Purple Membrane fragments in planar Bilayer Lipid Membrane (BLM) can produce different photopotential signals with different ionic strengthes in the media.
The BLM actions are centered on places where long-term overpopulation of the herds " already has stretched the available food and water to its limits" .
Today, the Bureau of Land Management (BLM) and the U.S. Forest Service manage 230 wild-horse territories on about 30 million acres of public lands in 10 states, including Arizona.
Those who advocate for the wild horses say that the BLM action comes from pressure from cattle ranchers, who want to keep the food and water for their livestock.
The BLM alone oversees about 86,000 wild horses- who can live into their 20s-and burros on public lands, more than triple the 27,000 the bureau says the land can sustain.