Tuesday, March 25, 2008

Transparent and non-transparent proxy server

The term "transparent proxy" is most often used incorrectly to mean "intercepting proxy" (because the client does not need to configure a proxy and cannot directly detect that its requests are being proxied).

However, RFC 2616 (Hypertext Transfer Protocol -- HTTP/1.1) offers different definitions:

"A 'transparent proxy' is a proxy that does not modify the request or response beyond what is required for proxy authentication and identification".
"A 'non-transparent proxy' is a proxy that modifies the request or response in order to provide some added service to the user agent, such as group annotation services, media type transformation, protocol reduction, or anonymity filtering".

Tuesday, March 18, 2008

SQL/XML, or XML-Related Specifications

The SQL/XML, or XML-Related Specifications, extension to the SQL standard is defined by ISO/IEC 9075-14:2003. SQL/XML specifies SQL-based extensions for using XML in conjunction with SQL. The XML data type is introduced, as well as several routines, functions, and XML-to-SQL data type mappings to support manipulation and storage of XML in a SQL database.

The SQL/XML specification includes functions to construct XML data. These functions allow the user to construct new XML elements or attributes with values e.g. from relational tables. Other functions such as XMLCONCAT or XMLAGG can be used to combine small XML fragments into larger ones. The list of available construction functions includes:

* etc.

Monday, March 10, 2008


Pharmacognosy is the study of medicines derived from natural sources. The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources."

Wednesday, March 05, 2008

Hybrid electric vehicle

A hybrid electric vehicle (HEV) is a vehicle that uses two or more distinct power sources to propel the vehicle. Common power sources include:

• On-board rechargeable energy storage system (RESS) and a fueled power source (internal combustion engine or fuel cell)
• Air and internal combustion engines
• Human powered bicycle with electric motor or gas engine assist
• Human-powered or sail boat with electric power

The term most commonly refers to Hybrid-electric vehicle (HEV) which include internal combustion engines and electric motors.