Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamics of adaptive immunity against phage in bacterial populations   The CRISPR (clustered regularly interspaced short palindromic repeats)
mechanism allows bacteria to adaptively defend against phages by acquiring
short genomic sequences (spacers) that target specific sequences in the viral
genome. We propose a population dynamical model where immunity can be both
acquired and lost. The model predicts regimes where bacterial and phage
populations can co-exist, others where the populations exhibit damped
oscillations, and still others where one population is driven to extinction.
Our model considers two key parameters: (1) ease of acquisition and (2) spacer
effectiveness in conferring immunity. Analytical calculations and numerical
simulations show that if spacers differ mainly in ease of acquisition, or if
the probability of acquiring them is sufficiently high, bacteria develop a
diverse population of spacers. On the other hand, if spacers differ mainly in
their effectiveness, their final distribution will be highly peaked, akin to a
"winner-take-all" scenario, leading to a specialized spacer distribution.
Bacteria can interpolate between these limiting behaviors by actively tuning
their overall acquisition probability.

16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ