Walter Kaelber, and others, in certain translations of ancient Sanskrit documents Tapas is interpreted as austerities and asceticism; however, this is frequently inadequate because it fails to reflect the context implied, which is of sexual heat or warmth that incubates the birth of life. The idea of linking austerity, exertion, fatigue and self-renunciation to the ancient idea of heat, brooding and inner devotion, comes from the observed labor every mother puts in caring for its embryo and delivering her baby, regardless of the life form. The concept and reference to 'egg hatching' is replaced in Sanskrit texts written in later centuries, with simply 'brooding' or 'incubation'. In ancient literature of Hinduism dedicated to love, desire, lust, seduction and sex, the root of the word Tapas is commonly used. For example, in Atharva Veda, a mantra recommended for a woman who wishes to win or compel a man's love is, 'Love's consuming longing, this passion this yearning, which the gods have poured, into the waters of life, I kindle for thee (tam te tapāmi), by the law of Varuna.' Desire (kāma) is homologized with the concept of Tapas, to explain the feelings and inner energy that leads to sexual intercourse. Agnicayana, Satapatha Brahmana and other ancient texts similarly use the root of the word Tapas to symbolize emotions, biological stages and a mother's effort from conception to the birth of a baby. Both meanings of Tapas are found in various Hindu texts. In some ancient texts, Tapas has the sense of ascetic mortification in a sense similar to other Indian religions, while in the Bhagavad Gita and the Yoga school of Hinduism, the term means self-training and virtuous living in a sense similar to Buddhism. In the Puranas and the texts of the goddess tradition of Hinduism, the term is equivalent to a devotion with intense self-discipline, believed to yield special inner powers. In contemporary usage, any practice that includes hardship and requires perseverance – such as fasting during Vrata – is called Tapas. Yoga and brahmacharya Patañjali, in his Yoga Sūtra, lists Tāpas as one of the Niyamas (virtuous practices), and describes it in several sections such as 2.32, 2.43 and 4.1. The term includes self-discipline, meditation, simple and austere living or any means of inner self-purification. Tapas in the Patanjali text and other Hindu texts on Yoga, states Benjamin Smith, is that which is "a means for perfection of