Empire State Building
The Empire State Building is a 102-story contemporary Art Deco style building in New York City, declared by the American Society of Civil Engineers to be one of the Seven Wonders of the Modern World. Designed by Shreve, Lamb and Harmon, it was finished in 1931. The tower takes its name from the nickname of New York State. Since the September 11th attacks, it is again the tallest building in New York City.
Unlike most of today's high-rise buildings, the Empire State has a classic facade. The building's distinctive art deco spire was originally designed to be a mooring mast and depot for zeppelins. However, after a couple of test attempts with airships, the idea proved to be impractical and dangerous due to the powerful updrafts caused by the size of the building itself, though the T-shaped mooring devices remain in place.
Sunday, January 21, 2007
Monday, January 08, 2007
Climate versus weather
In the most succinct words, weather is the combination of events in the atmosphere and climate is the overall accumulated weather in a certain location.The exact boundaries of what is climate and what weather is are not well defined and depend on the application. For example, in some senses an individual El Niño event could be considered climate; in others, as weather.
When the original conception of climate as a long-term average came to be considered, perhaps towards the end of the 19th century, the idea of climate change was not current, and a 30 year average seemed reasonable. Given the current availability of data on long-term trends in the temperature record, it is harder to give a definition of climate to suit all purposes: over a 30 year period, averages may shift; over a shorter period, the statistics are less stable.
In the most succinct words, weather is the combination of events in the atmosphere and climate is the overall accumulated weather in a certain location.The exact boundaries of what is climate and what weather is are not well defined and depend on the application. For example, in some senses an individual El Niño event could be considered climate; in others, as weather.
When the original conception of climate as a long-term average came to be considered, perhaps towards the end of the 19th century, the idea of climate change was not current, and a 30 year average seemed reasonable. Given the current availability of data on long-term trends in the temperature record, it is harder to give a definition of climate to suit all purposes: over a 30 year period, averages may shift; over a shorter period, the statistics are less stable.
Monday, January 01, 2007
Genetic Engineering
Genetic engineering, genetic modification and gene splicing are terms for the process of manipulating genes, usually outside the organism's normal reproductive process. It involves the isolation, manipulation and reintroduction of DNA into cells or model organisms, usually to express a protein. The aim is to introduce new characteristics or attributes physiologically or physically, such as making a crop resistant to an herbicide, introducing a novel trait, or producing a new protein or enzyme. Examples can include the production of human insulin through the use of modified bacteria, the production of erythropoietin in Chinese Hamster Ovary cells, and the production of new types of experimental mice such as the OncoMouse for research, through genetic redesign.
Since a protein is specified by a segment of DNA called a gene, future versions of that protein can be modified by changing the gene's underlying DNA. One way to do this is to isolate the piece of DNA containing the gene, precisely cut the gene out, and then reintroduce the gene into a different DNA segment. Daniel Nathans and Hamilton Smith received the 1978 Nobel Prize in physiology or medicine for their isolation of restriction endonucleases, which are able to cut DNA at specific sites. Together with ligase, which can join fragments of DNA together, restriction enzymes formed the initial basis of recombinant DNA technology.
Genetic engineering, genetic modification and gene splicing are terms for the process of manipulating genes, usually outside the organism's normal reproductive process. It involves the isolation, manipulation and reintroduction of DNA into cells or model organisms, usually to express a protein. The aim is to introduce new characteristics or attributes physiologically or physically, such as making a crop resistant to an herbicide, introducing a novel trait, or producing a new protein or enzyme. Examples can include the production of human insulin through the use of modified bacteria, the production of erythropoietin in Chinese Hamster Ovary cells, and the production of new types of experimental mice such as the OncoMouse for research, through genetic redesign.
Since a protein is specified by a segment of DNA called a gene, future versions of that protein can be modified by changing the gene's underlying DNA. One way to do this is to isolate the piece of DNA containing the gene, precisely cut the gene out, and then reintroduce the gene into a different DNA segment. Daniel Nathans and Hamilton Smith received the 1978 Nobel Prize in physiology or medicine for their isolation of restriction endonucleases, which are able to cut DNA at specific sites. Together with ligase, which can join fragments of DNA together, restriction enzymes formed the initial basis of recombinant DNA technology.
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