Neuroscience

Had enough water? Brain's thirst centers make a gut check

Water bottles are everywhere these days, along with all kinds of advice about exactly how much water you should be drinking. But how does your brain actually know when you've had enough and can stop feeling thirsty? A new ...

Neuroscience

Dopamine primes the brain for enhanced vigilance

Imagine a herd of deer grazing in the forest. Suddenly, a twig snaps nearby, and they look up from the grass. The thought of food is forgotten, and the animals are primed to respond to any threat that might appear.

Immunology

Immune cells turn back time to achieve memory

Memory T cells earn their name by embodying the memory of the immune system - they help the body remember what infections or vaccines someone has been exposed to. But to become memory T cells, the cells go backwards in time, ...

Neuroscience

Research uncovers the neurons that drive thirst

What makes us thirsty? On some level, the answer is obvious: If we don't drink enough water, our bodies send us unpleasant wake-up calls in the form of dry mouths and an strong urge to consume liquid. The deeper answer, a ...

Medical research

BPA may affect the developing brain by disrupting gene regulation

Environmental exposure to bisphenol A (BPA), a widespread chemical found in plastics and resins, may suppress a gene vital to nerve cell function and to the development of the central nervous system, according to a study ...

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Water

Water is a ubiquitous chemical substance, composed of hydrogen and oxygen, that is essential for the survival of many known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam. Water covers 71% of the Earth's surface. On Earth, it is found mostly in oceans and other large water bodies, with 1.6% of water below ground in aquifers and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Saltwater oceans hold 97% of surface water, glaciers and polar ice caps 2.4%, and other land surface water such as rivers, lakes and ponds 0.6%. A very small amount of the Earth's water is contained within biological bodies and manufactured products. Other water is trapped in ice caps, glaciers, aquifers, or in lakes, sometimes providing fresh water for life on land.

Water moves continually through a cycle of evaporation or transpiration (evapotranspiration), precipitation, and runoff, usually reaching the sea. Winds carry water vapor over land at the same rate as runoff into the sea. Over land, evaporation and transpiration contribute to the precipitation over land.

Clean, fresh drinking water is essential to human and other lifeforms. Access to safe drinking water has improved steadily and substantially over the last decades in almost every part of the world. There is a clear correlation between access to safe water and GDP per capita. However, some observers have estimated that by 2025 more than half of the world population will be facing water-based vulnerability. Water plays an important role in the world economy, as it functions as a solvent for a wide variety of chemical substances and facilitates industrial cooling and transportation. Approximately 70 percent of freshwater is consumed by agriculture.

This text uses material from Wikipedia, licensed under CC BY-SA