2,091 research outputs found
Accretion disc-corona and jet emission from the radio-loud narrow-line Seyfert 1 galaxy RX J1633.3+4719
We perform X-ray/ultraviolet (UV) spectral and X-ray variability studies of
the radio-loud narrow-line Seyfert 1 (NLS1) galaxy RX J1633.3+4719 using
XMM-Newton and Suzaku observations from 2011 and 2012. The 0.3-10 keV spectra
consist of an ultrasoft component described by an accretion disc blackbody
(kT_in = 39.6^{+11.2}_{-5.5} eV) and a power law due to the thermal
Comptonization ({\Gamma} = 1.96^{+0.24}_{-0.31}) of the disc emission. The disc
temperature inferred from the soft excess is at least a factor of 2 lower than
that found for the canonical soft excess emission from radio-quiet NLS1s. The
UV spectrum is described by a power law with photon index 3.05^{+0.56}_{-0.33}.
The observed UV emission is too strong to arise from the accretion disc or the
host galaxy, but can be attributed to a jet. The X-ray emission from RX
J1633.3+4719 is variable with fractional variability amplitude =13.5 per cent. In contrast to radio-quiet active galactic nuclei
(AGN), X-ray emission from the source becomes harder with increasing flux. The
fractional rms variability increases with energy and the rms spectrum is well
described by a constant disc component and a variable power-law continuum with
the normalization and photon index being anticorrelated. Such spectral
variability cannot be caused by variations in the absorption and must be
intrinsic to the hot corona. Our finding of possible evidence for emission from
the inner accretion disc, jet and hot corona from RX J1633.3+4719 in the
optical to X-ray bands makes this object an ideal target to probe the disc-jet
connection in AGN.Comment: 12 pages, 11 figures, 3 tables, Published in MNRA
Yield of aerobic rice affected by high temperature stress during summer season -A study from red and laterite zone of West Bengal, India
Field experiment on the performance of aerobic direct seeded rice (ADSR) under red and laterite zone of West Bengal was conducted at Rice Research Station, Bankura, West Bengal, India during summer season, 2012. The experimental soil was sandy loam with acidic in nature (pH: 5.2). The results exhibited that the grain yield (1 t ha-1) of rice in aerobic situation was low. This might be due to high atmospheric temperature during flowering period, which results in poor grain setting in panicle and most of them became chaffy due to spikelet sterility. Ultimately, it produced low grain yield of rice in aerobic situation during summer season due to high temperature at flowering period, grain formation and grain ripening stages. Thus, aerobic rice system of cultivation needed good management practices
Effect of different sources of organic matter on the yield of rice and soil health in red and lateritic zone of West Bengal, India
Field experiment was conducted to study effect of different sources of organic matter on the yield of rice and soil at Rice Research Station, Bankura, West Bengal, India during kharif season of 2009, 2010 and 2011. Average of three years data revealed that inclusion of vermi-compost in the fertilizers schedule of rice cultivation [variety: Swarna (MTU 7029)] increased the grain yield (30.26%) as well as straw yield (32.70%). However higher pH was observed in treatments receiving paddy straw application and organic carbon (%) was also higher in the respective plots where vermi-compost and paddy straw was applied. Regarding available P2O5, there was an increasing trend up to 13-20 kg ha-1 in vermi-compost and green manure applied plots. In case of available K2O, there was a decrease value in all treatments were observed. So there was a positive balance of P and negative balance of K
A multi-wavelength study of star formation activity in the S235 complex
We have carried out an extensive multi-wavelength study to investigate the
star formation process in the S235 complex. The S235 complex has a sphere-like
shell appearance at wavelengths longer than 2 m and harbors an O9.5V type
star approximately at its center. Near-infrared extinction map traces eight
subregions (having A 8 mag), and five of them appear to be
distributed in an almost regularly spaced manner along the sphere-like shell
surrounding the ionized emission. This picture is also supported by the
integrated CO and CO intensity maps and by Bolocam 1.1 mm
continuum emission. The position-velocity analysis of CO reveals an almost
semi-ring like structure, suggesting an expanding H\,{\sc ii} region. We find
that the Bolocam clump masses increase as we move away from the location of the
ionizing star. This correlation is seen only for those clumps which are
distributed near the edges of the shell. Photometric analysis reveals 435 young
stellar objects (YSOs), 59\% of which are found in clusters. Six subregions
(including five located near the edges of the shell) are very well correlated
with the dust clumps, CO gas, and YSOs. The average values of Mach numbers
derived using NH data for three (East~1, East~2, and Central~E) out of
these six subregions are 2.9, 2.3, and 2.9, indicating these subregions are
supersonic. The molecular outflows are detected in these three subregions,
further confirming the on-going star formation activity. Together, all these
results are interpreted as observational evidence of positive feedback of a
massive star.Comment: 28 pages, 15 figures, 3 tables, Accepted for publication in The
Astrophysical Journa
Grain yield of aerobic rice as influenced by seed rate and row spacing in aerobic situation under changed climate
Aerobic rice system is the method of cultivation, where the rice crop is established by direct seeding in un-puddle field. The grain yield of aerobic rice in aerobic situation realized by the farmers is still lower. Among many factors, seed rate and row spacing influence the grain yield of aerobic rice crop. The present investigation was carriedout to study the influence of seed rates and row spacing on grain yield of aerobic rice in aerobic situation, and field experiment was conducted at Rice Research Station, Bankura, West Bengal, India during kharif season of 2011 and 2012. The experimental results exhibited that the highest grain yield (3.40, 3.49 and 3.42 t ha-1 during kharif 2011, kharif 2012 and in pooled value, respectively) was recorded from treatment S2, where seed rate was 30 kg ha-1. Among the different row spacing, the maximum grain yield of 3.47, 3.45 and 3.46 t ha-1 during kharif season of 2011 and 2012 and on pooled basis was obtained with the treatment R1 i.e. 20 cm row spacing. The treatment combination of S2 (seed rate @ 30 kg ha-1) and R1 (20 cm row spacing) recorded the highest grain yield (4.01 t ha-1) of aerobic rice. It was established that the seed rate @ 30 kg ha-1 and 20 cm row spacing was promising for realizing best grain yield of aerobic rice in aerobic condition. It is an important eco-safety tool for tackling the climate change scenario
Pseudo-hermitian interaction between an oscillator and a spin half particle in the external magnetic field
We consider a spin half particle in the external magnetic field which couples
to a harmonic oscillator through some pseudo-hermitian interaction. We find
that the energy eigenvalues for this system are real even though the
interaction is not PT invariant.Comment: Latex, no figs, 8 pages. (To appear in Mod. Phys. Lett. A
Partially Asymmetric Simple Exclusion Model in the Presence of an Impurity on a Ring
We study a generalized two-species model on a ring. The original model [1]
describes ordinary particles hopping exclusively in one direction in the
presence of an impurity. The impurity hops with a rate different from that of
ordinary particles and can be overtaken by them. Here we let the ordinary
particles hop also backward with the rate q. Using Matrix Product Ansatz (MPA),
we obtain the relevant quadratic algebra. A finite dimensional representation
of this algebra enables us to compute the stationary bulk density of the
ordinary particles, as well as the speed of impurity on a set of special
surfaces of the parameter space. We will obtain the phase structure of this
model in the accessible region and show how the phase structure of the original
model is modified. In the infinite-volume limit this model presents a shock in
one of its phases.Comment: Adding more references and doing minor corrections, 16 pages and 3
Eps figure
On Matrix Product States for Periodic Boundary Conditions
The possibility of a matrix product representation for eigenstates with
energy and momentum zero of a general m-state quantum spin Hamiltonian with
nearest neighbour interaction and periodic boundary condition is considered.
The quadratic algebra used for this representation is generated by 2m operators
which fulfil m^2 quadratic relations and is endowed with a trace. It is shown
that {\em not} every eigenstate with energy and momentum zero can be written as
matrix product state. An explicit counter-example is given. This is in contrast
to the case of open boundary conditions where every zero energy eigenstate can
be written as a matrix product state using a Fock-like representation of the
same quadratic algebra.Comment: 7 pages, late
Study on yield potentiality and spatial requirement of rice varieties (Oryza sativa L.) in system of rice intensification (SRI) under red and laterite zone of West Bengal, India
Field experiment was conducted at Rice Research Station, Bankura during kharif season 2009 and 2010 to study the yield potentiality and spatial requirement of rice varieties in system of rice intensification (SRI) under red and laterite zone of West Bengal. The experiment was laid out in a randomized complete block design (RCBD) in a three replications with two rice varieties (Swarna and Lalat). Performances of swarna and lalat varieties in SRI as compared to conventional method of rice cultivation (CMRC) were investigated. Swarna (MTU 7029) has yielded maximum grain yield (6.07, 5.66 and 5.86 t ha-1 during 2009, 2010 and in pooled, respectively) from the treatment T7 (25 × 25 cm spacing) under SRI. Lowest grain yield (3.55, 3.23 and 3.38 t ha-1 during 2009, 2010 and in pooled, respectively) was recorded from treatment T9 (Lalat at 20 × 15 cm spacing) under CMRC. SRI technology has potential in increasing more grain yield, it saves seed requirement and irrigation water and chemical fertilizer considering than conventional method of cultivation. Rice cultivation is more sustainable and profitable for the farmers in SRI under the red and laterite zone of West Bengal
Screening of three promising rice genotypes for rainfed shallow lowlands of red and lateritic areas of West Bengal, India
A field experiment was conducted during kharif 2011-12 at Rice Research Station, Bankura, West Bengal to screen promising rice genotypes suitable for rainfed shallow lowland situation of red and lateritic areas of West Bengal. Among the thirty genotypes of rice tested, only three genotypes gave significantly higher yields over best check variety Swarna sub-1 (5324 kg ha-1). These three promising genotypes of rice were IET 21987 (6898 kg ha-1), IET 21979 (6759 kg ha-1) and IET 21996 (6342 kg ha-1). It is to be noted that IET 21987 is a nomination from Rice Research Station, Bankura, West Bengal. It was nominated to AICRIP trial IVT-RSL during 2010 in the designation of CN 1317-557-56-BNKR 42-2-3
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