3,477 research outputs found
Modeling highly pathogenic avian influenza transmission in wild birds and poultry in West Bengal, India.
Wild birds are suspected to have played a role in highly pathogenic avian influenza (HPAI) H5N1 outbreaks in West Bengal. Cluster analysis showed that H5N1 was introduced in West Bengal at least 3 times between 2008 and 2010. We simulated the introduction of H5N1 by wild birds and their contact with poultry through a stochastic continuous-time mathematical model. Results showed that reducing contact between wild birds and domestic poultry, and increasing the culling rate of infected domestic poultry communities will reduce the probability of outbreaks. Poultry communities that shared habitat with wild birds or those indistricts with previous outbreaks were more likely to suffer an outbreak. These results indicate that wild birds can introduce HPAI to domestic poultry and that limiting their contact at shared habitats together with swift culling of infected domestic poultry can greatly reduce the likelihood of HPAI outbreaks
2D Lattice Liquid Models
A family of novel models of liquid on a 2D lattice (2D lattice liquid models)
have been proposed as primitive models of soft-material membrane. As a first
step, we have formulated them as single-component, single-layered, classical
particle systems on a two-dimensional surface with no explicit viscosity. Among
the family of the models, we have shown and constructed two stochastic models,
a vicious walk model and a flow model, on an isotropic regular lattice and on
the rectangular honeycomb lattice of various sizes. In both cases, the dynamics
is governed by the nature of the frustration of the particle movements. By
simulations, we have found the approximate functional form of the frustration
probability, and peculiar anomalous diffusions in their time-averaged mean
square displacements in the flow model. The relations to other existing
statistical models and possible extensions of the models are also discussed.Comment: REVTeX4, 14 pages in double colomn, 12 figures; added references with
some comments, typos fixe
Coherent bremsstrahlung and GDR width from 252Cf cold fission
The energy spectrum of the high energy gamma-rays in coincidence with the
prompt gamma rays has been measured for the spontaneous fission of 252Cf. The
nucleus-nucleus coherent bremsstrahlung of the accelerating fission fragments
is observed and the result has been substantiated with a theoretical
calculation based on the coulomb acceleration model. The width of the giant
dipole resonance (GDR) decay from the excited fission fragments has been
extracted for the first time and compared with the thermal shape fluctuation
model (TSFM) in the liquid drop formalism. The extracted GDR width is
significantly smaller than the predictions of TSFM.Comment: 12 pages, 3 figures, accepted for publication in Phys. Lett.
Spreading and shortest paths in systems with sparse long-range connections
Spreading according to simple rules (e.g. of fire or diseases), and
shortest-path distances are studied on d-dimensional systems with a small
density p per site of long-range connections (``Small-World'' lattices). The
volume V(t) covered by the spreading quantity on an infinite system is exactly
calculated in all dimensions. We find that V(t) grows initially as t^d/d for
t>t^*$,
generalizing a previous result in one dimension. Using the properties of V(t),
the average shortest-path distance \ell(r) can be calculated as a function of
Euclidean distance r. It is found that
\ell(r) = r for r<r_c=(2p \Gamma_d (d-1)!)^{-1/d} log(2p \Gamma_d L^d), and
\ell(r) = r_c for r>r_c.
The characteristic length r_c, which governs the behavior of shortest-path
lengths, diverges with system size for all p>0. Therefore the mean separation s
\sim p^{-1/d} between shortcut-ends is not a relevant internal length-scale for
shortest-path lengths. We notice however that the globally averaged
shortest-path length, divided by L, is a function of L/s only.Comment: 4 pages, 1 eps fig. Uses psfi
Sexual reproduction of yellow ecotype of Neurospora intermedia in nature
The vegetative stage of yellow ecotype of Neurospora intermedia occurs on various substrates but there has been no evidence of its telomorphic stage in nature. This paper presents evidence for the sexual reproduction of this ecotype in nature on maize cobs
A Super-Fast Distributed Algorithm for Bipartite Metric Facility Location
The \textit{facility location} problem consists of a set of
\textit{facilities} , a set of \textit{clients} , an
\textit{opening cost} associated with each facility , and a
\textit{connection cost} between each facility and client
. The goal is to find a subset of facilities to \textit{open}, and to
connect each client to an open facility, so as to minimize the total facility
opening costs plus connection costs. This paper presents the first
expected-sub-logarithmic-round distributed O(1)-approximation algorithm in the
model for the \textit{metric} facility location problem on
the complete bipartite network with parts and . Our
algorithm has an expected running time of rounds, where . This result can be viewed as a continuation
of our recent work (ICALP 2012) in which we presented the first
sub-logarithmic-round distributed O(1)-approximation algorithm for metric
facility location on a \textit{clique} network. The bipartite setting presents
several new challenges not present in the problem on a clique network. We
present two new techniques to overcome these challenges. (i) In order to deal
with the problem of not being able to choose appropriate probabilities (due to
lack of adequate knowledge), we design an algorithm that performs a random walk
over a probability space and analyze the progress our algorithm makes as the
random walk proceeds. (ii) In order to deal with a problem of quickly
disseminating a collection of messages, possibly containing many duplicates,
over the bipartite network, we design a probabilistic hashing scheme that
delivers all of the messages in expected- rounds.Comment: 22 pages. This is the full version of a paper that appeared in DISC
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