Credits for pictures

Some of the pictures used in the first, second and fifth chapters have been taken from some on-line resources and published articles. We have not asked for authorization to the authors, as this work is not meant to be published or sold. However we cite here their sources:

• The picture in the title page of Chapter 1 comes from the web site of Bob Behringer
  http://www.phy.duke.edu/~bob/

• Fig. fig_forcechain comes from the web site of Bob Behringer
  http://www.phy.duke.edu/~bob/

• Fig. fig_sound comes from the web site of the Chicago Group
  http://arnold.uchicago.edu/~jaeger/granular2/

• Fig. fig_slow_compaction comes from the article of Knight et al. [126]

• Fig. fig_tetris comes from the web site of Vittorio Loreto
  http://pil.phys.uniroma1.it/~loreto/science2.html

• Fig. fig_sandpile comes from the Nature website
  http://www.nature.com/nature/debates/earthquake/equake_5.html

• Fig. fig_sandpile2 comes from the article of Nagel [169]

• Fig. fig_couette comes from the web site of Bob Behringer
  http://www.phy.duke.edu/~bob/

• Fig. fig_draining comes from the page of Arshad Kudrolli
  http://physics.clarku.edu/~akudrolli/silo.html

• Fig. fig_kudrolli comes from the page of Arshad Kudrolli
  http://physics.clarku.edu/~akudrolli/nls.html

• Fig. fig_coffee comes from the web site of the Chicago Group
  http://arnold.uchicago.edu/~jaeger/granular2/

• Fig. fig_patterns comes from the web site of Paul B. Umbanhowar
  http://www.aps.org/mar96/vpr/Q5.02.html

• Fig. fig_oscillon comes from the web site of Paul B. Umbanhowar
  http://www.aps.org/mar96/vpr/Q5.02.html

• Fig. fig_kadanoff comes from the web site of the Chicago Group
  http://arnold.uchicago.edu/~jaeger/granular2/

• Fig. fig_zhou comes from the web site of the Chicago Group
  http://arnold.uchicago.edu/~jaeger/granular2/

• Fig. fig_disp_rel comes from the article of Orza et al. [176].