All articles starting with S
44,216 articles
Sigma Plan
The Sigma Plan (Dutch: Sigmaplan) is a flood protection and nature restoration program of the Flemish government, launched in 1977 after the January 1976 storm surge floods along the tidal Scheldt in Belgium.
Sigma Scorpii
Sigma Scorpii (σ Sco) is a quadruple star system in Scorpius, a close 33-day binary of two B-type stars plus two fainter companions, shining at magnitude +2.8.
Sigma with Armanni Reign
Sigma with Armanni Reign is the touring billing of English drum and bass duo Sigma with Philadelphia MC Armanni Reign, known for the 2014 UK number ones "Nobody to Love" and "Changing".
Sigma-Aldrich
Sigma-Aldrich, also known as MilliporeSigma, was an American research-chemical and laboratory-supplies company formed in 1975 and headquartered in St. Louis, Missouri, acquired by Merck KGaA in 2015 for about $17 billion.
Sigma-delta ADC
The sigma-delta ADC (Σ-Δ ADC, also written delta-sigma ADC) is an analog-to-digital converter that oversamples with a coarse 1-bit quantizer in a feedback loop, achieving high resolution for precision, low-bandwidth measurement.
Sigma-E factor negative regulatory protein RseA
RseA (regulator of sigma E) is the inner membrane anti-sigma factor of Escherichia coli that sequesters sigma-E (RpoE); envelope stress triggers DegS, RseP, and ClpXP proteolysis of RseA, freeing sigma-E to transcribe envelope stress genes.
Sigmar Gabriel
Sigmar Gabriel (born 1959, Goslar) is a German SPD politician: Lower Saxony minister-president 1999–2003, SPD chairman 2009–2017, Vice Chancellor 2013–2018, Foreign Minister 2017–2018, now Atlantik-Brücke chairman and supervisory board member at Deutsche Bank, Siemens Energy, and Rheinmetall.
Sigmaringen enclave
Sigmaringen enclave: the Hitler-created French exile territory at Sigmaringen castle, Germany, housing Pétain, de Brinon's governmental delegation, and about a thousand Vichy collaborators from September 1944 to April 1945.
SigmaSense
SigmaSense is an Austin, Texas-based sensing semiconductor company founded in 2015 by touchscreen veterans, known for software-defined capacitive sensing and later battery and power sensing.
Sigmatek
Sigmatek (SIGMATEK GmbH & Co KG) is an Austrian manufacturer of complete automation systems for industrial machine and plant engineering, founded in 1988 and headquartered in Lamprechtshausen near Salzburg.
Sigmatropic reaction
A sigmatropic reaction, also called a sigmatropic shift, is a pericyclic reaction in which a σ-bonded atom or group migrates across a π electron system, as in the Claisen and Cope rearrangements.
Sigmatropic rearrangement
A sigmatropic rearrangement is a pericyclic reaction in which a sigma bond flanked by pi systems migrates to a new position in a single concerted step governed by orbital symmetry.
SIGMET
SIGMET, or Significant Meteorological Information, is an ICAO-standard aviation weather warning issued by a meteorological watch office for hazards such as volcanic ash and severe turbulence.
Sigmodon
Sigmodon, the cotton rats, is a genus of sigmodontine rodents described in 1825, ranging from the southern United States to northern South America, with about 13–14 species, S-shaped molars, and wide use as laboratory models for viral disease.
Sigmoid colectomy
Sigmoid colectomy is an operation that removes the sigmoid colon to treat diverticulitis, tumors, or volvulus, with laparoscopic resection now preferred in the elective setting.
Sigmoid colon
Sigmoid colon: S-shaped terminal segment of the large intestine, 25-40 cm, joining descending colon to rectum at S3; intraperitoneal via sigmoid mesocolon, supplied by IMA sigmoidal branches, prone to diverticulitis.
Sigmoid function
The sigmoid function, also called the logistic function or squashing function, is an S-shaped curve mapping real numbers into (0, 1), used in logistic regression and neural networks.
Sigmoidoscopes
Sigmoidoscopes, rigid or flexible endoscopes with a light and camera, examine the rectum and sigmoid colon. Flexible versions, introduced by Overholt in 1962, screen for distal colorectal cancer with low complication rates.
Sigmoidoscopy
Sigmoidoscopy (flexible sigmoidoscopy) is endoscopic examination of the rectum and lower colon with a flexible camera tube. Used for symptoms and CRC screening; RCTs show 28% mortality reduction, benefit limited to distal colon; perforation about 1 in 50,000.
Sigmund Fraenkel
Sigmund Fraenkel, also written Siegmund Fränkel, was an Austrian physician, chemist, and pharmacologist who taught medical chemistry at Vienna and wrote Die Arzneimittel-Synthese, first published in 1901.
Sigmund Freud
Sigmund Freud (1856–1939), Austrian neurologist and founder of psychoanalysis; born in Freiberg, Moravia, worked in Vienna, fled the Nazis in 1938, died in London; wrote The Interpretation of Dreams and Studies on Hysteria.
Sigmund Freud Prize
The Sigmund Freud Prize (German: Sigmund-Freud-Preis für wissenschaftliche Prosa) is an annual German award for excellent academic prose, given by the German Academy for Language and Literature since 1964.
Sigmund Strauss
Sigmund Strauss, also spelled Siegmund Strauß, was an Austrian physicist and radio engineer in Vienna, a pioneer of radio engineering who died in New York in 1942.
Sign
A sign is anything that stands for something else to some interpreter, the subject of semiotics. Peirce gave it a triadic structure and Saussure a dyadic one centered on language.
Sign (semiotics)
Sign (semiotics): the basic unit of semiotics, standing for something else. Defined dyadically by Saussure (signifier plus signified) and triadically by Peirce (representamen, object, interpretant), with icon, index, and symbol as Peirce's principal classes.
Sign Crushes Motorist
sign crushes motorist is the lo-fi slowcore project of Irish musician Liam McCay (born 2005), named after a Duster song. Albums i'll be okay (2022) and Hurting (2023) went viral on TikTok, reaching 2.7 million Spotify monthly listeners.
Sign function
The sign function, also called the signum function and written sgn x, is the function that equals 1, 0, or −1 according to whether x is positive, zero, or negative.
Sign language
Sign language, also called signed languages or pasimology, is a natural language expressed through the hands, face, and body, with more than 300 distinct languages worldwide.
Sign language interpreting
Sign language interpreting is the real-time transfer of meaning between a signed language, such as American Sign Language, and a spoken or written language, crossing sensory modalities.
Sign language recognition
Sign language recognition (SLR) is the automatic identification of sign language content from video or sensor data by a computer, spanning more than 300 distinct sign languages.