Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Linear response of vibrated granular systems to sudden changes in the
  vibration intensity   The short-term memory effects recently observed in vibration-induced
compaction of granular materials are studied. It is shown that they can be
explained by means of quite plausible hypothesis about the mesoscopic
description of the evolution of the system. The existence of a critical time
separating regimes of ``anomalous'' and ``normal'' responses is predicted. A
simple model fitting into the general framework is analyzed in the detail. The
relationship between this work and previous studies is discussed.

17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an