251 research outputs found
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
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
Differences in fungal immune recognition by monocytes and macrophages : N-mannan can be a shield or activator of immune recognition
Acknowledgements We thank Professor Gordon Brown for Fc-dectin-1 and Professor David Williams for glucan phosphate. We also thank Kevin MacKenzie, Debbie Wilkinson, Gillian Milne, and Lucy Wright at the University of Aberdeen Core Microscopy & Histology Facility.Peer reviewedPublisher PD
Running spectral index from shooting-star moduli
We construct an inflationary model that is consistent with both large
non-Gaussianity and a running spectral index. The scenario of modulated
inflation suggests that modulated perturbation can induce the curvature
perturbation with a large non-Gaussianity, even if the inflaton perturbation is
negligible. Using this idea, we consider a multi-field extension of the
modulated inflation scenario and examine the specific situation where different
moduli are responsible for the perturbation at different scales. We suppose
that the additional moduli (shooting-star moduli) is responsible for the
curvature perturbation at the earlier inflationary epoch and it generates the
fluctuation with n>1 spectral index at this scale. After a while, another
moduli (or inflaton) takes the place and generates the perturbation with n<1.
At the transition point the two fluctuations are comparable with each other. We
show how the spectral index is affected by the transition induced by the
shooting-star moduli.Comment: 14 pages, latex, accepted for publication in JHE
Non-Gaussian isocurvature perturbations in dark radiation
We study non-Gaussian properties of the isocurvature perturbations in the
dark radiation, which consists of the active neutrinos and extra light species,
if exist. We first derive expressions for the bispectra of primordial
perturbations which are mixtures of curvature and dark radiation isocurvature
perturbations. We also discuss CMB bispectra produced in our model and forecast
CMB constraints on the nonlinearity parameters based on the Fisher matrix
analysis. Some concrete particle physics motivated models are presented in
which large isocurvature perturbations in extra light species and/or the
neutrino density isocurvature perturbations as well as their non-Gaussianities
may be generated. Thus detections of non-Gaussianity in the dark radiation
isocurvature perturbation will give us an opportunity to identify the origin of
extra light species and lepton asymmetry.Comment: 32 pages, 7 figure
On-farm diversity assessment and evaluation of finger millet genotypes in the mid-hills of Nepal
The objective of the study is to assess the phenotypic diversity among the finger millet genotypes and evaluate overall performance for the recommendation of genotypes to the farming community of mid hills of Nepal. The overall performance of 8 candidate genotypes selected from diversity block of 46 varieties in 2015, were assessed in randomized complete block design (RCBD) with three replicates under on-farm conditions in Lamjung district during 2016. Highly significant (p≤0.01) variability among the selected 8 genotypes for agro-morphological traits viz., plant height, number of fingers per head, grain yield, 1000 grain weight, straw yield, days to heading and maturity was revealed. Strong inter-correlation among grain yield, plant height, time to flowering and straw yield was detected. The traits viz., plant height, grain yield, straw yield, days to heading and days to maturity were the most important traits contributing to the overall variability and thus, provide options for selection
Synthesis, Characterization and Antimicrobial Screening of Novel Hydrazide Ligand & It’s Transition Metal Complexes
Published ArticleDifferent transition metal complexes were synthesized from novel 3-bromo-2-[1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-
yl)ethylidene]hydrazide ligand (H2L) and characterized by spectral techniques. The synthesized ligand was found to act mono as well as
di deprotonated (OH, NH) manner and stoichiometry of the ligand to metal ions was confirmed to be 1:1 in case of complex using metal
chloride salts, whereas 1:2 in case of metal(II) complexes using metal acetate(II) salt. Structures of metal complexes were confirmed by
IR, 1H NMR, TGA, XRD, elemental analysis and UV technique which revealed that Mn(II), Co(II), Ni(II), Cu(II) complexes were
octahedral geometry and those of Cu(II), Zn(II) showed square planner and tetrahedral geometry around metal ion respectively. Furthermore
H2L and its metal complexes were screened for antimicrobial activity which showed that ligand enhanced its biological activity after
coordination with metal ions. In particular, Cd(II) and Mn(II) complexes exhibited excellent antifungal activity
Bianchi Type III Anisotropic Dark Energy Models with Constant Deceleration Parameter
The Bianchi type III dark energy models with constant deceleration parameter
are investigated. The equation of state parameter is found to be time
dependent and its existing range for this model is consistent with the recent
observations of SN Ia data, SN Ia data (with CMBR anisotropy) and galaxy
clustering statistics. The physical aspect of the dark energy models are
discussed.Comment: 12 pages, 2 figures, Accepted version of IJT
Constraining Scale-Dependent Non-Gaussianity with Future Large-Scale Structure and the CMB
We forecast combined future constraints from the cosmic microwave background
and large-scale structure on the models of primordial non-Gaussianity. We study
the generalized local model of non-Gaussianity, where the parameter f_NL is
promoted to a function of scale, and present the principal component analysis
applicable to an arbitrary form of f_NL(k). We emphasize the complementarity
between the CMB and LSS by using Planck, DES and BigBOSS surveys as examples,
forecast constraints on the power-law f_NL(k) model, and introduce the figure
of merit for measurements of scale-dependent non-Gaussianity.Comment: 28 pages, 8 figures, 2 tables; v2: references update
The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour
Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect
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