Even before they are able to talk, infants show remarkable musical abilities that are similar to those of adults in that they are sensitive to musical scales and a regular tempo. Also, infants are able to differentiate between consonant and dissonant intervals. These perceptual skills indicate that music-specific predispositions exist.Prolonged exposure to music develops and refines these skills. Extensive musical training does not seem to be necessary in the processing of chords and keys. The development of musical competence most likely depends on the encoding of pitch along musical scales and maintaining a regular pulse, both of which are key components in the structure of music and aid in perception, memory, and performance. Also, the encoding of pitch and temporal regularity are both likely to be specialized for music processing. Pitch perception is absolutely crucial to processing music. The use of scales and the organization of scale tones around a central tone (called the tonic) assign particular importance to notes in the scale and cause non-scale notes to sound out of place. This enables the listener to ascertain when a wrong note is played. However, in individuals with amusia, this ability is either compromised or lost entirely.Music-specific neural networks exist in the brain for a variety of music-related tasks. It has been shown that Brocas area is involved in the processing of musical syntax.
Melena or melaena refers to the dark black, tarry feces that are associated with upper gastrointestinal bleeding. The black color and characteristic strong odor are caused by hemoglobin in the blood being altered by digestive enzymes and intestinal bacteria.Iron supplements may cause a grayish-black stool that should be distinguished from melena, as should black coloration caused by a number of medications, such as bismuth subsalicylate (the active ingredient in Pepto-Bismol), or by foods such as beetroot, black liquorice, or blueberries. Causes
The most common cause of melena is peptic ulcer disease. However, any bleeding within the upper gastrointestinal tract or the ascending colon can lead to melena. Melena may also be a complication of anticoagulant medications, such as warfarin.Causes of upper gastrointestinal bleeding that may result in melena include malignant tumors affecting the esophagus, stomach or small intestine, hemorrhagic blood diseases, such as thrombocytopenia and hemophilia, gastritis, Stomach cancer, esophageal varices, Meckels diverticulum and Mallory-Weiss syndrome.Causes of "false" melena include iron supplements, Pepto-Bismol, Maalox, and lead, blood swallowed as a result of a nose bleed (epistaxis), and blood ingested as part of the diet, as with consumption of black pudding (blood sausage), or with the traditional African Maasai diet, which includes much blood drained from cattle.Melena is considered a medical emergency as it arises from a significant amount of bleeding. Urgent care is required to rule out serious causes and prevent potentially life-threatening emergencies.A less serious, self-limiting case of melena can occur in newborns two to three days after delivery, due to swallowed maternal blood.