Virtual water. Virtual water trade (also known as trade in embedded or embodied water) refers to the hidden flow of water if food or other commodities are traded from one place to another. For instance, it takes 1,340 cubic meters of water (based on the world average) to produce one metric tonne of wheat.
At the same time, researchers also say poor understanding of truly dangerous spider bites delays treatment when a person really has been bitten by a dangerous spider. For example, the bite of the brown recluse spider can cause death of a sizeable area of skin (skin necrosis) resulting in a deep, scarring ulcer. Yet even in areas infested with brown recluse spiders, true bites are uncommon. The analysis is published in the July 14 online issue of The Lancet.
A primary concern of the bite of a spider is the effect of its venom. A spider envenomation occurs whenever a spider injects venom into the skin. Not all spider bites involve injection of venom, and the amount of venom injected can vary based on the type of spider and the circumstances of the encounter.