Refers to interior of tubular structures in the body like veins.

Biological Tubes

Understanding 'lumen' may involve medical images, as it's internal.

Not Always Visible

A clear lumen can indicate good health; blockages can signal problems.

Health Indicator

Defines brightness of bulbs or lights, more lumens means brighter.

Light Output

Use lumens to find efficient bulbs; higher lumens with lower wattage is better.

Energy Efficiency

Lumens provide a standard to compare different light sources.

Comparison Baseline

Lumen measures visible light, not all types of electromagnetic radiation.

Visible Light

A lumen rating helps compare the brightness of different light sources.

Source Comparison

Control the mood of photos by adjusting the lumens of the lighting equipment.

Brightness Adjustment

 gets into our intestinal tract. It causes fluid to flow from the cells that line our intestine into the lumen, the internal chamber of our intestine, and then that fluid goes the only way it can, which is out the other end. And it flushes out thousands of different other competitors that would otherwise make life difficult for the Vibrios.

Paul Ewald: Can we...

 cells that line our intestine into the lumen the the internal chamber of our intestine and then that fluid goes on when we can which is out the other end and it flushes out thousands of different other competitors that would otherwise make life difficult for the vibrios so what happens if you've got an

Can we domesticate...

 desert the skies are enormous li lumen aided by stars more stars than you can imagine