2,996 research outputs found
Effect of X-rays on the somatic chromosomes of the exotic fish, Tilapia mossambica
Male and female T. mossambica were x-rayed with 100 r and the meta-phase chromosome aberrations in their gill epithelia were studied at 13 different intervals against suitable control. The chromosomes of males appeared more radiosensitive than those of females. Among the diploid complement of 44 chromosomes, the individual type aberrations were non-random in both sexes. The longest pair of chromosomes, taken as the marker pair, was found very highly radio-sensitive, while the remaining 21 pairs as non-markers were somewhat resistant to x-radiation when the observed and the expected numbers were subjected to statistical analysis. The break in the marker chromosome was also non-randomly distributed as the distal half had a significantly large number of breaks
Clustering properties of a generalised critical Euclidean network
Many real-world networks exhibit scale-free feature, have a small diameter
and a high clustering tendency. We have studied the properties of a growing
network, which has all these features, in which an incoming node is connected
to its th predecessor of degree with a link of length using a
probability proportional to . For , the
network is scale free at with the degree distribution and as in the Barab\'asi-Albert model (). We find a phase boundary in the plane along which
the network is scale-free. Interestingly, we find scale-free behaviour even for
for where the existence of a new universality class
is indicated from the behaviour of the degree distribution and the clustering
coefficients. The network has a small diameter in the entire scale-free region.
The clustering coefficients emulate the behaviour of most real networks for
increasing negative values of on the phase boundary.Comment: 4 pages REVTEX, 4 figure
Fishery Technology
Not AvailableA unique hook and line technique termed as ?Tuka-feka? to catch Indian Major Carps in Buxar stretch of River Ganga was described in this pape
Order Parameter and Scaling Fields in Self-Organized Criticality
We present a unified dynamical mean-field theory for stochastic
self-organized critical models. We use a single site approximation and we
include the details of different models by using effective parameters and
constraints. We identify the order parameter and the relevant scaling fields in
order to describe the critical behavior in terms of usual concepts of non
equilibrium lattice models with steady-states. We point out the inconsistencies
of previous mean-field approaches, which lead to different predictions.
Numerical simulations confirm the validity of our results beyond mean-field
theory.Comment: 4 RevTex pages and 2 postscript figure
Scaling behavior of the absorbing phase transition in a conserved lattice gas around the upper critical dimension
We analyse numerically the critical behavior of a conserved lattice gas which
was recently introduced as an example of the new universality class of
absorbing phase transitions with a conserved field [Phys. Rev. Lett. 85, 1803
(2000)]. We determine the critical exponent of the order parameter as well as
the critical exponent of the order parameter fluctuations in D=2,3,4,5
dimensions. A comparison of our results and those obtained from a mean-field
approach and a field theory suggests that the upper critical dimension of the
absorbing phase transition is four.Comment: 5 pages, 11 figure
First record of Trachicephalus uranoscopus (Bloch and Schneider, 1801) from Chilika lagoon, Odisha coast of India
1335-1337The present study deals with the first record of Trachicephalus uranoscopus and its morphological descriptions from Chilika lagoon, Odisha coast of India. The species (T. uranoscopus) as well as the family (Synanceiidae) are new additions to the ichthyofaunal diversity of the lagoon
Generic Sandpile Models Have Directed Percolation Exponents
We study sandpile models with stochastic toppling rules and having sticky
grains so that with a non-zero probability no toppling occurs, even if the
local height of pile exceeds the threshold value. Dissipation is introduced by
adding a small probability of particle loss at each toppling. Generically, for
models with a preferred direction, the avalanche exponents are those of
critical directed percolation clusters. For undirected models, avalanche
exponents are those of directed percolation clusters in one higher dimension.Comment: 4 pages, 4 figures, minor change
Path-integral representation for a stochastic sandpile
We introduce an operator description for a stochastic sandpile model with a
conserved particle density, and develop a path-integral representation for its
evolution. The resulting (exact) expression for the effective action highlights
certain interesting features of the model, for example, that it is nominally
massless, and that the dynamics is via cooperative diffusion. Using the
path-integral formalism, we construct a diagrammatic perturbation theory,
yielding a series expansion for the activity density in powers of the time.Comment: 22 pages, 6 figure
The collapsed tetragonal phase as a strongly covalent and fully nonmagnetic state: persistent magnetism with interlayer As-As bond formation in Rh-doped CaSrFeAs
A well-known feature of CaFeAs-based superconductors is the
pressure-induced collapsed tetragonal phase that is commonly ascribed to the
formation of an interlayer As-As bond. Using detailed X-ray scattering and
spectroscopy, we find that Rh-doped CaSrFeAs does
not undergo a first-order phase transition and that local Fe moments persist
despite the formation of interlayer As-As bonds. Our density functional theory
calculations reveal that the Fe-As bond geometry is critical for stabilizing
magnetism and that the pressure-induced drop in the lattice parameter
observed in pure CaFeAs is mostly due to a constriction within the
FeAs planes. These phenomena are best understood using an often overlooked
explanation for the equilibrium Fe-As bond geometry, which is set by a
competition between covalent bonding and exchange splitting between strongly
hybridized Fe and As states. In this framework, the collapsed
tetragonal phase emerges when covalent bonding completely wins out over
exchange splitting. Thus the collapsed tetragonal phase is properly understood
as a strong, covalent phase that is fully nonmagnetic with the As-As bond
forming as a byproduct.Comment: 6 pages, 2 figures, and 1 table. Supplemental materials are available
by reques
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