All articles starting with O
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Ornithodoros moubata
Ornithodoros moubata, the eyeless tampan (Argas moubata, Murray 1877), is an East and southern African soft tick that rapidly feeds on warthogs and humans, vectors Borrelia duttonii relapsing fever and African swine fever virus, and produces the complement inhibitor OmCI.
Ornithodoros savignyi
Ornithodoros savignyi, the sand tampan, is an eyed African and Asian soft tick (Argasidae) that feeds rapidly on livestock, causes lethal cardiac sand tampan toxicosis via TSGP toxins, and vectors Candidatus Borrelia kalaharica.
Ornithogalum
Ornithogalum is a genus of bulbous flowering plants in the asparagus family, native from Europe to Afghanistan and southern Africa, known in gardens as star of Bethlehem.
Ornithologic zoo
Bainiao Garden (百鸟园), an aviary zoo on Yingxiong Mountain in Qinyuan, Gulangyu, Xiamen; about 7,000 m², over 80–100 bird species and roughly 1,000 birds, with bird shows and feeding displays.
Ornithology
Ornithology, the scientific study of birds, from Aristotle and Ray and Willughby's 1678 Ornithology through Linnaean taxonomy, Audubon, and modern citizen science (eBird) and bird conservation research.
Ornithonyssus
Ornithonyssus is a genus of Macronyssidae blood-feeding mites including the northern fowl mite (O. sylviarum), tropical fowl mite (O. bursa), and tropical rat mite (O. bacoti), permanent ectoparasites of birds and rodents with 5-12 day life cycles.
Ornithonyssus sylviarum
Ornithonyssus sylviarum, the northern fowl mite (Macronyssidae), is a permanent blood-feeding ectoparasite of birds and the main poultry mite pest in North America, completing its 5-12 day life cycle on the host and reducing egg production.
Ornithopter
An ornithopter is an aircraft that generates both lift and thrust by flapping its wings like a bird or insect, spanning rubber-powered toys, micro drones, and research robots.
Ornithopus
Ornithopus (bird's-foot, serradella) is a genus of six annual legume species in Fabaceae, tribe Loteae, native from Macaronesia and Europe to Iran and disjunctly to South America; O. sativus is a widely sown forage legume on acidic sandy soils.
Ornithopus sativus
Ornithopus sativus, known as French serradella or pink serradella, is an annual legume in the pea family, native to southwestern Europe and northwestern Africa and grown as forage.
Ornoi
Ornoi (Ὄρνοι), also Orni, Bornos, or Ornos, a town of ancient Thrace mentioned by Hierocles, tentatively placed south of İnecik in Tekirdağ province, European Turkey, and classified as a lost settlement.
Ornstein–Uhlenbeck operator
The Ornstein–Uhlenbeck operator is the infinitesimal generator of the Ornstein–Uhlenbeck semigroup, acting as Δf − ⟨x, ∇f⟩; it is the Gaussian analog of the Laplacian, named for its 1930 paper.
Ornstein–Uhlenbeck process
The Ornstein–Uhlenbeck process, introduced by Uhlenbeck and Ornstein in 1930, is a mean-reverting stochastic process that is Gaussian, Markovian, and stationary, used to model Brownian-particle velocity and interest rates.
Ornstein–Zernike equation
The Ornstein–Zernike equation, or OZ equation, connects the total and direct correlation functions of a classical fluid through a convolution, introduced in 1914 to describe critical opalescence and scattering.
Orny Adams
Orny Adams (Adam Ornstein), American stand-up comedian and actor born 1970 in Lexington, Massachusetts; co-star of Seinfeld's documentary Comedian, Coach Finstock on Teen Wolf, and host of the podcast What's Wrong with Orny Adams.
Oro (Street Fighter)
Oro is a Street Fighter character, a one-armed hermit first appearing in Street Fighter III: New Generation and returning as Season 5 DLC in Street Fighter V on August 16, 2021, with Double Jump and Tengu Stone moves.
Óró sé do bheatha abhaile
Óró sé do bheatha abhaile ("you are welcome home") is a traditional Irish song, originally a Jacobite welcome for Charles Edward Stuart (1745), rewritten by Pádraig Pearse into a rebel anthem honoring Gráinne Mhaol (Grace O'Malley), used as an Irish Volunteers marching song and recorded widely.
Orobanchaceae
Orobanchaceae (broomrape family), Ventenat 1799, is the largest family of parasitic flowering plants in Lamiales, with over 2,000 species in about 90-115 genera, spanning non-parasitic, hemiparasitic, and holoparasitic members including Striga and Orobanche crop pests.
Orobanche
Orobanche (broomrapes), holoparasitic Orobanchaceae genus published 1753; chlorophyll-free root parasites on Asteraceae and other hosts; 174 species in 2025 broad circumscription; crop pests like O. crenata and O. cumana.
Orochimaru (Naruto)
Orochimaru (大蛇丸) is a Naruto manga and anime villain by Masashi Kishimoto, a rogue Konoha Sannin seeking immortality via Living Corpse Reincarnation, founder of Otogakure, killer of the Third Hokage, later Mitsuki's non-binary parent in Boruto.
Orocos
Orocos (Open RObot COntrol Software) is an open-source C++ project for real-time, component-based robot control software, started in 2001 as an EU-sponsored project; its core is the Real-Time Toolkit.
Orocual Oil Field
Orocual is an oil and gas field in northern Monagas state, eastern Venezuela, about 20 km northwest of Maturín, producing light oil and condensate since its 1933 discovery.
Orodes II
Orodes II (اورود دوم) was king of kings of the Parthian Empire from 58/57 to 37 BCE, best known for the defeat of Crassus at Carrhae in 53 BCE.
Orofacial granulomatosis
Orofacial granulomatosis (OFG, ICD-11 DA01.21) is a rare chronic granulomatous inflammation of lips and mouth with non-caseating granulomas on biopsy, related to Crohn disease, treated with steroids, diet, and biologics.
Orofaciodigital syndrome type 1
Orofaciodigital syndrome type 1 (OFD1, Papillon-Léage-Psaume syndrome) is a rare X-linked dominant ciliopathy caused by OFD1 gene mutations, lethal in most males, causing oral, facial, and digital malformations plus polycystic kidney disease in females.
Orofaciodigital syndrome type 14
Orofaciodigital syndrome type 14 (OFD14, OMIM 615948) is a rare autosomal recessive ciliopathy caused by C2CD3 mutations on 11q13, marked by oral, facial, and digital malformations with severe microcephaly and molar tooth sign.
Orofaciodigital syndrome type 2
Orofaciodigital syndrome type 2 (OFD2, Mohr syndrome, OMIM 252100) is a rare autosomal recessive ciliopathy with cleft lip/palate, tongue nodules, dental agenesis, and poly-syn-brachydactyly; NEK1 variants found in one family.
Orofaciodigital syndrome type 4
Orofaciodigital syndrome type 4 (OFD4), Mohr-Majewski or Baraitser-Burn syndrome, is a rare autosomal recessive ciliopathy caused by TCTN3 variants, marked by postaxial polydactyly, tibial hypoplasia, oral anomalies, and kidney, liver, and brain involvement.
Orofaciodigital syndrome type 5
Orofaciodigital syndrome type 5 (Thurston syndrome, OFD5) is a rare autosomal recessive ciliopathy with postaxial polydactyly, median cleft of the upper lip, and DDX59 mutations on chromosome 1q32.
Orofaciodigital syndrome type 9
Orofaciodigital syndrome type 9 (OFD9, Gurrieri syndrome, OMIM 258865) is a rare autosomal recessive ciliopathy with oral, facial, and digital anomalies plus retinal coloboma; genes TBC1D32 and SCLT1.