All articles starting with R
22,461 articles
R1-Zero-style pure RL training
R1-Zero-style pure RL training is a post-training method introduced by DeepSeek-AI in January 2025 with DeepSeek-R1-Zero, showing that reasoning can emerge from rule-based rewards without supervised fine-tuning.
R101
R101 was a British rigid airship built in 1929 that crashed in France on 5 October 1930 on its maiden flight to India, killing 48 of 54 aboard.
R12 cemetery
R12 cemetery is a Neolithic burial site on a natural hill near Kawa in Sudan, excavated from 2000 by Sandro Salvatori and Donatella Usai, dating to about 4780 BC.
R136
R136 is the dense young star cluster at the core of the Tarantula Nebula in the Large Magellanic Cloud, home to several of the most massive stars known.
R136a1
R136a1 is a Wolf–Rayet star at the center of the R136 cluster in the Tarantula Nebula, the most massive star currently known at roughly 170 to 230 solar masses.
R160 (New York City Subway car)
The R160 is a class of New York City Subway cars built by Alstom and Kawasaki between 2005 and 2010 for the B Division lettered lines.
R179 (New York City Subway car)
The R179 is a class of 318 New York City Subway cars built by Bombardier for the B Division, serving the A, C, J, and Z lines.
R18 (British Board of Film Classification)
R18 is the BBFC's legally restricted adult category, created in 1982, for explicit consenting-sex and strong fetish works; films may show only in licensed cinemas, videos sell only in licensed sex shops, no mail order.
R1SE
R1SE (Chinese limited boy group) formed June 8, 2019 on Tencent Video's Produce Camp 2019 with 11 members led by Zhou Zhennan; four albums, 53 songs, disbanded at farewell concert June 13, 2021.
R2-D2
R2-D2, the astromech droid of the Star Wars saga, served Padmé Amidala, Anakin Skywalker, and Luke Skywalker; named from Reel 2, Dialog 2; voiced by Ben Burtt.
R21/Matrix-M malaria vaccine
R21/Matrix-M (CYVAC) is a WHO-recommended, prequalified malaria vaccine for children, developed by Oxford's Jenner Institute with Novavax's Matrix-M adjuvant and made by Serum Institute of India; phase 3 efficacy 75% in seasonal settings, priced under $4 per dose.
R211 (New York City Subway car)
The R211 is a New York City Subway car class built by Kawasaki, ordered in 2018, with wider doors and open gangways, entering service in 2023.
R268 (New York City Subway car)
The R268 is a planned class of 378 New York City Subway cars ordered from Kawasaki in 2025, replacing the R68 and R68A fleets on the lettered lines.
R2Bees
R2Bees, short for Refuse 2 Be Broke, is a Ghanaian hiplife and Afrobeats duo from Tema formed in 2007 by cousins Paedae and Mugeez, winners of six 2013 Ghana Music Awards.
R2D2 (reinforcement learning)
R2D2 (Recurrent Replay Distributed DQN) is a distributed deep reinforcement learning agent introduced at DeepMind in 2019, which trains recurrent-network agents from distributed prioritized experience replay.
r²SCAN
r²SCAN (regularized–restored strongly constrained and appropriately normed) is a meta-GGA exchange-correlation functional for density functional theory, introduced in 2020 to fix SCAN's numerical instabilities while keeping its accuracy.
r²SCAN-3c
r²SCAN-3c is a composite density-functional theory method for electronic-structure calculations, introduced in 2021 by Stefan Grimme and co-workers at the University of Bonn, combining the r²SCAN functional with dispersion and basis-set corrections.
R3B
R3B (Reactions with Relativistic Radioactive Beams) is an international nuclear physics experiment at FAIR in Darmstadt, Germany, performing kinematically complete studies of exotic nuclei with radioactive beams.
R3hab
R3hab, the stage name of Fadil El Ghoul, is a Dutch-Moroccan DJ and record producer born in Breda in 1986, prominent in Dutch house and known for remixing pop artists.
R3LL
R3LL is the stage name of Terrell Griffith, an American Jersey club producer and DJ from Newark, New Jersey, and an original member of the Brick Bandits crew.
R4 cartridge
R4 cartridge (R4 Revolution for DS), a Slot-1 Nintendo DS flashcart released early 2007 that boots ROMs and homebrew from microSD; limited to 2 GB cards, DS/DS Lite only, widely cloned under the R4 name.
R5 (band)
R5 was an American pop rock band formed in Los Angeles in 2009 by the four Lynch siblings (Ross, Riker, Rocky, Rydel) and drummer Ellington Ratliff, the name referencing their five R-initial names. They released Louder (2013, Billboard 200 No. 24) and Sometime Last Night (2015, No. 6) before becoming The Driver Era in 2018.
R504 Kolyma Highway (Федеральная автомобильная дорога «Колыма»)
The R504 Kolyma Highway, or Road of Bones, is a federal highway in the Russian Far East linking Yakutsk and Magadan, built largely by Gulag prisoners.
R550 Magic
The R550 Magic (Matra R.550) is a French short-range, infrared-homing air-to-air missile developed by Matra from 1968 as an indigenous competitor to the AIM-9 Sidewinder.
R62 (New York City Subway car)
The R62 is a class of 325 New York City Subway cars built by Kawasaki of Japan, delivered from 1983 to 1985 and serving the A Division.
R7 photoreceptor cell
R7 photoreceptor cell (R7 cell, CL:0000707) is the distal inner photoreceptor of each Drosophila ommatidium, UV-sensitive via Rh3 or Rh4, specified by Sevenless/Boss and Notch signaling, projecting to medulla layer M6 for color vision.
Ra
Ra (Re), ancient Egypt's sun god and principal creator deity, whose cult centered on Heliopolis; merged as Ra-Horakhty, Amun-Ra, Atum; attested in Pyramid Texts c. 2400-2300 BCE; honored with 5th Dynasty sun temples.
Ra Capital Nexus
Ra Capital Nexus is a family of healthcare venture capital funds managed by Boston firm RA Capital Management, launched in 2019 and led by Peter Kolchinsky and Rajeev Shah.
Ra Capital Planetary Health
RA Capital Planetary Health is the planetary-health venture capital franchise of Boston-based RA Capital Management, led by Brigid O'Brien and Kyle Teamey, which closed a $120 million fund in 2025.
Ra Kuti
Kuti, or Ra Kuti, was a high Majapahit official who led a 1319 rebellion against King Jayanagara, seizing the capital before Gajah Mada crushed it.