Sector of a circle

Normally, thrombin is present in the blood as an inactive proenzyme (see p. 270). Prothrombin is activated in two different ways, both of which represent cascades of enzymatic reactions in which inactive proenzymes (zymogens, symbol circle) are proteolytically converted into active proteinases (symbol sector of a circle). The proteinases activate the next proenzyme in turn, and so on. Several steps in the cascade require additional protein factors (factors 111, Va and Villa) as well as anionic phospholipids (PL see below) and Ca "" ions. Both pathways are activated by injuries to the vessel wall. 

A sector of a circle is a region contained within the interior of a central angle and arc. 

Kreis-ausschnitt. m. sector, -bahn, /. circular path orbit, -bewegung,/. circular motion, rotation, revolution, -blende, /. (Photog.) iris diaphragm, -bogen, m. arc of a circle circular arch. 

The area of a sector is found in a similar way to finding the length of an arc. To find the area of a sector, simply multiply the area of a circle, nr2, by the fraction 3f 0, again using x as the degree measure of the central angle. Example ... 

To Find the Area of a Segment of a Circle. Find the area of a sector of a curole having the same arc, and deduct the triangle formed between the two radii and the chord of the arc. 

Pie Chart n A type of quantitative graphical display used for displaying and summarizing categorical data in the form of a circle divided by radii into sectors whose included angle represents the proportion of the data in that category. 

Figure 9. Schematic representation of the infused sector of a polymer in which the infusant-modified region is represented by a shaded circle and the pure polymeric region by an open circle.

We must have a way of organizing this disk into usable sections. It s done by first dividing up the platters into sections as you would a pie and then further dividing this area into concentric circles, called tracks (see Figure 4.2). Tracks are numbered from the outside (track 0) to the inside (track 902 on a 903-track hard disk). A disk sector is the part of a track that falls in a particular section of the pie slice on the disk. 

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