Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Signatures of human impact on self-organized vegetation in the Horn of
  Africa
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc