FIGURE
3 as boxes. Since we were interested in how the
values of these variables change over time, we defined time as an additional
variable, denoted t.4. Model variables and parameters
In mathematical
modeling terminology, SB, IB, SM,
and IM are known as variables. They represent the
number of individuals in each of those four groups, and are shown in FIGURE
3 as boxes. Since we were interested in how the
values of these variables change over time, we defined time as an additional
variable, denoted t.
The fate of
individuals in each group is described by parameters, which are indicated
in FIGURE 3 by arrows. We estimated the
values of the parameters from published biological literature on birds and
mosquitoes. To focus our model on the New York City outbreak, we used biological data for the hardest-hit bird hosts,
American crows Corvus brachyrhynchos, and the most common mosquito
vectors, Culex pipiens.
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