Glossary

Term	Definition
Solar Radiation	Radiation emitted by the Sun. It is also referred to as short-wave radiation. Solar radiation has a distinctive range of wavelengths (spectrum) determined by the temperature of the Sun.
Spike Protein	Spike proteins are large, surface-projecting glycoproteins found on enveloped viruses, notably coronaviruses, which form trimmer structures crucial for host cell attachment and entry.
Statistical Significance	Observation, based on the application of a statistical test, that a relationship probably is not due to pure chance. The probability is stated (e.g., p < 0.05) and the results are said to be statistically significant.
Statistically Significant	Describing a result that is likely, not due to chance, but rather due to a real process. Scientists define a result as "significant" if it would happen by chance less than 5% of the time (shown as p < 0.05). The more significant a result is the lower its p-value. Statistical significance is an important way for scientists to deal with uncertainty.
Storm Surge	An abnormal rise in sea level accompanying a hurricane or other intense storm, whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone.
Strain	A specific version of an organism. Many agents causing diseases, including HIV/AIDS and hepatitis, have multiple strains.
Stratosphere	Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles to 15 km at the equator and an upper boundary of approximately 50 km.
T-cell	T cells are a type of white blood cell (lymphocyte) essential to the adaptive immune system, maturing in the thymus to fight infections, viruses, and cancer. They identify pathogens via surface receptors.
Theory	A well-substantiated, comprehensive explanation for a set of observations or phenomena, built from numerous tested hypotheses, facts, and laws, forming a robust framework that explains why something happens. Theories are repeatedly tested, supported by extensive evidence, and can be modified if new evidence emerges, making them the most reliable form of scientific knowledge. Note: A scientific theory isn't a hypothesis or a guess. It doesn't correspond to the casual and every-day use of the term "theory". A scientific theory is the very best explanation we have to fit the available data.
Thermohaline Circulation	Large-scale density-driven circulation in the ocean, caused by differences in temperature and salinity. In the North Atlantic the thermohaline circulation consists of warm surface water flowing northward and cold deep water flowing southward, resulting in a net poleward transport of heat.