
Vasubandhu describes them as able to generate the resolve to cultivate and accumulate the bases for the Arising of the Bodhicitta. You can find out more about them in Sangharakshita's books The Meaning of Conversion in Buddhism and The Bodhisattva Ideal.
Saddhanandi gave this talk on a meditation retreat for women who have asked for ordination. The complete set of talks is as follows and each one finishes with a led reflection on the theme.
Factor 1: Reflecting on the Buddha, by Saddhanandi
Factor 2: Contemplating the Faults of Existence, by Dhammadassin
Factor 3: Contemplating the Suffering of Beings, by Kulaprabha
Factor 4: Contemplating the Qualities of the Tathagathas, by Samantabhadri
Given at Taraloka in February, 2010.