Prayer is an invocation or act that seeks to activate a rapport with a deity, an object of worship, or a spiritual entity through deliberate communication. Prayer can be a form of religious practice, may be either individual or communal and take place in public or in private. It may involve the use of words or song. When language is used, prayer may take the form of a hymn, incantation, formal creed, or a spontaneous utterance in the praying person. There are different forms of prayer such as petitionary prayer, prayers of supplication, thanksgiving, and worship/praise. Prayer may be directed towards a deity, spirit, deceased person, or lofty idea, for the purpose of worshipping, requesting guidance, requesting assistance, confessing sins or to express one's thoughts and emotions. Thus, people pray for many reasons such as personal benefit or for the sake of others. Yoga is also a common form of prayer.
Most major religions involve prayer in one way or another. Some ritualize the act of prayer, requiring a strict sequence of actions or placing a restriction on who is permitted to pray, while others teach that prayer may be practiced spontaneously by anyone at any time.
Scientific studies regarding the use of prayer have mostly concentrated on its effect on the healing of sick or injured people. Meta-studies of the studies in this field have been performed showing evidence only for no effect or a potentially small effect. For instance, a 2006 meta analysis on 14 studies concluded that there is "no discernable effect" while a 2007 systemic review of intercessory prayer reported inconclusive results, noting that 7 of 17 studies had "small, but significant, effect sizes" but the review noted that the most methodologically rigorous studies failed to produce significant findings. The efficacy of petition in prayer for physical healing to a deity has been evaluated in numerous other studies, with contradictory results. There has been some criticism of the way the studies were conducted.
A hand (med./lat.: manus, pl. manūs) is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates and humans, chimpanzees, monkeys, and lemurs. A few other vertebrates such as the koala (which has two opposable thumbs on each "hand" and fingerprints remarkably similar to human fingerprints) are often described as having either "hands" or "paws" on their front limbs.
Hands are the main structures for physically manipulating the environment, used for both gross motor skills (such as grasping a large object) and fine motor skills (such as picking up a small pebble). The fingertips contain some of the densest areas of nerve endings on the body, are the richest source of tactile feedback, and have the greatest positioning capability of the body; thus the sense of touch is intimately associated with hands. Like other paired organs (eyes, feet, legs), each hand is dominantly controlled by the opposing brain hemisphere, so that handedness, or the preferred hand choice for single-handed activities such as writing with a pencil, reflects individual brain functioning.
Some evolutionary anatomists use the term hand to refer to the appendage of digits on the forelimb more generally — for example, in the context of whether the three digits of the bird hand involved the same homologous loss of two digits as in the dinosaur hand.