What are the available datatypes for 'dtype' with NumPy's loadtxt() an genfromtxt?

Question

What are the available numpy.loadtxt or numpy.genfromtxt for importing table data with varying datatypes, and what are the available abbreviations for the use (e.g.

Answer 1

for k, v in np.sctypeDict.iteritems(): print '{0:14s} : {1:40s}'.format(str(k), v)

Q              :       
U              : 
a              : 

etc.