Base excess in the other. A secondary (compensatory) process can be readily identified because it "opposes" the observed deviation in blood pH. For example, inadequate ventilation, a respiratory problem, causes a buildup of CO, hence respiratory acidosis; the kidneys then attempt to compensate for the low pH by raising blood bicarbonate. The kidneys only partially compensate, so the patient may still have a low blood pH, i.e. acidosis. In summary, the kidneys partially compensate for respiratory acidosis by raising blood bicarbonate. A high base excess, thus metabolic alkalosis, usually involves an excess of bicarbonate. It can be caused by A base deficit
Water organ by the Greeks, the hydraulis continued to be used through antiquity in the Roman world. In the Middle Ages, Eastern Roman (Byzantine) and Muslim inventors developed, among other pieces, an automatic hydraulic organ (described by the Banu Musa in their 9th-century treatise "Book of Ingenious Devices"), a 'musical tree' at the palace of Khalif al-Muqtadir (ruled 908–32), and a long-distance hydraulic organ that could be heard from sixty miles away (described in the Arabic "Sirr al-asrar" and later translated into Latin by Roger Bacon). By the end of the 13th century hydraulic automata had reached Italy and the rest of