio emission we found a monotonous energy amplification of 3-min waves in the
sunspot umbra before the 2012 June 7 flare. This dynamics agrees with an
increase in the wave-train length in coronal loops (SDO/AIA, 171 {\AA})
reaching the maximum 30 minutes prior to the flare onset. A peculiarity of this
flare time profile in soft X-rays (RHESSI, 3-25 keV) is maintaining the
constant level of the flare emission for 10 minutes after the short impulse
phase, which indicates at the energy release continuation. Throughout this
time, we found 30-sec period transverse oscillations of the flare loop in the
radio-frequency range (NoRH, 17 GHz). This periodicity is apparently related to
the transformation of propagating longitudinal 3-min waves from the sunspot
into the loop transverse oscillations. The magnetic field extrapolation showed
the existence of the magnetic waveguide (loop) connecting the sunspot with the
energy release region. A flare loop heating can be caused by the interaction
(reconnections) of this transversally oscillating waveguide with the underlying
twisted loops.Comment: 7 pages, 9 figure
Quantum uniqueness
In the classical world one can construct two identical systems which have
identical behavior and give identical measurement results. We show this to be
impossible in the quantum domain. We prove that after the same quantum
measurement two different quantum systems cannot yield always identical
results, provided the possible measurement results belong to a non orthogonal
set. This is interpreted as quantum uniqueness - a quantum feature which has no
classical analog. Its tight relation with objective randomness of quantum
measurements is discussed.Comment: Presented at 4th Feynman festival, June 22-26, 2009, in Olomouc,
Czech Republic
Relationship between wave processes in sunspots and quasi-periodic pulsations in active region flares
A phenomenological relationship between oscillations in a sunspot and quasi-periodic pulsations (QPP) in flaring energy releases at an active region (AR) above the sunspot is established. The analysis of the microwave emission recorded by the Nobeyama Radioheliograph at 17 GHz shows a gradual increase in the power of the 3-min oscillation train in the sunspot associated with AR 10756 before flares in this AR. The flaring light curves are found to be bursty with a period of 3 min. Our analysis of the spatial distribution of the 3-min oscillation power implies that the oscillations follow from sunspots along coronal loops towards the flaring site. It is proposed that QPP in the flaring energy releases can be triggered by 3-min slow magnetoacoustic waves leaking from sunspots
Immunometabolism and metainflammation in obesity
Recent studies have shown that immune system cells take an active part in the regulation of metabolic homeostasis. Disruption of the interaction between the immune system and metabolic processes makes a major contribution to the current epidemic of a number of non-communicable metabolic diseases. Due to central and peripheral insulin resistance, obesity is closely associated with type 2 diabetes mellitus. Many mechanisms are involved in the genesis of insulin resistance including chronic inflammation in metabolically active tissues (adipose tissue, intestines, muscles, pancreas, liver), as well as in the central nervous system. Potential triggers of obesity-induced metainflammation are cellular hypoxia, mechanical stress of the fat cells, excess of free fatty acids and lypopolysaccharides. Weight loss is a key factor to eliminating inflammation and improving tissue insulin sensitivity. This review presents literature data on the mechanisms of metainflammation in obesity. Taking into account the contribution of metainflammation to the pathogenesis of the disease, the possibilities and prospects of obesity therapy are discussed
Triplet-like correlation symmetry of continuous variable entangled states
We report on a continuous variable analogue of the triplet two-qubit Bell
states. We theoretically and experimentally demonstrate a remarkable similarity
of two-mode continuous variable entangled states with triplet Bell states with
respect to their correlation patterns. Borrowing from the two qubit language,
we call these correlations triplet-like.Comment: 7 pages, 5 figures. Comments are welcom
- …