Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On the semi-annual, 27 day, variation in geomagnetic activity, cloud
  cover and surface temperature
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th