Variable in a subroutine - definition

[polak7]

I have a question related to the UEXPAN subroutine. The example from Abaqus Verification Manual is given below:

c
c user subroutine uexpan

      subroutine uexpan(expan,dexpandt,temp,time,dtime,predef,dpred,
     $     statev,cmname,nstatv,noel)
c
      include 'aba_param.inc'
c
      character*80 cmname
c
      dimension expan(*),dexpandt(*),temp(2),time(2),predef(*),
     $     dpred(*),statev(nstatv)
c
	alpha = 1.0d-05
c
	expan(1) = alpha*temp(2)
c
      return
      end

I do not understand this line:

alpha = 1.0d-05

Why the variable "alpha" is not defined in the subroutine? I know that the type of a variable is implied by the first letter of the variable name to be integer or real. But the value of "alpha" equals 1.0d-05, the letter "d" means that the double precision definition is used.
How can it be explained?