1,068 research outputs found
Twisting solar coronal jet launched at the boundary of an active region
A broad jet was observed in a weak magnetic field area at the edge of active
region NOAA 11106. The peculiar shape and magnetic environment of the broad jet
raised the question of whether it was created by the same physical processes of
previously studied jets with reconnection occurring high in the corona. We
carried out a multi-wavelength analysis using the EUV images from the
Atmospheric Imaging Assembly (AIA) and magnetic fields from the Helioseismic
and Magnetic Imager (HMI) both on-board the SDO satellite. The jet consisted of
many different threads that expanded in around 10 minutes to about 100 Mm in
length, with the bright features in later threads moving faster than in the
early ones, reaching a maximum speed of about 200 km s^{-1}. Time-slice
analysis revealed a striped pattern of dark and bright strands propagating
along the jet, along with apparent damped oscillations across the jet. This is
suggestive of a (un)twisting motion in the jet, possibly an Alfven wave. A
topological analysis of an extrapolated field was performed. Bald patches in
field lines, low-altitude flux ropes, diverging flow patterns, and a null point
were identified at the basis of the jet. Unlike classical lambda or
Eiffel-tower shaped jets that appear to be caused by reconnection in current
sheets containing null points, reconnection in regions containing bald patches
seems to be crucial in triggering the present jet. There is no observational
evidence that the flux ropes detected in the topological analysis were actually
being ejected themselves, as occurs in the violent phase of blowout jets;
instead, the jet itself may have gained the twist of the flux rope(s) through
reconnection. This event may represent a class of jets different from the
classical quiescent or blowout jets, but to reach that conclusion, more
observational and theoretical work is necessary.Comment: 12 pages, 9 figures, accepted for publication in A&
Acute Ethanol Administration Rapidly Increases Phosphorylation of Conventional Protein Kinase C in Specific Mammalian Brain Regions in Vivo
Background
Protein kinase C (PKC) is a family of isoenzymes that regulate a variety of functions in the central nervous system including neurotransmitter release, ion channel activity, and cell differentiation. Growing evidence suggests that specific isoforms of PKC influence a variety of behavioral, biochemical, and physiological effects of ethanol in mammals. The purpose of this study was to determine whether acute ethanol exposure alters phosphorylation of conventional PKC isoforms at a threonine 674 (p-cPKC) site in the hydrophobic domain of the kinase, which is required for its catalytic activity.
Methods
Male rats were administered a dose range of ethanol (0, 0.5, 1, or 2 g/kg, intragastric) and brain tissue was removed 10 minutes later for evaluation of changes in p-cPKC expression using immunohistochemistry and Western blot methods.
Results
Immunohistochemical data show that the highest dose of ethanol (2 g/kg) rapidly increases p-cPKC immunoreactivity specifically in the nucleus accumbens (core and shell), lateral septum, and hippocampus (CA3 and dentate gyrus). Western blot analysis further showed that ethanol (2 g/kg) increased p-cPKC expression in the P2 membrane fraction of tissue from the nucleus accumbens and hippocampus. Although p-cPKC was expressed in numerous other brain regions, including the caudate nucleus, amygdala, and cortex, no changes were observed in response to acute ethanol. Total PKC? immunoreactivity was surveyed throughout the brain and showed no change following acute ethanol injection
Fractal Reconnection in Solar and Stellar Environments
Recent space based observations of the Sun revealed that magnetic
reconnection is ubiquitous in the solar atmosphere, ranging from small scale
reconnection (observed as nanoflares) to large scale one (observed as long
duration flares or giant arcades). Often the magnetic reconnection events are
associated with mass ejections or jets, which seem to be closely related to
multiple plasmoid ejections from fractal current sheet. The bursty radio and
hard X-ray emissions from flares also suggest the fractal reconnection and
associated particle acceleration. We shall discuss recent observations and
theories related to the plasmoid-induced-reconnection and the fractal
reconnection in solar flares, and their implication to reconnection physics and
particle acceleration. Recent findings of many superflares on solar type stars
that has extended the applicability of the fractal reconnection model of solar
flares to much a wider parameter space suitable for stellar flares are also
discussed.Comment: Invited chapter to appear in "Magnetic Reconnection: Concepts and
Applications", Springer-Verlag, W. D. Gonzalez and E. N. Parker, eds. (2016),
33 pages, 18 figure
Chromospheric Anemone Jets as Evidence of Ubiquitous Reconnection
The heating of the solar chromosphere and corona is a long-standing puzzle in
solar physics. Hinode observations show the ubiquitous presence of
chromospheric anemone jets outside sunspots in active regions. They are
typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc
second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers
per second. These small jets have an inverted Y-shape, similar to the shape of
x-ray anemone jets in the corona. These features imply that magnetic
reconnection similar to that in the corona is occurring at a much smaller
spatial scale throughout the chromosphere and suggest that the heating of the
solar chromosphere and corona may be related to small-scale ubiquitous
reconnection.Comment: 10 pages, 5 figure
AbMiner: A bioinformatic resource on available monoclonal antibodies and corresponding gene identifiers for genomic, proteomic, and immunologic studies
BACKGROUND: Monoclonal antibodies are used extensively throughout the biomedical sciences for detection of antigens, either in vitro or in vivo. We, for example, have used them for quantitation of proteins on "reverse-phase" protein lysate arrays. For those studies, we quality-controlled > 600 available monoclonal antibodies and also needed to develop precise information on the genes that encode their antigens. Translation among the various protein and gene identifier types proved non-trivial because of one-to-many and many-to-one relationships. To organize the antibody, protein, and gene information, we initially developed a relational database in Filemaker for our own use. When it became apparent that the information would be useful to many other researchers faced with the need to choose or characterize antibodies, we developed it further as AbMiner, a fully relational web-based database under MySQL, programmed in Java. DESCRIPTION: AbMiner is a user-friendly, web-based relational database of information on > 600 commercially available antibodies that we validated by Western blot for protein microarray studies. It includes many types of information on the antibody, the immunogen, the vendor, the antigen, and the antigen's gene. Multiple gene and protein identifier types provide links to corresponding entries in a variety of other public databases, including resources for phosphorylation-specific antibodies. AbMiner also includes our quality-control data against a pool of 60 diverse cancer cell types (the NCI-60) and also protein expression levels for the NCI-60 cells measured using our high-density "reverse-phase" protein lysate microarrays for a selection of the listed antibodies. Some other available database resources give information on antibody specificity for one or a couple of cell types. In contrast, the data in AbMiner indicate specificity with respect to the antigens in a pool of 60 diverse cell types from nine different tissues of origin. CONCLUSION: AbMiner is a relational database that provides extensive information from our own laboratory and other sources on more than 600 available antibodies and the genes that encode the antibodies' antigens. The data will be made freely available a
Multiwavelength Observations of Supersonic Plasma Blob Triggered by Reconnection Generated Velocity Pulse in AR10808
Using multi-wavelength observations of Solar and Heliospheric Observatory
(SoHO)/Michelson Doppler Imager (MDI), Transition Region and Coronal Explorer
(TRACE) 171 \AA, and H from Culgoora Solar Observatory at Narrabri,
Australia, we present a unique observational signature of a propagating
supersonic plasma blob before an M6.2 class solar flare in AR10808 on 9th
September 2005. The blob was observed between 05:27 UT to 05:32 UT with almost
a constant shape for the first 2-3 minutes, and thereafter it quickly vanished
in the corona. The observed lower bound speed of the blob is estimated as
215 km s in its dynamical phase. The evidence of the blob with
almost similar shape and velocity concurrent in H and TRACE 171 \AA\
supports its formation by multi-temperature plasma. The energy release by a
recurrent 3-D reconnection process via the separator dome below the magnetic
null point, between the emerging flux and pre-existing field lines in the lower
solar atmosphere, is found to be the driver of a radial velocity pulse outwards
that accelerates this plasma blob in the solar atmosphere. In support of
identification of the possible driver of the observed eruption, we solve the
two-dimensional ideal magnetohydrodynamic equations numerically to simulate the
observed supersonic plasma blob. The numerical modelling closely match the
observed velocity, evolution of multi-temperature plasma, and quick vanishing
of the blob found in the observations. Under typical coronal conditions, such
blobs may also carry an energy flux of 7.0 ergs cm
s to re-balance the coronal losses above active regions.Comment: Solar Physics; 22 Pages; 8 Figure
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