Geoscience Reference
In-Depth Information
Pigs
Cattle
Iteration infected
N
>40
>10
0-50
51-75
76-90
0 0 0 0
40 km
0
0
91-100
(a)
Latent
Infectious
Recovered
250
350
200
1000
250
150
600
150
100
50
200
50
0
0
0
0
20
40 60
Time step
80
100
0 04060
Time step
80
100
0 04060
Time step
80
100
Recovered
250
350
200
1000
250
150
600
150
100
50
200
50
0
0
0
0 04060
Time step
80
100
0 04060
Time step
80
100
0 04060
Time step
80
100
(b)
FIGURE 6.5 Disease spread modelled using a geographic automata model through a population of cattle
and feral pigs in Texas, United States. Disease was initiated in pigs and allowed to spread through and between
both the pig and cattle populations. The background surfaces are the number of individuals per cell, represent-
ing a herd of animals. The geographic distributions (a) represent the model time step at which each location
became infectious, while the graphs (b) show the epidemic curves (as boxplots) for 100 model repetitions from
the same starting location. (Data from Laffan, S.W. et al., Prev. Vet. Med ., 102, 218, 2011.)
researchers to identify and distinguish between different animals under study, permitting tracking
and behaviour analysis at the level of an individual, instead of studying broader patterns relating
to groups or species (http://www.bto.org/cuckoos). This will empower researchers to ask far more
refined questions about their subjects. Britain, for example, has lost over half of its breeding cuckoos
during the last 25 years. Clearly it is important to understand all aspects of the cuckoo's annual cycle
before one can begin to suggest what might be driving such a decline. The cuckoo has been well
studied during its breeding season in the United Kingdom. Yet once such birds head off on their
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