This gives insights into the biological mechanisms underlying how these 697 genetic variants affect overall height. These loci do not only determine height, but other features or characteristics. As an example, 4 of the 7 loci identified for intracranial volume had previously been discovered for human height.The effect of environment on height is illustrated by studies performed by anthropologist Barry Bogin and coworkers of Guatemala Mayan children living in the United States. In the early 1970s, when Bogin first visited Guatemala, he observed that Mayan Indian men averaged 157.5 centimetres (5 ft 2 in) in height and the women averaged 142.2 centimetres (4 ft 8 in). Bogin took another series of measurements after the Guatemalan Civil War, during which up to a million Guatemalans fled to the United States. He discovered that Maya refugees, who ranged from six to twelve years old, were significantly taller than their Guatemalan counterparts. By 2000, the American Maya were 10.24 cm (4.03 in) taller than the Guatemalan Maya of the same age, largely due to better nutrition and health care. Bogin also noted that American Maya children had relatively longer legs, averaging 7.02 cm (2.76 in) longer than the Guatemalan Maya (a significantly lower sitting height ratio).The Nilotic peoples of Sudan such as the Shilluk and Dinka have been described as some of the tallest in the world. Dinka Ruweng males investigated by Roberts in 1953–54 were on average 181.3 centimetres (5 ft 11+1⁄2 in) tall, and Shilluk males averaged 182.6 centimetres (6 ft 0 in).
Frequency of application can vary from q1h to q8h, depending on both the severity of the lesion, and the formulation used (ointment vs. drops). Much of the pain associated with corneal ulceration is due to the secondary uveitis and miosis, and effective relief can often be gained with topical atropine(1%), leading to mydriasis. Dosing is generally q4h initially, and then as required to maintain dilation. Mydriasis is also important to avoid some of the complications associated with uveitis, such as synechiae formation and glaucoma. Pain is also associated with inflammatory response occurring in the adjacent sclera and conjunctiva, and systemic analgesia in the form of NSAIDs is usually indicated, for example, flunixin meglumin 1.1 mg/kg, BID. Topical NSAIDs are available (diclofenac, flurbiprofen) and effective, but have been shown to increase corneal healing time. In horses that are difficult to treat, or in cases that require very frequent treatment, then placement of a sub-palpebral lavage system can be very useful. As an adjunct to therapy, physical protection of the eye may be required, in the form of a mask. Some horses will rub their eyes in response to pain, and this can cause further corneal damage. Box rest is also vital, as over-exertion has been linked to intra-ocular haemorrhage and increased severity of uveitis. Success in your therapeutic regime can be judged by a reduction in pain, and a decrease in size of the ulcer. Healing generally occurs rapidly at first, followed by a slowing after 5–7 days.