Gamma - Ghb Drug

Gamma (uppercase Î", lowercase γ; Greek: Î"άμμα Gámma) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, gamma represented a voiced velar stop /É¡/. In Modern Greek, it represents a voiced fricative.

Based on its phonetic value in Modern Greek, gamma has also been introduced in a number of modern Latin-alphabet based phonetic notations (Latin (or latinized) gamma Æ").

History

The Greek letter Gamma Î" was derived from the Phoenician letter for the /g/ phoneme (𐤂 gÄ«ml), and as such is cognate with Hebrew gimel ×'. Based on its name, the letter has been interpreted as an abstract representation of a camel's neck, but this has been criticized as contrived, and it is more likely that the letter is derived from an Egyptian hieroglyph representing a club or throwing stick.

In the archaic period, the shape of gamma was closer to a classical lambda (Λ), while lambda retained the Phoenician L-shape (𐌋).

Letters that arose from the Greek gamma include Etruscan (Old Italic) 𐌂, Roman C and G, Runic kaunan áš², Gothic geuua 𐌲, the Coptic Ⲅ, and the Cyrillic letters Ð" and Ґ.

Greek phoneme

The Ancient Greek /g/ phoneme was the voiced velar stop, continuing the PIE voiced velar and palatal stops *g, *ǵ.

The modern Greek phoneme represented by gamma is realized either as a palatal /ʝ/ (before a front vowel, /e, i/), or as a voiced velar fricative /ɣ/ (in all other environments). Both in Ancient and in Modern Greek, before other velars (κ, χ, ξ k, kh, ks), gamma represents a velar nasal /ŋ/. A double gamma γγ represents the sequence /ŋɡ/ (phonetically varying [ŋɡ~ɡ]) or /ŋɣ/.

Phonetic transcription

Lowercase Greek gamma is used in the Americanist phonetic notation and Uralic Phonetic Alphabet to indicate voiced consonants. In International Phonetic Alphabet, it represents the voiced velar fricative.

In these contexts, gamma is considered as an addition to Latin alphabet, the so-called Latin or latinized gamma É£ (with an upper-case variant Æ" based on the minuscule).

Latin gamma is used to represent a voiced velar fricative, both in the International Phonetic Alphabet, and in the alphabets of African languages such as Dagbani, Dinka, Kabiyé, and Ewe, some Berber languages using the Berber Latin alphabet, and sometimes in the romanization of Pashto.

Lowercase Latin gamma is used in the International Phonetic Alphabet to represent the voiced velar fricative. A lowercase Latin gamma that lies above the baseline rather than crossing it (ɤ) represents the close-mid back unrounded vowel. In certain nonstandard variations of the IPA the uppercase form is used.

Mathematics and science

Lower case

The lower-case letter ${\displaystyle \gamma }$ is used as a symbol for:

• Chromatic number of in graph theory
• Gamma radiation in nuclear physics
• The photon, the elementary particle of light and other electromagnetic radiation
• Surface energy in materials science
• The Lorentz factor in the theory of relativity
• In mathematics, the lower incomplete gamma function
• The heat capacity ratio Cp/Cv in thermodynamics
• The activity coefficient in thermodynamics
• The gyromagnetic ratio in electromagnetism
• Gamma waves in neuroscience
• Gamma motor neurons in neuroscience
• A non-SI metric unit of measure of mass equal to one microgram (1 μg). This always-rare use is currently deprecated.
• A non-SI unit of measure of magnetic flux density, sometimes used in geophysics, equal to 1 nanotesla (nT).
• The power by which the luminance of an image is increased in gamma correction
• The Eulerâ€"Mascheroni constant
• In mechanical engineering:
  • Specific weight
  • The shear rate of a fluid is represented by a lower case gamma with a dot above it: ${\displaystyle {\dot {\gamma }}}$
  • Austenite (also known as γ-iron), a metallic non-magnetic allotrope or solid solution of iron.
• The gamma carbon, the third carbon attached to a functional group in organic chemistry and biochemistry; see Alpha and beta carbon

The lowercase Latin gamma ɣ can also be used in contexts (such as chemical or molecule nomenclature) where gamma must not be confused with the letter y, which can occur in some computer typefaces.

Upper case

The upper-case letter ${\displaystyle \Gamma }$ is used as a symbol for:

• In mathematics, the gamma function (usually written as ${\displaystyle \Gamma }$-function) is an extension of the factorial to complex numbers
• In mathematics, the upper incomplete gamma function
• The Christoffel symbols in differential geometry
• In probability theory and statistics, the gamma distribution is a two-parameter family of continuous probability distributions.
• Circulation in fluid mechanics
• As reflection coefficient in physics and electrical engineering
• The tape alphabet of a Turing machine
• The Fefermanâ€"Schütte ordinal ${\displaystyle \Gamma _{0}}$

Encoding

HTML

The HTML entities for uppercase and lowercase gamma are Γ and γ.

Unicode

• Greek Gamma

• Coptic Gamma

• Latin Gamma / phonetic Gamma

• CJK Square Gamma

• Technical / Mathematical Gamma

These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.