Wednesday, March 26, 2008

A short note on Columbia River

The Columbia River is a river located in British Columbia and the Pacific Northwest of the United States. It is the biggest river in volume flowing into the Pacific Ocean from the North America, and the second biggest in the United States. It is the biggest hydroelectric power producing river in the North America. It starts from its headwaters to the Pacific Ocean it flows 1,270 miles (2,044 km) and it drains 258,000 square miles (415,211 s-kM).
Columbia River is the largest river in the planet that has no delta. The river continues flow west with one small north-northwesterly-directed and stretch near Portland; Vancouver, the Washington; and the confluence with the Willamette River. On this sharp turn the river's flow slows by a long way and it drops the sediment that would generally form a delta.

Wednesday, March 19, 2008

What is cloaking in SEO?

Cloaking is a black hat search engine optimization (SEO) method in which the content offered to the search engine spider is different from that presented to the users' browser. This is completed by delivering content based on the IP addresses or the User-Agent HTTP header of the user demanding the page. When a user is known as a search engine spider, a server-side script delivers a different version of the web page, one that has content not present on the visible page. The use of cloaking is to deceive search engines so they display the page when it would not or else be displayed.

Thursday, March 06, 2008

Formation of a waterfall

Typically, a river flows over a large step in the rocks which may have been formed by a fault line. Over a period of years, the boundaries of this shelf will gradually break away and the waterfall will steadily retreat upstream, creating a gorge of depression. Often, the rock layer just below the more resistant shelf will be of a softer type, meaning undercutting, due to splashback, will occur here to form a thin cave-like formation known as a rock shelter under and behind the waterfall. Finally, the outcropping, more resistant cap rock will fall down under pressure to add blocks of rock to the base of the waterfall. These blocks of rock are then broken down into smaller boulders by attrition as they crash with each other, and they also erode the base of the waterfall by abrasion, creating a deep plunge pool.