Aperture (antenna)In electromagnetics and antenna theory, the aperture of an antenna is defined as "A surface, near or on an antenna, on which it is convenient to make assumptions regarding the field values for the purpose of computing fields at external points. The aperture is often taken as that portion of a plane surface near the antenna, perpendicular to the direction of maximum radiation, through which the major part of the radiation passes.
Minority rightsMinority rights are the normal individual rights as applied to members of racial, ethnic, class, religious, linguistic or gender and sexual minorities, and also the collective rights accorded to any minority group. Civil-rights movements often seek to ensure that individual rights are not denied on the basis of membership in a minority group. Such civil-rights advocates include the global women's-rights and global LGBT-rights movements, and various racial-minority rights movements around the world (such as the Civil Rights Movement in the United States).
Minority languageA minority language is a language spoken by a minority of the population of a territory. Such people are termed linguistic minorities or language minorities. With a total number of 196 sovereign states recognized internationally (as of 2019) and an estimated number of roughly 5,000 to 7,000 languages spoken worldwide, the vast majority of languages are minority languages in every country in which they are spoken. Some minority languages are simultaneously also official languages, such as Irish in Ireland or the numerous indigenous languages of Bolivia.
HeatIn thermodynamics, heat is the thermal energy transferred between systems due to a temperature difference. In colloquial use, heat sometimes refers to thermal energy itself. An example of formal vs. informal usage may be obtained from the right-hand photo, in which the metal bar is "conducting heat" from its hot end to its cold end, but if the metal bar is considered a thermodynamic system, then the energy flowing within the metal bar is called internal energy, not heat.
Model minorityThe term model minority refers to a minority demographic, defined by factors such as ethnicity, race, or religion, whose members are perceived to achieve a higher socioeconomic status in comparison to the overall population average. Consequently, these groups are often regarded as a reference group for comparison to external groups (outgroups). This success is typically assessed through metrics including educational attainment, representation within managerial and professional occupations, household income, and various other socioeconomic indicators such as criminal activity and strong family and marital stability.
Economic equilibriumIn economics, economic equilibrium is a situation in which economic forces such as supply and demand are balanced and in the absence of external influences the (equilibrium) values of economic variables will not change. For example, in the standard text perfect competition, equilibrium occurs at the point at which quantity demanded and quantity supplied are equal. Market equilibrium in this case is a condition where a market price is established through competition such that the amount of goods or services sought by buyers is equal to the amount of goods or services produced by sellers.
General equilibrium theoryIn economics, general equilibrium theory attempts to explain the behavior of supply, demand, and prices in a whole economy with several or many interacting markets, by seeking to prove that the interaction of demand and supply will result in an overall general equilibrium. General equilibrium theory contrasts with the theory of partial equilibrium, which analyzes a specific part of an economy while its other factors are held constant.
Low frequencyLow frequency (LF) is the ITU designation for radio frequencies (RF) in the range of 30–300 kHz. Since its wavelengths range from 10–1 km, respectively, it is also known as the kilometre band or kilometre wave. LF radio waves exhibit low signal attenuation, making them suitable for long-distance communications. In Europe and areas of Northern Africa and Asia, part of the LF spectrum is used for AM broadcasting as the "longwave" band. In the western hemisphere, its main use is for aircraft beacon, navigation (LORAN), information, and weather systems.
Chemical equilibriumIn a chemical reaction, chemical equilibrium is the state in which both the reactants and products are present in concentrations which have no further tendency to change with time, so that there is no observable change in the properties of the system. This state results when the forward reaction proceeds at the same rate as the reverse reaction. The reaction rates of the forward and backward reactions are generally not zero, but they are equal. Thus, there are no net changes in the concentrations of the reactants and products.
Equilibrium constantThe equilibrium constant of a chemical reaction is the value of its reaction quotient at chemical equilibrium, a state approached by a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency towards further change. For a given set of reaction conditions, the equilibrium constant is independent of the initial analytical concentrations of the reactant and product species in the mixture.
