42,772 articles
Effective rainfall
Effective rainfall, also called effective precipitation, is the portion of total rainfall useful for a stated purpose, most often crop water supply in the root zone.
Effective sample size
Effective sample size (ESS) is a diagnostic for Markov chain Monte Carlo expressing how many independent draws would carry the same estimation information as autocorrelated draws obtained.
Effective temperature
Effective temperature is the temperature at which a blackbody would radiate the same total power as a source; Earth's is 254.0 K against a surface mean of 15°C.
Effectiveness factor
The effectiveness factor is a dimensionless number in heterogeneous catalysis, the ratio of a porous pellet's actual reaction rate to the rate without internal diffusion limitation.
Effects of climate change
The effects of climate change are the consequences of human-caused global warming: rising temperatures, melting ice, sea level rise, and extreme weather that disrupt health, food systems, and economies.
Effects of climate change on small island countries
Climate change severely affects small island countries, which contribute little to global emissions but face sea-level rise, stronger cyclones, drought, and food and water insecurity.
Effects of Hurricane Beryl in Texas
Hurricane Beryl struck the Texas coast near Matagorda on July 8, 2024 as a Category 1 storm, killing at least 36 people and knocking out power to nearly 2.8 million customers.
Effects of Hurricane Helene in Georgia
Hurricane Helene struck Georgia on September 26 and 27, 2024, causing over 1.5 million power outages, about 34 deaths, and at least $5.5 billion in agricultural losses.
Effects of Hurricane Helene in North Carolina
Hurricane Helene struck western North Carolina on September 26–27, 2024, bringing record rainfall, catastrophic flooding, over 2,000 landslides, 107 deaths, and an estimated $59.6 billion in damage, the costliest storm in state history.
Effects of Hurricane Maria in Puerto Rico
Hurricane Maria struck Puerto Rico as a Category 4 storm on September 20, 2017, causing the longest blackout in U.S. history, an estimated 2,975 deaths, and a mass migration to the mainland.
Effects of Hurricane Sandy in New York
The effects of Hurricane Sandy in New York began on October 29, 2012, when a record storm tide flooded subways and homes, killing 43 people and causing $19 billion in damage.
Effects of nuclear explosions on human health
The effects of nuclear explosions on human health, also called human effects of nuclear explosions, are injuries from blast, thermal radiation, prompt radiation, and fallout, including Acute Radiation Syndrome.
Effects of the Chernobyl disaster
The effects of the Chernobyl disaster are the health and environmental consequences of the 1986 reactor explosion in Ukraine, including thyroid cancers and mass resettlement.
Effects of tropical cyclones
The effects of tropical cyclones span storm surge, extreme winds, heavy rain, and tornadoes that killed 412,644 people from 1980 to 2009 and caused nearly half of all natural disaster losses.
Efficiency
Efficiency, in thermodynamics, is the fraction of energy input to a device converted into useful output, defined for a heat engine as work output divided by heat input.
Efficiency (statistics)
Efficiency in statistics measures how well an estimator or statistical test uses sample information, typically by comparing variance against the Cramér–Rao lower bound, the minimum any unbiased estimator can achieve.
Efficiency droop
Efficiency droop is the reduction in a light-emitting diode's efficiency as current density rises, distinct from thermal droop and attributed mainly to Auger recombination and carrier leakage.
Efficient estimator
An efficient estimator is an unbiased estimator whose variance attains the Cramér–Rao lower bound, the smallest variance any unbiased estimator can have, making it a minimum-variance unbiased estimator.
Efflorescence
Efflorescence is the appearance of white salt crystals on the surface of porous materials like brick, concrete, and stone, formed when dissolved salts crystallize as water evaporates.
Efim Fradkin
Efim Samoilovich Fradkin (Ефим Самойлович Фрадкин; 1924–1999) was a Soviet theoretical physicist at the Lebedev Physics Institute who helped discover the Landau pole and co-founded higher-spin field theory.
Efim Zelmanov
Efim Zelmanov is a Russian-born mathematician, born in 1955 in Khabarovsk, who won the 1994 Fields Medal for solving the restricted Burnside problem in group theory.
Efimov effect
The Efimov effect is a quantum few-body phenomenon, predicted by Vitaly Efimov in the 1970s, in which three particles form infinitely many weakly bound states despite no two binding alone.
Efimov state in helium trimer
The Efimov state in the helium trimer is a weakly bound, extended state of three helium-4 atoms, predicted by Efimov theory in 1977 and observed by Coulomb explosion imaging in 2015.
Efthimios Kaxiras
Efthimios Kaxiras, known as Tim Kaxiras, is a condensed matter physicist who joined Harvard in 1991, holds the Van Vleck professorship, and introduced the term twistronics in 2017.
EGaIn
EGaIn (eutectic gallium–indium) is a liquid-metal alloy of gallium and indium that remains liquid at room temperature and is used in stretchable electronics and soft sensors.
EGARCH model
The EGARCH model, introduced by Daniel B. Nelson in Econometrica in 1991, is a time-series model in which negative and positive shocks of equal size affect volatility differently.
Egbert Brieskorn
Egbert Brieskorn (1936–2013) was a German mathematician, a founder of singularity theory of complex hypersurfaces, whose Brieskorn manifolds gave all 28 differentiable structures on the 7-sphere.
Egbert van Kampen
Egbert van Kampen (Egbert Rudolf van Kampen) was a Dutch mathematician, known for the van Kampen theorem, who worked at Johns Hopkins and died in 1942.
EGFR-TKIs trial
EGFR-TKIs trial (NCT02646020): Chinese phase 2 trial comparing aprepitant, an NK1 antagonist, with desloratadine for EGFR-TKI-induced pruritus in NSCLC; aprepitant gave higher, faster response (57.9% vs 28.0% at week 1) with mild adverse events.
Eggen Moving Groups
Eggen moving groups are groups of nearby stars sharing a common space motion, named for Olin J. Eggen, who proposed and cataloged them from 1958 to 1998.