4,324 research outputs found
A Theoretical Framework for the Analysis of the West Nile Virus Epidemic
We present a model for the growth of West Nile virus in mosquito and bird
populations based on observations of the initial epidemic in the U.S. Increase
of bird mortality as a result of infection, which is a feature of the epidemic,
is found to yield an effect which is observable in principle, viz., periodic
variations in the extent of infection. The vast difference between mosquito and
bird lifespans, another peculiarity of the system, is shown to lead to
interesting consequences regarding delay in the onset of the steady-state
infection. An outline of a framework is provided to treat mosquito diffusion
and bird migration.Comment: 12 pages, 9 postscript figure
Time To Try Mediation Of International Commercial Disputes
How many attorneys in the audience have ever participated in a domestic mediation? I see the hands of about four out of about a hundred people in attendance. How many attorneys in the audience have ever participated in an international mediation? I see two people raising their hands. This is a larger percentage of people than I had anticipated! (laughter
Diffusion and Home Range Parameters from Rodent Population Measurements in Panama
Simple random walk considerations are used to interpret rodent population
data collected in Hantavirus-related investigations in Panama regarding the
short-tailed cane mouse, \emph{Zygodontomys brevicauda}. The diffusion constant
of mice is evaluated to be of the order of (and larger than) 200 meters squared
per day. The investigation also shows that the rodent mean square displacement
saturates in time, indicating the existence of a spatial scale which could, in
principle, be the home range of the rodents. This home range is concluded to be
of the order of 70 meters. Theoretical analysis is provided for interpreting
animal movement data in terms of an interplay of the home ranges, the diffusion
constant, and the size of the grid used to monitor the movement. The study
gives impetus to a substantial modification of existing theory of the spread of
the Hantavirus epidemic which has been based on simple diffusive motion of the
rodents, and additionally emphasizes the importance for developing more
accurate techniques for the measurement of rodent movement.Comment: 18 pages, 5 figure
Diffusion and Home Range Parameters for Rodents: Peromyscus maniculatus in New Mexico
We analyze data from a long term field project in New Mexico, consisting of
repeated sessions of mark-recaptures of Peromyscus maniculatus (Rodentia:
Muridae), the host and reservoir of Sin Nombre Virus (Bunyaviridae:
Hantavirus). The displacements of the recaptured animals provide a means to
study their movement from a statistical point of view. We extract two
parameters from the data with the help of a simple model: the diffusion
constant of the rodents, and the size of their home range. The short time
behavior shows the motion to be approximately diffusive and the diffusion
constant to be 470+/-50m^2/day. The long time behavior provides an estimation
of the diameter of the rodent home ranges, with an average value of 100+/-25m.
As in previous investigations directed at Zygodontomys brevicauda observations
in Panama, we use a box model for home range estimation. We also use a harmonic
model in the present investigation to study the sensitivity of the conclusions
to the model used and find that both models lead to similar estimates.Comment: The published paper in Ecol. Complexity has an old version of Figure
6. Here we have put the correct version of Figure
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