Classical Cepheids, Type II Cepheids, RR Lyrae variables and Delta Scutis belong to the instability strip which is believed to be driven by Eddington pulsations in helium, while for the Beta Cepheids the pulsation mechanism is unknown.

Cepheid variables are divided into several subclasses which exhibit markedly different masses, ages, and evolutionary histories: Classical Cepheids, Type II Cepheids, Anomalous Cepheids, and Dwarf Cepheids.

Classical Cepheids ( also known as Population I Cepheids, Type I Cepheids, or Delta Cephei variables ) undergo pulsations with very regular periods on the order of days to months.

Classical Cepheids are population I variable stars which are 4 – 20 times more massive than the Sun, and up to 100, 000 times more luminous.

Classical Cepheids are used to determine distances to galaxies within the Local Group and beyond, and are a means by which the Hubble constant can be established.

Classical Cepheids have also been used to clarify many characteristics of our galaxy, such as the Sun's height above the galactic plane and the Galaxy's local spiral structure.

Classical Cepheids are younger and more massive population I stars, whereas Type II Cepheids are older fainter population II stars.

Classical Cepheids and Type II Cepheids follow different period-luminosity relationships.

These unresolved matters have resulted in cited values for the Hubble constant ( established from Classical Cepheids ) ranging between 60 km / s / Mpc and 80 km / s / Mpc.

* Classical Cepheids include: Eta Aquilae, Zeta Geminorum, Beta Doradus, RT Aurigae, Polaris, as well as the namesake Delta Cephei.

Classical Cepheids discovered in the heavily-obscured dust lane of NGC 5128 yield a distance between ~ 3-3. 5 Mpc, depending on the nature of the extinction law adopted and other considerations.

Athens College was established in 1925 by a group of enlightened Greeks ( Emmanuel Benakis and Stephanos Delta among them ) with the support of American philhellenes, including Dr. Bert Hodge, Director of the American School of Classical Studies at Athens.

Its members were Epaminondas Charilaos, President of the Chamber of Commerce and Industry, Bert Hodge Hill, Director of the American School of Classical Studies, Stephanos Delta, retired businessman and treasurer of the Refugee Settlement Commission, Stavros Papadakis, YMCA.

Macready was born in Providence, Rhode Island, and graduated there from Classical High School and, in 1921, from Brown University, where he was a member of Delta Phi fraternity and won a letter as the football team manager.

Classical thermodynamics can consider irreversible processes, but its account in exact terms is restricted to variables that refer only to initial and final states of thermodynamic equilibrium, or to rates of input and output that do not change with time.

Classical variables that do not change upon time reversal include:

Classical variables that time reversal negates include:

On September 10, 1784, Edward Pigott detected the variability of Eta Aquilae, the first known representative of the class of Classical Cepheid variables.

In 1924, Edwin Hubble established the distance to Classical Cepheid variables in the Andromeda Galaxy, and showed that the variables were not members of the Milky Way.

Classical variables are then re-interpreted as quantum operators, while Poisson brackets are replaced by commutators.

Classical test theory is concerned with the relations between the three variables,, and in the population.

Classical variables, predominantly scalar quantities, which do not change upon spatial inversion include:

Classical variables, predominantly vector quantities, which have their sign flipped by spatial inversion include:

The most commonly used languages for representing planning problems, such as STRIPS and PDDL for Classical Planning, are based on state variables.

" Other prestigious architectural awards are the Aga Khan Award for Architecture, the Richard H. Driehaus Prize for Classical Architecture, the Alvar Aalto Medal ( Finland ), the Carlsberg Architecture Prize ( Denmark ), and the Governor General's Awards ( Canada ).

Classical Arminianism, which sees Arminius as the main contributor, and Wesleyan Arminianism, which sees John Wesley as the main contributor, are the two main outlooks on how the system is realistic in detail.

The Amazons (, Amazónes, singular, Amazōn ) are a nation of all-female warriors in Greek mythology and Classical antiquity.

Among Classical Greeks, amazon was given a popular etymology as from a-mazos, " without breast ", connected with an etiological tradition that Amazons had their left breast cut off or burnt out, so they would be able to use a bow more freely and throw spears without the physical limitation and obstruction ; there is no indication of such a practice in works of art, in which the Amazons are always represented with both breasts, although the left is frequently covered ( see photos in article ).

Various conflicting accounts are given in Classical Greek mythology of the birth of Artemis and her twin brother, Apollo.

Beethoven changes the usual pattern of Classical symphonies in placing the scherzo movement before the slow movement ( in symphonies, slow movements are usually placed before scherzi ).

Classical particles with this energy distribution are said to obey Maxwell – Boltzmann statistics.

Classical Chinese astronomy is recorded in the Han period and appears in the form of three schools, which are attributed to astronomers of the Zhanguo period.

The dates of the Classical period in Western music are generally accepted as being between about 1750 and 1820.

Bach and Gluck are often considered to be founders of the Classical style.

* Classical fingerboards are normally flat and without inlaid fret markers, or just have dot inlays on the side of the neck — steel string fingerboards usually have a slight radius and inlays.

Classical approximations to the potential energy surface are employed, as they are computationally less intensive than electronic calculations, to enable longer simulations of molecular dynamics.

Classical liberalism holds that individual rights are natural, inherent, or inalienable, and exist independently of government.

They are the Assakenoi and Aspasioi of the Classical writings, and the Ashvakayanas and Ashvayanas in Pāṇini's Ashtadhyayi.

For example, in one of the Four Great Classical Novels of China, The Dream of the Red Chamber ( believed to be a semi-autobiographical account of author Cao Xueqin's own family life ), three generations of the Jia family are supported by one favorite concubine of the Emperor.

The Letters are available in the Loeb Classical Library, translated by Allen Rogers Benner and Francis H. Fobes ( 1949 ).

Whilst critical theorists usually are defined as Marxist intellectuals, their tendency to denounce Marxist concepts, and to synthesise Marxian analysis with other sociologic and philosophic traditions has been attacked as revisionism, by Classical, Orthodox, and Analytical Marxists, and by Marxist-Leninist philosophers.

Today clavichords are played primarily by Renaissance, Baroque, and Classical music enthusiasts.

Classical objects are defined as not resonant and not being currently scattered by Neptune.

Since there are no punctuation marks in Classical Chinese, it can be difficult to conclusively determine where one sentence ends and the next begins.

Classical training methods vary by country: many of the major European countries are associated with specific methods ( e. g., the Edouard Nanny method in France or the Franz Simandl method in Germany ).

Classical analog filters are IIR filters, and classical filter theory centers on the determination of transfer functions given by low order rational functions, which can be synthesized using the same small number of reactive components.

Classical empiricists generally held that such reports are indubitable and incorrigible and therefore worthy of serving as epistemologically basic propositions.

In the written style known as kanbun, which is the Japanese approximation of Classical Chinese, small marks called kunten are sometimes added as reading aids.