42,772 articles
Kernel (statistics)
In statistics, a kernel is a weighting function used to build nonparametric estimates from data, introduced for density estimation by Rosenblatt in 1956; the word also names Markov transition kernels.
Kernel association test
A kernel association test is a set-based statistical test in genetics that regresses a trait on many variants in a genomic region at once; SKAT is the best known.
Kernel density estimation
Kernel density estimation, or Parzen windowing, is a nonparametric statistical method for estimating the probability density function of a distribution from data by placing a smooth kernel around each observed point.
Kernel principal component analysis
Kernel principal component analysis (kernel PCA) is a nonlinear dimensionality reduction method that performs PCA in a high-dimensional kernel-defined feature space, introduced by Schölkopf, Smola, and Müller in 1998.
Kernel regression
Kernel regression is a nonparametric method for estimating a regression function from data without a fixed parametric form, using weighted averages such as the Nadaraya–Watson estimator.
Kernite
Kernite, formerly rasorite, is a hydrated sodium borate mineral and one of the world's principal ores of boron, discovered in Kern County, California, in 1925.
Kerogen
Kerogen is the insoluble organic matter in sedimentary rocks that generates petroleum and natural gas when buried and heated, and is Earth's most abundant organic matter.
Kerosene
Kerosene is a light petroleum distillate of hydrocarbons with 9 to 16 carbon atoms, used for heating, lighting, and jet fuel, called paraffin in the United Kingdom.
Kerr effect
The Kerr effect, also called the Kerr electro-optic effect or Kerr nonlinearity, is the electric-field-induced birefringence proportional to the square of the field, discovered by John Kerr in 1875.
Kerr metric
The Kerr metric, or Kerr solution, is the exact vacuum Einstein solution describing the spacetime around a spinning, uncharged black hole, found by Roy P. Kerr in 1963.
Kerr-lens mode-locked thin-disk oscillator
A Kerr-lens mode-locked thin-disk oscillator is a femtosecond solid-state laser, first demonstrated in 2012 at the Max Planck Institute of Quantum Optics, delivering over 200 W of average power without external amplification.
Kerr–Newman metric
The Kerr–Newman metric is the exact Einstein–Maxwell solution describing the spacetime around a stationary, rotating, electrically charged mass, defined by its mass, charge, and spin and published in 1965.
Kerr–Schild form
The Kerr–Schild form is an ansatz in general relativity writing a metric as flat spacetime plus a null-vector term, introduced by Kerr and Schild in 1965.
Kerry Emanuel
Kerry Emanuel, born 1955, is an American climate scientist and Professor Emeritus at MIT, the first to predict that hurricanes would intensify as the climate warms.
Kerry J. Vahala
Kerry J. Vahala is an American applied physicist and electrical engineer at Caltech, known for ultra-high-Q optical microresonators on semiconductor chips, optical frequency microcombs, and cavity optomechanics.
Kerry Sieh
Kerry Sieh is an American geophysicist known for proposing the buried Australasian impact crater in southern Laos and for founding the Earth Observatory of Singapore.
Kerson Huang
Kerson Huang (1928–2016) was a Chinese-American theoretical physicist and MIT professor emeritus whose 1957 hard-sphere Bose gas work with C. N. Yang produced the Lee–Huang–Yang correction, and whose statistical mechanics textbooks remained in worldwide use.
Ketamine
Ketamine is an arylcyclohexylamine compound synthesized in 1962 by Calvin Stevens at Parke-Davis, sold as the hydrochloride salt and controlled as a Schedule III substance in the United States.
Ketene
Ketene, also known as ethenone (CH₂=C=O), is the simplest ketene, a colorless, flammable, highly reactive gas made from acetic acid and used to produce acetic anhydride.
Ketene cycloaddition
Ketene cycloaddition is the reaction in which a ketene combines with an alkene, imine, or carbonyl compound to form a ring, giving cyclobutanones and β-lactams.
Keto acid
A keto acid, also called an oxoacid, is an organic compound containing both a ketone and a carboxylic acid group, central to metabolism and organic synthesis.
Ketogenic amino acid
A ketogenic amino acid is one whose degradation yields acetyl-CoA or acetoacetate, which form ketone bodies but not glucose; leucine and lysine are the only two.
Ketone
A ketone, also called an alkanone, is an organic compound in which a carbonyl group is bonded to two carbon atoms; the smallest, acetone, is a common solvent.
Kettle (landform)
A kettle, also called a kettle hole, is a bowl-shaped depression in glacial deposits formed when a buried ice block melts and overlying sediment collapses.
Ketu (केतु) (mythology)
Ketu (केतु) is one of the nine planetary deities of Hindu astrology, personifying the descending lunar node and paired with Rahu; the two are linked with eclipses.
Keuper
The Keuper is the uppermost of the three lithostratigraphic groups of the Germanic Trias, above the Muschelkalk, consisting mainly of variegated claystones, sandstones, and gypsum deposited in continental, semi-arid conditions.
Kevin Burgess (chemist)
Kevin Burgess is a chemist and Rachal Chair in Chemistry at Texas A&M University who designs peptidomimetics, small molecules imitating protein surfaces, targeting receptors like TrkC in metastatic cancer.
Kevin Burke (geophysicist)
Kevin Burke (1929–2018) was a British-born geologist and geophysicist, professor at the University of Houston, who coined the term Wilson cycle and studied mantle plumes.
Kevin Burton
Kevin W. Burton is an isotope geochemist and Professor of Geochemistry at Durham University since 2007, known for applying rhenium-osmium isotope measurements to mantle rocks and ocean sediments.
Kevin C. Jones
Kevin C. Jones is a British environmental chemist, Distinguished Professor at Lancaster University, known for research on persistent organic pollutants and for establishing passive air sampling networks across Europe.