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Overview
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File format: VTP - Binary VTK (The Visualization Toolkit) Polydata. 
Method of data collection: These files were generated either through
aDaptive Constrained Constructive Optimization (CCO) or Partitioned aDaptive
Constrained Optimization (PDCCO).
Software: For viewing we should use ParaView. 
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Data variables and units of measurement
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Cell data: cylindrical vascular segment of fixed radius.
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ID_Vessel: Segment ID in the DCCO/PDCCO generation proccess.

beta: Ratio of the segment vessel radius by its parent radius. For the root
vessel we set beta=radius.

branchingType: Determines the branching behaviour of the segment in the
DCCO/PDCCO generation proccess. 0 for non-branching vessels, 1 for fixed vessels,
2 for standard vessels, 3 for distal vessels. 

eqResistance: Reduced hydrodinamic resistance of segment's vascular subtree.
Either in 10^(-2)*Dyn*s*(cm)^-1 or 10^(-3)*Dyn*s*(cm)^-1.

flow: Blood flow through vascular segment. Either in cm^3/s or mm^3/s.

geoConst: length - 2*radius. Either in cm or in mm.

lenght: Length of vascular segment. Either in cm or mm.

level: The level of the segment in the vascular tree structure.

pressure: Static blood pressure in segment. In 10^(-2)*dyn*cm^(-2).

radius: Radius of vascular segment. Either in cm or mm.

resistance: Reduced hydrodinamic resistance of vessel segment. Either in
10^(-2)*Dyn*s*(cm)^-1 or 10^(-3)*Dyn*s*(cm)^-1.

stage: DCCO or PDCCO generation stage.

terminalType: 0 for common, 1 for reserved. Reserved means that the a
predetermined fraction of flow passes through the segment.

vesselFunction: 0 for distribution segment, 1 for perforator segment or 2 for
transport segment. 

viscosity: Dynamic viscosity of blood in this segment. In cP (centiPoise).

strahler (if present): Strahler order of segment.

subtreeVolume (if present): Volume of the subtree starting from this segment.
Either in cm^3 or mm^3.

strahlerConnectivity (if present): Strahler order of segment's parent. For the
root segment we set this value to -1.
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Point data: vertices of each vascular segment.
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flow: Blood flow passing from that point. Either in cm^3/s or mm^3/s.

isDistal: Whether that point is the proximal or distal vertice of the segment.

isTerminal: Whether that point is a leaf node of the vascular tree.

radius: Radius of segment. Either in cm^3/s or mm^3/s.