All articles starting with S
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Sphagnum sect. Subsecunda
Sphagnum section Subsecunda is a major lineage of peat mosses, about 99 species worldwide, recognized by rows of pores on branch leaves and a preference for mineral-rich fens.
Sphagnum squarrosum
Sphagnum squarrosum (Spiky Bog-moss, Crome Sphagnum), section Squarrosa peat moss with strongly squarrose branch leaves, large terminal bud, thin stem cortex; nutrient-rich fens and wet woods, not a peat-former; circumboreal plus New Zealand and South America.
Sphagnum subsecundum species complex
The Sphagnum subsecundum species complex is a group of morphologically intergrading peat mosses in section Subsecunda, including haploid and allopolyploid diploid species restricted to Europe and eastern North America.
Sphalerite
Sphalerite, also known as zinc blende or blackjack, is a zinc sulfide mineral, (Zn,Fe)S, and the world's principal ore of zinc, named from the Greek for treacherous.
Sphaleron
A sphaleron is a static, unstable saddle-point solution of the electroweak field equations, found by Klinkhamer and Manton in 1984, central to baryon number violation and early-universe baryogenesis.
Sphatika bhasma
Sphatika bhasma, also called Shubhra or Fitkari bhasma, is an Ayurvedic calcined potash alum preparation used for wounds, bleeding, vitiligo, and erysipelas, with small clinical and in vitro antimicrobial studies.
Sphecidae
Sphecidae (thread-waisted wasps, mud daubers, digger wasps), Latreille 1802, a family of solitary apoid wasps provisioning larvae with paralyzed arthropods; sensu lato 13 families, over 10,000 species; sensu stricto about 700 species in three subfamilies.
Sphecius speciosus
Sphecius speciosus, the eastern cicada killer, is a large solitary wasp of the eastern United States that hunts cicadas to provision underground nests; it rarely stings.
Sphecodes
Sphecodes (blood bees), genus of cleptoparasitic bees in Halictidae described by Latreille 1804; females kill host eggs in nests of Lasioglossum, Halictus, Andrena; about 326 species worldwide.
Spheniscus
Spheniscus, the banded penguins, is a genus of four allopatric species (African, Humboldt, Magellanic, Galapagos) breeding on cold currents; the only fossil penguins inside the crown clade Spheniscidae belong to it.
Spheniscus humboldti
Spheniscus humboldti, the Humboldt or Peruvian penguin (pingüino de Humboldt), is a Vulnerable banded penguin of the Humboldt Current off Peru and Chile, eating anchovies and sardines, nesting in guano burrows, and suffering sharp El Niño-driven declines.
sPHENIX
sPHENIX is a collider detector at Brookhaven National Laboratory's Relativistic Heavy Ion Collider, built to study the quark-gluon plasma; it took data from 2023 to 2026.
Sphenoid bone
Sphenoid bone (os sphenoidale): unpaired wedge-shaped midline skull-base bone with body, greater and lesser wings, pterygoid processes; sella turcica, sphenoidal sinus, foramina ovale, rotundum, spinosum, optic canal.
Sphenomorphus
Sphenomorphus (forest skinks), genus named by Fitzinger 1843, type species S. melanopogon; about 145 skink species from Southeast Asia to the Solomon Islands, widely paraphyletic and undergoing generic revision.
Sphenopalatine ganglion block
Sphenopalatine ganglion block is a regional nerve block that delivers local anesthetic near the sphenopalatine ganglion, mainly to abort cluster headache attacks and relieve migraine and facial pain.
Sphere
A sphere, also called a two-sphere, is the set of all points at a fixed distance from a center in 3-dimensional space; the solid it encloses is called a ball.
Sphere (1998 film)
Sphere (1998) is a Barry Levinson science fiction psychological thriller starring Dustin Hoffman, Sharon Stone, and Samuel L. Jackson, adapted from Michael Crichton's 1987 novel about a 300-year-old spacecraft on the Pacific floor; a critical and box office failure.
Sphere (novel)
Sphere is a 1987 science fiction novel by Michael Crichton, published by Knopf, in which scientists investigate a huge, apparently undamaged spacecraft on the Pacific ocean floor.
Sphere (venue)
Sphere, also known as MSG Sphere Las Vegas, is an immersive entertainment venue in Las Vegas opened in 2023; it cost $2.3 billion, the most expensive entertainment venue there.
Sphere decoding
Sphere decoding (SD) is a tree-search algorithm for maximum-likelihood MIMO detection that searches only lattice points inside a hypersphere around the received vector, avoiding exhaustive enumeration.
Sphere Entertainment
Sphere Entertainment Co. is an American live-entertainment and media company, spun off from Madison Square Garden Entertainment in April 2023, that operates the Sphere venue in Las Vegas and the MSG Networks regional sports channels.
Sphere of influence
A sphere of influence is a region where a powerful country dominates weaker states' foreign policies while excluding rival great powers, seen in imperial China after 1870.
Sphere packing
Sphere packing is the mathematical problem of arranging identical non-overlapping balls to maximize the fraction of space covered, known as the density, solved in dimensions 8 and 24 in 2016.
Sphere packing in dimensions 8 and 24
Sphere packing in dimensions 8 and 24 was solved in 2016 by Maryna Viazovska and colleagues, who proved the E₈ and Leech lattices are densest.
Sphere shaping precoding
Sphere shaping precoding is transmit-side signal processing that picks the codeword whose energy lies inside a sphere, pre-canceling interference in multiuser MIMO downlinks and in probabilistic amplitude shaping.
SPHERES
SPHERES is a testbed of three bowling-ball-sized free-flying satellites developed by MIT that has operated inside the International Space Station since 2006, demonstrating formation flying and autonomous docking in microgravity.
SPHEREx
SPHEREx is a NASA astrophysics space telescope launched in March 2025 that is conducting the first all-sky near-infrared spectral survey, imaging the entire sky in 102 infrared colors.
Spherical aberration
Spherical aberration is an optical defect in which light rays passing through different zones of a lens or mirror focus at different points, imaging one object point as a blurred disk.
Spherical cap
A spherical cap, also called a spherical dome, is the portion of a sphere cut off by a plane; when the plane passes through the center it is a hemisphere.
Spherical coordinate system
The spherical coordinate system, also called spherical coordinates, is a three-dimensional coordinate system that locates a point by its distance from an origin and two angles.