Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stability and Hopf bifurcation analysis for the
  hypothalamic-pituitary-adrenal axis model with memory   This paper generalizes the existing minimal model of the
hypothalamic-pituitary-adrenal (HPA) axis in a realistic way, by including
memory terms: distributed time delays, on one hand and fractional-order
derivatives, on the other hand. The existence of a unique equilibrium point of
the mathematical models is proved and a local stability analysis is undertaken
for the system with general distributed delays. A thorough bifurcation analysis
for the distributed delay model with several types of delay kernels is
provided. Numerical simulations are carried out for the distributed delays
models and for the fractional-order model with discrete delays, which
substantiate the theoretical findings. It is shown that these models are able
to capture the vital mechanisms of the HPA system.

28
The categories of this paper are: alg-geom
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The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
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The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics