Renal disease

Your kidneys are two bean-shaped organs, each about the size of your fists. They are located near the middle of your back, just below the rib cage. Inside each kidney about a million tiny structures called nephrons filter blood. They remove waste products and extra water, which become urine. The urine flows through tubes called ureters to your bladder, which stores the urine until you go to the bathroom.

Damage to the nephrons results in kidney disease. This damage may leave kidneys unable to remove wastes. Usually the damage occurs slowly over years. There are no obvious symptoms, so you don't know it is happening.

Many things can cause kidney disease. You are at risk if you have

* Diabetes
* High blood pressure
* A close family member with kidney disease

Virtual private network (VPN)

A virtual private network (VPN) is a computer network in which some of the links between nodes are carried by open connections or virtual circuits in some larger network (e.g., the Internet) instead of by physical wires. The link-layer protocols of the virtual network are said to be tunneled through the larger network when this is the case.

One common application is secure communications through the public Internet, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.

World Wide Web

The World Wide Web (commonly abbreviated as "the Web") is a very large set of interlinked hypertext documents accessed via the Internet. With a Web browser, one can view Web pages that may contain text, images, videos, and other multimedia and navigate between them using hyperlinks. Using concepts from earlier hypertext systems, the World Wide Web was begun in 1992 by the English physicist Sir Tim Berners-Lee, now the Director of the World Wide Web Consortium, and Robert Cailliau, a Belgian computer scientist, while both were working at CERN in Geneva, Switzerland.

In 1990, they proposed building a "web of nodes" storing "hypertext pages" viewed by "browsers" on a network, and released that web in 1992. Connected by the existing Internet, other websites were created, around the world, adding international standards for domain names & the HTML language. Since then, Berners-Lee has played an active role in guiding the development of Web standards (such as the markup languages in which Web pages are composed), and in recent years has advocated his vision of a Semantic Web. Cailliau went on early retirement in January 2005 and left CERN in January 2007.