3,243 research outputs found
Fine structures in the atmosphere above a sunspot umbra
We present simultaneous photospheric and chromospheric observations of the
trailing sunspot in NOAA 10904, obtained with the Swedish Solar Telescope (SST)
La Palma, Canary Islands. Time series of high resolution \ion{Ca}{ii}\,
images show transient jet-like structures in sunspot umbrae are elongated,
which we call umbral microjets. These jets are directed roughly parallel to
nearby penumbral microjets, suggesting that they are aligned with the
background magnetic field. In general, first a bright dot-like structure
appears, from which a jet later emerges, although some jets appear without an
associated chromospheric dot. Bright photospheric umbral dots are associated
with umbral microjets arising in the outer umbra. Nevertheless, a one-to-one
correspondence between jet-like events and underlying umbral dots is not seen.
They are typically less than 1\arcsec ~long and less than 0\farcs3 wide. The
typical lifetime of umbral microjets is around one minute. The brightness of
these structures increases from the center of the umbra towards the
umbra-penumbra boundary along with the brightness of the local background.Comment: 5 pages, 6 figures. Accepted for publication in A&A Lette
Morphology and evolution of umbral dots and their substructures
Substructures - dark lanes and tails - of umbral dots (UDs) were predicted by
numerical simulations of magnetoconvection. We analyse a 6 h 23 min time series
of broadband images of a large umbra in the active region NOAA 10634, acquired
with the 1-m Swedish Solar Telescope, in the wavelength band around 602 nm. A
43 min part of this series was reconstructed with the MFBD method, reaching a
spatial resolution of 0.14". We measure brightness, size, lifetime, and
horizontal velocities of various umbral structures. Most (90 %) of UDs and
bright point-like features in faint LBs split and merge, and their median
lifetimes are 3.5 or 5.7 min, depending on whether the split or merge event is
considered as the end of their life. Both UDs and features in faint LBs that do
not split or merge are clearly smaller (0.15") than the average size (0.17") of
all features. Horizontal motions of umbral bright small-scale features are
directed either into the umbra or along faint LBs with mean horizontal
velocities of 0.34 km/s. Features faster than 0.4 km/s appear mostly at the
periphery of the umbra. The intensity of dark lanes, measured in four bright
central UDs (CUDs), is by a factor 0.8 lower than the peak intensity of CUDs.
The width of dark lanes is probably less than the resolution limit 0.14". The
characteristic time of substructure changes of UDs is ~4 min. We observe narrow
(0.14") bright and dark filaments connected with PUDs. Usually one dark and two
bright filaments form a 0.4" wide tail attached to one PUD, resembling a short
dark-cored penumbral filament. Our results indicate the similarity between PUDs
and PGs located at the tips of bright penumbral filaments. The features seen in
numerical MHD simulations are consistent with our observations of dark lanes in
CUDs and tails attached to PUDs.Comment: 8 pages, 8 figures, Astronomy & Astrophysics, in pres
Waves as the source of apparent twisting motions in sunspot penumbrae
The motion of dark striations across bright filaments in a sunspot penumbra
has become an important new diagnostic of convective gas flows in penumbral
filaments. The nature of these striations has, however, remained unclear. Here
we present an analysis of small scale motions in penumbral filaments in both
simulations and observations. The simulations, when viewed from above, show
fine structure with dark lanes running outwards from the dark core of the
penumbral filaments. The dark lanes either occur preferentially on one side or
alternate between both sides of the filament. We identify this fine structure
with transverse (kink) oscillations of the filament, corresponding to a
sideways swaying of the filament. These oscillations have periods in the range
of 5-7 min and propagate outward and downward along the filament. Similar
features are found in observed G-band intensity time series of penumbral
filaments in a sunspot located near disk center obtained by the Broadband
Filter Imager (BFI) on board {\it Hinode}. We also find that some filaments
show dark striations moving to both sides of the filaments. Based on the
agreement between simulations and observations we conclude that the motions of
these striations are caused by transverse oscillations of the underlying bright
filaments.Comment: Accepted for publication in Astrophysical Journal on 8th April 201
Mud banks fishery estimates
Most of the natural processes are common to all coastlines and their physico-chemical
characteristics are quite well known. But, there are some localised and seasonal process,
have significant role in socio-economic benefit of coastal habitant and require continuous
study to understand for sustainable exploration. Mud banks are such an inquisitive coastal
phenomenon which occurs only at a few locations in the nearshore waters of the world
ocean. Muddy shores and adjacent shore faces are found along several open coasts of the
world including south west coast of India. They are generally associated with the dispersal
pathways of rivers that discharge large quantities of fine-grained sediment. The high mud
supply also has considerable coastal ecological and economic impacts on several coastal
countries
A Study on the Effect of Enterprise Resource Planning (ERP) on People of an Organization
The ultimate objective of any organizational initiative to install ERP system is to reveal some advantage, whether it is associated with cost savings, improved efficiencies, or better decision-making. These systems can in the long run save millions of dollars, improve quality of information, and increase workers’ productivity by reducing the amount of time to do a job. ERP systems can virtually eliminate the redundancies that occur from outdated and disparate systems that may be present in each department of an organization. This paper highlights the effect of ERP systems on the people of an organization. The results indicated that employees, customers and suppliers were benefitted due to installation of ERP systems while external agencies were not affected due to ERP systems
Pineal proteins upregulate specific antioxidant defense systems in the brain
The neuroendocrine functions of the pineal affect a wide variety of glandular and nervous system processes. Beside melatonin (MEL), the pineal gland secretes and expresses certain proteins essential for various physiological functions. It has been suggested that the pineal gland may also have an antioxidant role due to secretory product other than MEL. Therefore, the present study was designed to study the effect of buffalo (Bubalus bubalis) pineal proteins (PP) on the antioxidant defense system in the brain of female rats. The twenty-four rats were taken in present study and were divided into four groups: control (0 day), control (28 day), vehicle control and buffalo PP. The PP was injected 100 µg/kg BW intraperitoneal (i.p.) daily for 28 days. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR) and reduced glutathione (GSH) concentration and the levels of lipid peroxidation (LPO) in the brain tissue were measured to assess the antioxidant systems. These enzymes protect from adverse effects of free radicals and help in amelioration of oxidative stress. Buffalo pineal proteins administration did not cause any effect on brain LPO, whereas GPx, GR and GSH were significantly (p < 0.05) decreased. However, SOD and CAT activities were increased to significant levels than the control in PP treated rats. Our study herein suggested that buffalo (Bubalus bubalis) pineal proteins upregulates specific antioxidant defense systems and can be useful in control of various oxidative stress-induced neuronal diseases
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