Thursday, December 31, 2009
Wednesday, December 30, 2009
A spectrogram is an image that shows how the spectral density of a signal varies with time. Also known as spectral waterfalls, sonograms, voiceprints, or voicegrams, spectrograms are used to identify phonetic sounds, to analyse the cries of animals, and in the fields of music, sonar/radar, speech processing, seismology, etc. The instrument that generates a spectrogram is called a spectrograph or sonograph.
Tuesday, December 29, 2009
A spectrograph is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization state.
Sunday, December 27, 2009
Keystroke logging (often called keylogging) is the practice of noting (or logging) the keys struck on a keyboard, typically in a covert manner so that the person using the keyboard is unaware that their actions are being monitored. There are numerous keylogging methods, ranging from hardware- and software-based to electromagnetic and acoustic analysis.
Saturday, December 26, 2009
Astroturfing is a word in American English describing formal political, advertising, or public relations campaigns seeking to create the impression of being spontaneous "grassroots" behavior, hence the reference to the artificial grass, AstroTurf.
The goal of such a campaign is to disguise the efforts of a political or commercial entity as an independent public reaction to some political entity—a politician, political group, product, service or event. Astroturfers attempt to orchestrate the actions of apparently diverse and geographically distributed individuals, by both overt ("outreach", "awareness", etc.) and covert (disinformation) means. Astroturfing may be undertaken by an individual pushing a personal agenda or highly organized professional groups with financial backing from large corporations, non-profits, or activist organizations. Very often the efforts are conducted by political consultants who also specialize in opposition research.
Friday, December 25, 2009
The Mithraic Mysteries or Mysteries of Mithras (also Mithraism) was a mystery religion which became popular among the military in the Roman Empire, from the 1st to 4th centuries AD. It is best attested in the cities of Rome and Ostia and in the Roman provinces of Mauretania, Britain, and in the provinces along the Rhine and Danube frontier.
Christianity was similar to Mithraism in many respects; for instance the Ecclesiastical calendar retains numerous remnants of pre-Christian festivals, notably Christmas, which blends elements including both the feast of the Saturnalia and the birthday of Mithra. Evaluation of the relationship of early Christianity with Mithraism has traditionally been based on the polemical testimonies of the 2nd century Church fathers, such as Justin's accusations that the Mithraists were diabolically imitating the Christians. This led to a picture of rivalry between the two religions, which Ernest Renan set forth in his 1882 The Origins of Christianity by saying "if the growth of Christianity had been arrested by some mortal malady, the world would have been Mithraic," However, Renan's conclusions have been criticised by contemporary scholarship. Edwin M. Yamauchi comments on Renan's work which, "published nearly 150 years ago, has no value as a source. He [Renan] knew very little about Mithraism...” Little was actually known about Mithras in 1882.
Thursday, December 24, 2009
Wednesday, December 23, 2009
Gaffer Gamgee in The Lord of the Rings). The word is probably a shortening of "godfather", with "ga" from association with "grandfather". The female equivalent was "Gammer", which came to colloquially refer to an old lady or gossip.
Tuesday, December 22, 2009
A gaffer in the motion picture industry is the head of the electrical department, responsible for the execution (and sometimes the design) of the lighting plan for a production. The term was also used to describe men who adjusted lighting in English theatre and men who tended street lamps, after the "gaff" they used, a pole with a hook on its end.
Sometimes the gaffer is credited as Chief Lighting Technician (CLT).
Monday, December 21, 2009
Sunday, December 20, 2009
Saturday, December 19, 2009
Friday, December 18, 2009
Thursday, December 17, 2009
Wednesday, December 16, 2009
Botellón is a custom that takes place mainly in the Spanish nightlife, which involves the gathering of a large number of young people mostly between the ages of 16 and 24 outdoors to drink beverages previously acquired in shops (usually supermarkets), to listen to music and talk. This is often done because of the high prices in bars and being underage for bars and clubs.
The word botellón is an augmentative of botella (bottle) so the literal translation would be "big bottle".
Botellón is also used to refer to a drinking pack consisting of an alcoholic drink bottle, soft drink and ice. It is also known as botelleo, botellona, or botelloneo.
Tuesday, December 15, 2009
A stillsuit is a fictional body suit in Frank Herbert's Dune universe, first introduced in the 1965 novel Dune and appearing in every subsequent novel in the series. Stillsuits are worn by the native Fremen of the desert planet Arrakis to maintain their body moisture in the harsh environment. The Science of Dune (2008) analyzes Herbert's stillsuit and its feasibility in the real world as described.
Monday, December 14, 2009
Sunday, December 13, 2009
Saturday, December 12, 2009
Friday, December 11, 2009
Turbodiesel refers to any diesel engine with a turbocharger. Turbocharging is the norm rather than the exception in modern car and truck diesel engines. As with any turbocharged engine, turbodiesels can offer higher specific power outputs, lower emissions levels, improved efficiency and higher refinement levels than their naturally aspirated counterparts.
Thursday, December 10, 2009
Wednesday, December 9, 2009
The following abbreviations are commonly used to describe the length of a DNA/RNA molecule:
Tuesday, December 8, 2009
In mechanical or automotive engineering, a freewheel or overrunning clutch is a device in a transmission that disengages the driveshaft from the driven shaft when the driven shaft rotates faster than the driveshaft. An overdrive is sometimes mistakenly called a freewheel, but is otherwise unrelated.
The condition of a driven shaft spinning faster than its driveshaft exists in most bicycles when the rider holds his or her feet still, no longer pushing the pedals. Without a freewheel the rear wheel would drive the pedals around.
Monday, December 7, 2009
Sunday, December 6, 2009
For example, an article about a country might include a chart or a paragraph describing that country's agricultural exports from a different article about agriculture. Rather than copying the included data and storing it in two places, a transclusion embodies modular design, by allowing it to be stored only once (and perhaps corrected and updated if the link type supported that) and viewed in different contexts. The reference also serves to link both articles.
Saturday, December 5, 2009
Ferrocement has great strength and economy. It is fireproof, earthquake safe and does not rust, rot or blow down in storms. It has a broad range of applications which include home building, creating sculptures, repair of existing artifacts and building boats and ships.
Friday, December 4, 2009
Gondwana (IPA: /ɡɒndˈwɑːnə/), originally Gondwanaland is the name given to a southern precursor-supercontinent (final ongoing joining occurred between ca. 570-510 Ma, joining East Gondwana to West Gondwana) and then as a remnant separated from Laurasia 180- during the breakup of the Pangaea supercontinent that existed about 500 to 200 Ma ago into two large segments. While the corresponding northern hemisphere continent Laurasia moved further north, the nearly equal in area Gondwana included most of the landmasses in today's southern hemisphere, including Antarctica, South America, Africa, Madagascar, Australia-New Guinea, and New Zealand, as well as Arabia and the Indian subcontinent, which have now moved into the Northern Hemisphere. The name is derived from the Gondwana region of central northern India (from Sanskrit gondavana "forest of Gond").
The adjective "Gondwanan" is in common use in biogeography when referring to patterns of distribution of living organisms, typically when the organisms are restricted to two or more of the now-discontinuous regions that were once part of Gondwana; e.g., the Proteaceae, a family of plants that is known only from Chile, South Africa, and Australia are considered to have a "Gondwanan distribution". This pattern is often considered to indicate an archaic, or relict lineage.
Thursday, December 3, 2009
Campanology (from late Latin campana, "bell"; and Greek -λογία, -logia) is the study of bells. It encompasses the physical realities of bells — how they are cast, tuned and sounded — as well as the various methods devised to perform bell-ringing.
It is common to collect together a set of tuned bells and treat the whole as one musical instrument. Such collections — such as a Flemish carillon, a Russian zvon, or a British "ring of bells" used for change ringing — have their own practices and challenges; and campanology is likewise the study of perfecting such instruments, composing music for them, and performing it.
In this sense, however, the word "campanology" is most often used in reference to relatively large bells, often hung in a tower. It is not usually applied to assemblages of smaller bells, such as a glockenspiel, a collection of tubular bells, or an Indonesian gamelan.