La ciencia

A virtual world is an online community that often takes the form of a computer-based simulated environment through which users can interact with one another and use and create objects.[1] The term has become largely synonymous with interactive 3D virtual environments, where the users take the form of avatars visible to others.[2] These avatars usually appear as textual, two-dimensional, orthree-dimensional representations, although other forms are possible (auditory and touch sensations for example).[3][4] Some, but not all, virtual worlds allow for multiple users.
The computer accesses a computer-simulated world and presents perceptual stimuli to the user, who in turn can manipulate elements of the modeled world and thus experience a degree of telepresence.[5] Such modeled worlds andtheir rules may draw from the reality or fantasy worlds. Example rules are gravity, topography, locomotion, real-time actions, and communication. Communication between users can range from text, graphical icons, visual gesture, sound, and rarely, forms using touch, voice command, and balance senses.
Massively multiplayer online games depict a wide range of worlds, including those based on fantasy,science fiction, the real world, super heroes, sports, horror, and historical milieus. The most common form of such games are fantasy worlds, whereas those based on the real world are relatively rare.[6] Many MMORPGs have real-time actions and communication. Players create a character who travels between buildings, towns, and worlds to carry out business or leisure activities. Communication isusually textual, but real-time voice communication is also possible. The form of communication used can substantially affect the experience of players in the game.[7]
Virtual worlds are not limited to games but, depending on the degree of immediacy presented, can encompass computer conferencing and text based chatrooms. Sometimes, emoticons or 'smilies' are available, to show feeling or facialexpression. Emoticons often have a keyboard shortcut.[8] Edward Castronova is an economist who has argued that "synthetic worlds" is a better term for these cyberspaces, but this term has not been widely adopted.

The First 48
The First 48 is an American documentary television series that airs on A&E. Filmed in various cities in the United States, the series offers an insider's look at thereal-life world of homicide investigators. While the cinema-verite series often follows the investigations to their end, it usually focuses on their first 48 hours, hence the title.
While most cases are solved within the first 48 hours, some go on days, weeks, or months after the first 48. The shortest investigation was led by Det. Brenda Wescott, who arrested a suspect, just 6 hours into theinvestigation.
In 2006, the series was nominated for a Distinguished Documentary Achievement Award, in the Continuing Series category, by the International Documentary Association, eventually losing out to American Experience.
Dion Graham is featured as the narrator, and is the only member of the cast to be in every one of the episodes.[1]
On March 3, 2009, it was renewed for its 9th season byA&E, and currently[when?] has 152 episodes.[2] By season 6, The First 48 had become the highest rated non-fiction justice series on American television, and had gained considerable critical acclaim along with controversy.[3] The season 8 premiere on January 1, 2009 garnered a domestic audience of 2.3 million viewers making it the series' most watched episode, thus far.[4]
Each episode picks one ormore homicides in different cities, covering each alternately, showing how detectives use forensic evidence, witness interviews and other advanced detective skills to identify suspects.
The series has aired several follow-up episodes entitled After the First 48, which detail the trials of those accused in previous episodes, and the aftermath of victims' survivors. There is also a new spin-off,...