A answered. Atrial fibrillation can be caused by a number of different things that predispose the heart to arrhythmias. Most commonly, longstanding high blood pressure is the cause. Other causes include heart disease such as blockage in the coronary vessels or diseases such as pneumonia or COPD.
A board, typically with a hole for the thumb, which an artist can hold while painting and on which colors are mixed. 2. a. The range of colors used in a visual medium, in a picture, or by an artist: a limited palette.
French standard sizes for oil paintings refers to a series of different sized canvases for use by artists. The sizes were fixed in the 19th century. Most artists, not only French, used this standard, as it was and still is supported by the main suppliers of artist materials.