All articles starting with R
22,461 articles
Rigid image registration
Rigid image registration, also called rigid registration, aligns two views of an object using only translation and rotation, commonly applied to medical scans of the same patient.
Rigid inflatable boat
A rigid inflatable boat (RIB), or rigid-hulled inflatable boat, combines a solid hull with an inflatable collar, giving speed plus buoyancy for rescue, military, and leisure use.
Rigid rotor
The rigid rotor is a model of a rotating molecule whose bond lengths and angles stay fixed, giving rotational energy levels used to read molecular structure from microwave spectra.
Rigid spine syndrome
Rigid spine syndrome, also called rigid spine congenital muscular dystrophy, is a congenital muscular dystrophy described by Victor Dubowitz in 1973, marked by spinal contractures, scoliosis, and progressive respiratory failure.
RIGID-TyG study
RIGID-TyG (NCT07589374), the Cf-PWV and TyG Index Study, is a Brazilian observational cross-sectional study at Hospital de Base, São José do Rio Preto, correlating carotid-femoral pulse wave velocity with the triglyceride-glucose index in 800 adults aged 18–65.
Rigidity matroid
The rigidity matroid of a graph encodes which edge sets are rigid, defined by linear independence in the rigidity matrix; for generic frameworks it depends only on the graph.
Rigo Duterte
Rigo Duterte, born Rodrigo Sangkola Duterte II in 1998, is a Filipino politician and Vice Mayor of Davao City since 2025, grandson of former President Rodrigo Duterte.
Rigobert Song
Rigobert Song Bahanag (born 1976, Nkenglikok) is a Cameroonian former defender and captain, record 137 caps, four World Cups, AFCON winner 2000 and 2002; later Cameroon head coach 2022-2024.
Rigoberta Menchú
Rigoberta Menchú Tum is a K'iche' Maya human rights activist from Guatemala. She won the 1992 Nobel Peace Prize for her work on indigenous rights and social justice.
Rigoberto C. Advíncula
Rigoberto C. Advíncula is a Filipino-American polymer and nanomaterials scientist, UT-ORNL Governor's Chair at Oak Ridge National Laboratory and the University of Tennessee since 2020.
Rigoletto
Rigoletto: Verdi's three-act opera (1851), libretto by Francesco Maria Piave after Victor Hugo's Le roi s'amuse, premiered at La Fenice, Venice; jester Rigoletto, daughter Gilda, Duke of Mantua, "La donna è mobile."
Rigomagus (Germany)
Rigomagus (RIGOMAGVS), Roman auxiliary fort at modern Remagen, Germany; southernmost fort of the Lower Germanic Limes. Founded Augustan era, rebuilt in stone after the Batavian revolt, late Roman fortress, UNESCO World Heritage since 2021.
Rigor mortis
Rigor mortis (dødsstivhet), postmortem muscular stiffening from ATP depletion and persistent actin-myosin binding; begins 1-2 hours after death, follows Nysten's rule, resolves in 24-48 hours.
Rigor Mortis (僵尸) (2013 film)
Rigor Mortis (殭屍, Geung si, 七日重生) is a 2013 Hong Kong horror film, Juno Mak's directorial debut, co-produced by Takashi Shimizu, an homage to the jiangshi genre and Mr. Vampire (1985) starring Chin Siu-ho, Kara Wai, Nina Paw, and Anthony Chan.
Rigorous coupled-wave analysis
Rigorous coupled-wave analysis (RCWA), also known as the Fourier modal method, is a frequency-domain numerical method that solves Maxwell's equations for diffraction by periodic structures such as gratings.
Rigosertib
Rigosertib (ON 01910.Na) is an investigational non-ATP-competitive anticancer drug, a benzyl styryl sulfone sodium salt targeting Plk1, PI3K, and Ras signaling; phase 3 MDS trials (ONTIME) showed no significant survival benefit.
Rigour
Rigour, or rigor, in mathematics is the virtue of a proof that establishes its conclusion through acceptable deductive steps, with no reliance on intuition or unchecked assumptions.
Rigr (crater on Callisto)
Rigr is a 72.5-km-diameter impact crater on Jupiter's moon Callisto at 70.8° N, 244.6° W, approved by the IAU in 1979 and named after a Norse name of the god Heimdall.
Rigshospitalet
Rigshospitalet, Copenhagen University Hospital, Denmark's most specialized hospital, founded 1757 as Det Kongelige Frederiks Hospital by Frederik V, moved to Blegdamsvej in 1910, national referral hospital for Denmark, Greenland, and the Faroe Islands.
Rígsþula
Rígsþula ("The List of Ríg", sometimes "The Lay of Ríg") is an Old Norse eddic-style poem of about 48 stanzas telling how the god Ríg fathered the ancestors of the three social classes and the first king.
Rigveda (ऋग्वेद)
The Rigveda (ऋग्वेद, Rik Veda) is the oldest of the four Vedas of India, a collection of 1,028 Sanskrit hymns praising the Vedic deities, transmitted orally for millennia.
Rihand converter station
The Rihand converter station is the sending-end terminal of the Rihand–Dadri HVDC link, a 1,500 MW system carrying power from Uttar Pradesh toward Delhi since 1990.
Rihand power station
Rihand power station, also known as Rihand Super Thermal Power Station, is a 3,000 MW NTPC coal-fired power station at Rihandnagar in Sonebhadra district, Uttar Pradesh, India.
Rihanna
Rihanna, born Robyn Rihanna Fenty, is a Barbadian singer, songwriter, and entrepreneur who rose to fame in 2005 and became one of the best-selling recording artists in history.
Rihanna albums discography
The albums discography of Barbadian singer Rihanna spans eight studio albums, from Music of the Sun (2005) to ANTI (2016), selling over 45.9 million copies worldwide.
Rihanna singles discography
Rihanna singles discography: 58 singles (13 features, 3 charity) from eight 2005–2016 albums; 14 US and 9 UK number-ones, 200.5 million RIAA single units, first woman past 200 million.
Riheoseol Folk Village
Riheoseol Folk Village (리허설민속촌, Riheoseolminsokchon) is a small theme park and living museum of traditional thatched-roof houses in Geochang-eup, Geochang-gun, South Gyeongsang, South Korea, distinct from Korea's larger national folk villages.
Rihla literature
Rihla literature (Arabic: adab al-riḥla, rihla meaning "voyage") is a classical Arabic prose genre combining travel accounts with commentary on Muslim peoples and practices, whose peak work is Ibn Battuta's rihla of 1354.
Rihla of al-Ghazzal to Spain (1766)
The Rihla of al-Ghazzal to Spain is an Arabic travelogue by the Moroccan scholar and diplomat Ahmad al-Ghazzal about his 1766 embassy to King Carlos III of Spain.
Rihla of Ibn Battuta
The Rihla of Ibn Battuta (تحفة النظار) is an Arabic travel book dictated by Ibn Battuta to the scribe Ibn Juzayy in Fez and completed in 1355–1356.