948 research outputs found
On the vertical distribution of seers and other commercially important fishes in the surface drift nets
This note highlights the author's attempts to determine the vertical height for catching seers (Scomberomorus sp.) and other commercially important fish off Kakinada coast
X-Ray Bursts from the Galactic X-Ray Transient Source GRS 1915+105
We have analyzed publicly available RXTE/PCAs archival data of GRS 1915+105
during its burst/flaring state. The burst cycle ranges from 30 to 1300 s. These
bursts are different from the type I and type II classical bursts seen in Low
Mass X-ray Binaries (LMXBs) in terms of their temporal and spectral properties.
We have classified these bursts on the basis of properties observed during the
quiescent (low flux) phase. The 2 - 10 Hz QPOs are present during the quiescent
phase and disappear during the burst phase of all types of these X-ray bursts.
The duration of the quiescent phase can be explained assuming an outflow from
the post-shock regions and the catastrophic Compton cooling.Comment: 5 pages with two figures, 33rd COSPAR, Warsaw, Poland, July 16-22,
200
Effect of colour on the catch of gill nets
The effect of white, green, blue and yellow coloured drift gill nets on their catch with respect to Scomberomorus guttatus (Schneider), Scomberomorus commerson (Lacepede), Scomberomorus lineolatus (Cuvier), Parastomateus niger (Bloch), Euthynnus ajjinis (Cantor) and sharks Carcharius melanopterus is discussed. White nets were more effective for S. guttatus while the coloured ones caught more of P. niger. Blue had no significant effect for sharks. In the case of S. lineolatus, S. commerson and E. affinis no preference to colour was noted
X-ray variability of GRS 1915+105 during the low-hard state observed with the Indian X-ray astronomy experiment (IXAE)
The galactic superluminal transient X-ray source GRS 1915+105 was observed
with the pointed proportional counters (PPCs) onboard the Indian satellite
IRS-P3 during 1996 July 23-27. We report here details of the behavior of this
source during the relatively quiet and low luminosity state. Large intensity
variations by a factor of 2 to 3, generally seen in black-hole candidates, are
observed at a time scale of 100 ms to few seconds. No significant variation is
detected over larger time scale of minute or more. The intensity variations are
described as sum of shots in the light curve, and the number distribution of
the shots are found to be exponential function of the fluence and duration of
the shots. The cross correlation spectrum between 6-18 keV and 2-6 keV X-rays
is found to have asymmetry signifying a delay of the hard X-rays by about 0.2
to 0.4 sec. This supports the idea of hard X-rays being generated by Compton
up-scattering from high energy clouds near the source of soft X-rays. Very
strong and narrow quasi periodic oscillations in the frequency range 0.62 to
0.82 Hz are observed. We discuss about a model which explains a gradual change
in the QPO frequencies with corresponding changes in the mass accretion rate of
the disk.Comment: 14 pages including 6 figures. To appear in Astronomy and Astrophysics
Supplement Serie
Generation of ultrashort electrical pulses in semiconductor waveguides
We report a novel device capable of generating ultrashort electrical pulses on a coplanar waveguide (CPW) by means of optical rectification. The device consists of a completely passive GaAs-based optical waveguide, which is velocity matched to a CPW line. Optical pulses are injected into the device and electrical pulses are collected at the output. Experimental results obtained in the laboratory show the potential of this device for high speed optical-to-electrical conversion
Mesh selectivity for spotted seer, Scomberomorus guttatus (Bloch & Schneider)
An attempt has been made to evolve a suitable mesh size for the commercially significant size group of S. guttatus. To obtain maximum sustainable yield taking biological factors also into consideration, 52 mm mesh bar nets are suggested for exploiting the fishery on both the East coasts of India
Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO
Optical conductivity spectra of paramagnetic CaRuO are
investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid
behavior of , similar to the case
of a ferromagnet SrRuO. As the temperature () is increased, on the other
hand, in the low frequency region is progressively
suppressed, deviating from the 1/{\omega}^{\frac 12%}-dependence.
Interestingly, the suppression of is found to scale with
at all temperatures. The origin of the scaling
behavior coupled with the non-Fermi liquid behavior is discussed.Comment: 4 pages, 3 figure
A Hybrid Artificial Bee Colony Algorithm for Graph 3-Coloring
The Artificial Bee Colony (ABC) is the name of an optimization algorithm that
was inspired by the intelligent behavior of a honey bee swarm. It is widely
recognized as a quick, reliable, and efficient methods for solving optimization
problems. This paper proposes a hybrid ABC (HABC) algorithm for graph
3-coloring, which is a well-known discrete optimization problem. The results of
HABC are compared with results of the well-known graph coloring algorithms of
today, i.e. the Tabucol and Hybrid Evolutionary algorithm (HEA) and results of
the traditional evolutionary algorithm with SAW method (EA-SAW). Extensive
experimentations has shown that the HABC matched the competitive results of the
best graph coloring algorithms, and did better than the traditional heuristics
EA-SAW when solving equi-partite, flat, and random generated medium-sized
graphs
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