Many thanks for your replies. It helps. I will try to be more precise later on with an example. I do not forget this thread that I have opened. I will have soon a talk and a paper to publish on the base of this talk, I will goint to start  with an org file.

Sorry for the delay of my reply. 

I like org-mode . ;)

Best wishes,

Jo.  




2014/1/20 Bastien <bzg@altern.org>
Nicolas Goaziou <n.goaziou@gmail.com> writes:

> This is already possible on a case by case basis :
>
>  - @@beamer:<1->@@ Item
>  - @@beamer:<2->@@ ...
>
> and as a frame property:
>
>   * Headline
>     :PROPERTIES:
>     :BEAMER_ACT: [+-]
>     :END:
>
>     - item
>     - item

Great!  Thanks for this :)

--
 Bastien