All articles starting with R
22,461 articles
Rheometer
A rheometer is a laboratory instrument that measures how materials flow and deform, determining viscosity, yield stress, and viscoelastic properties of fluids and soft solids.
Rheometry
Rheometry, also called shear rheology, is the experimental measurement of how materials flow and deform, quantifying viscosity, viscoelasticity, and yield behavior under applied shear stress or strain.
Rheostatics
Rheostatics, Canadian indie rock band from Etobicoke, Ontario, formed 1978/1980; members Bidini, Tielli, Vesely, Clark, Kerr; known for Whale Music, Melville, the Group of Seven commission, one hit "Claire", 2007 breakup, and 2019 reunion.
Rheotaxis
Rheotaxis is the directed movement of an organism or particle in response to an external fluid flow; in its positive form, the swimmer orients and moves against the current.
Rhesa H. Barksdale
Rhesa H. Barksdale, also known as Rhesa Hawkins Barksdale, is an American jurist serving as a senior judge of the Fifth Circuit Court of Appeals since 2009.
RHESSI
RHESSI (Reuven Ramaty High Energy Solar Spectroscopic Imager), originally HESSI, was a NASA satellite launched in 2002 to study solar flares in X-rays and gamma rays.
Rhesus macaque
Rhesus macaque (Macaca mulatta), an Asian Old World monkey with the largest natural range of any non-human primate, about 93% human DNA identity, the namesake of the Rh factor, and the most widely used monkey in biomedical research.
Rhetaugh Graves Dumas
Rhetaugh Graves Dumas was an American nurse and psychiatric nursing researcher who became the first woman, nurse, and African American deputy director of the National Institute of Mental Health.
Rhetoric
Rhetoric is the art of persuasive speech, formalized in 5th–4th century BCE Greece; Aristotle defines it as seeing the available means of persuasion via ethos, pathos, and logos, distinguishing it from dialectic.
Rhetoric of Donald Trump
Rhetoric of Donald Trump: scholarly analysis of Trump's distinctive political language, including his rhetorical signature of disruption and demonization, nationalist populism, informal voice, quantified uniqueness versus other presidents, and increased profanity in his second term.
Rhetorical analysis
Rhetorical analysis is a method that examines how a text persuades rather than what it argues, evaluating style, the Aristotelian appeals of ethos, pathos, and logos, and the rhetorical situation.
Rhetorical device
A rhetorical device is a use of language, such as metaphor, irony, or anaphora, designed to evoke a particular response in an audience and to form or strengthen an argument.
Rhetorical question
Rhetorical question: an interrogative posed for effect, not for an answer, conveying indirect force such as assertion of the opposite polarity, command, or evaluation; studied in pragmatics, persuasion experiments, and political discourse.
Rhetorical Stela of Ramesses II
The Rhetorical Stela of Ramesses II is an inscribed Egyptian stela of the pharaoh Ramesses II, praising the king as victorious and pious without reference to a particular event.
Rhetorical treatise
A rhetorical treatise is a systematic written work on persuasion and style, invented in classical Greece to teach speakers how to argue, compose, and move an audience.
Rhett & Link
Rhett & Link (Rhett McLaughlin and Charles Lincoln Neal III) are an American comedy duo and childhood friends from North Carolina who host Good Mythical Morning and run the Mythical studio, with 76 million YouTube subscribers and 27 billion lifetime views.
Rhett Akins
Rhett Akins (Thomas Rhett Akins, born 1969, Valdosta, Georgia) is a country singer-songwriter whose 1990s hits "That Ain't My Truck" and "Don't Get Me Started" preceded a songwriting career of 36 No. 1 hits, Peach Pickers membership, and 2026 Grand Ole Opry induction.
Rhett Butler
Rhett Butler is the blockade-runner antihero of Margaret Mitchell's 1936 novel Gone with the Wind and Clark Gable's role in the 1939 film, Scarlett O'Hara's third husband, father of Bonnie Blue, subject of authorized sequel Rhett Butler's People.
Rhett Marques
Rhett Marques is an American Republican politician serving in the Alabama House of Representatives and running for the U.S. House in Alabama's 2nd District in 2026.
Rhetta Bowers
Rhetta Bowers is an American Democratic member of the Texas House of Representatives from District 113, elected in 2018 as the district's first African American representative.
Rheum officinale root extract
Rheum officinale root extract (Da Huang, rhubarb root) is an anthraquinone-containing herbal extract approved in the EU as a short-term laxative, rejected as a pesticide basic substance in 2015, and poorly supported for chronic kidney disease.
Rheumatic aortic stenosis with insufficiency
Rheumatic aortic stenosis with insufficiency (ICD-11 BB72.0, ICD-10 I06.2) is combined narrowing and leaking of the aortic valve from chronic rheumatic heart disease, usually with fused commissures and concurrent mitral disease.
Rheumatic aortic valve insufficiency
Rheumatic aortic valve insufficiency (rheumatic aortic regurgitation): diastolic aortic valve leakage from rheumatic heart disease after group A streptococcal rheumatic fever; fibrotic restricted leaflets, prevented with penicillin prophylaxis, treated by surgery or TAVR.
Rheumatic aortic valve stenosis
Rheumatic aortic valve stenosis (ICD-11 BB70.0) is aortic valve narrowing from scarring after childhood rheumatic fever, common in Asia and usually with rheumatic mitral disease; treated by valve replacement.
Rheumatic aortitis
Rheumatic aortitis (ICD-11 1B41.10) is aortic wall inflammation from rheumatic disease, chiefly giant cell arteritis and Takayasu arteritis, also rheumatoid arthritis and ankylosing spondylitis, causing aneurysm, stenosis, and regurgitation.
Rheumatic fever
Rheumatic fever, an autoimmune inflammatory disease following group A strep pharyngitis or skin infection by 1-5 weeks, diagnosed by the 2015 Jones criteria, causing rheumatic heart disease.
Rheumatic mitral valve insufficiency
Rheumatic mitral valve insufficiency (rheumatic mitral regurgitation, ICD-11 BB61.0) is leakage of the mitral valve from rheumatic heart disease after Group A streptococcal infection; it predominates in the young and in low-income countries, and valve repair is the operation of choice.
Rheumatic mitral valve stenosis
Rheumatic mitral valve stenosis, also called rheumatic mitral obstruction, is narrowing of the mitral orifice from post-streptococcal valvulitis; valve area ≤1.5 cm² defines severity, treated by percutaneous balloon commissurotomy or surgery.
Rheumatic myocarditis
Rheumatic myocarditis (ICD-10 I09.0, ICD-11 BC42.3) is heart muscle inflammation from autoimmune reaction to group A streptococcal infection in acute rheumatic fever, marked by Aschoff bodies, with debated clinical significance versus valvular disease.
Rheumatic tricuspid valve stenosis
Rheumatic tricuspid valve stenosis (ICD-11 BB80.0) is rheumatic narrowing of the tricuspid valve, almost always with mitral disease (99.3%), causing venous congestion; diagnosed by echocardiography and treated mainly with valve surgery.