Density-functional theory (DFT) is a computational quantum mechanical modelling method used in physics, chemistry and materials science to investigate the electronic structure (or nuclear structure) (principally the ground state) of many-body systems, in particular atoms, molecules, and the condensed phases. Using  this theory, the properties of a many-electron system can be determined by using functionals, i.e. functions of another function.  In the case of DFT, these are functionals of the spatially dependent electron density. DFT is among the most popular and versatile methods available in condensed-matter physics, computational physics, and computational chemistry.

DFT has been very popular for calculations in solid-state physics since the 1970s. However, DFT was not considered accurate enough for calculations in quantum chemistry until the 1990s, when the approximations used in the theory were greatly refined to better model the exchange and correlation interactions. Computational costs are relatively low when compared to traditional methods, such as exchange only Hartree–Fock theory and its descendants that include electron correlation. Since, DFT has become an important tool for methods of nuclear spectroscopy such as Mössbauer spectroscopy or perturbed angular correlation, in order to understand the origin of specific electric field gradients in crystals.

Despite recent improvements, there are still difficulties in using density functional theory to properly describe: intermolecular interactions (of critical importance to understanding chemical reactions), especially van der Waals forces (dispersion); charge transfer excitations; transition states, global potential energy surfaces, dopant interactions and some strongly correlated systems; and in calculations of the band gap and ferromagnetism in semiconductors. The incomplete treatment of dispersion can adversely affect the accuracy of DFT (at least when used alone and uncorrected) in the treatment of systems which are dominated by dispersion (e.g. interacting noble gas atoms) or where dispersion competes significantly with other effects (e.g. in biomolecules). The development of new DFT methods designed to overcome this problem, by alterations to the functional or by the inclusion of additive terms, is a current research topic.  Classical density functional theory uses a similar formalism to calculate the properties of non-uniform classical fluids.

Despite the current popularity of these alterations or of the inclusion of additional terms, they are reported to stray away from the search for the exact functional. Further, DFT potentials obtained with adjustable parameters are no longer true DFT potentials, given that they are not functional derivatives of the  exchange correlation energy with respect to the charge density. Consequently, it is not clear if the second theorem of DFT holds in such conditions.

Overview of method
In the context of computational materials science, ab initio (from first principles) DFT calculations allow the prediction and calculation of material behavior on the basis of quantum mechanical considerations, without requiring higher-order parameters such as fundamental material properties. In contemporary DFT techniques the electronic structure is evaluated using a potential acting on the system's electrons. This DFT potential is constructed as the sum of external potentials , which is determined solely by the structure and the elemental composition of the system, and an effective potential , which represents interelectronic interactions. Thus, a problem for a representative supercell of a material with  electrons can be studied as a set of  one-electron Schrödinger-like equations, which are also known as Kohn–Sham equations.

Origins
Although density functional theory has its  roots in the Thomas–Fermi model for the electronic structure of materials, DFT was first put on a firm theoretical footing by Walter Kohn and Pierre Hohenberg in the framework of the two Hohenberg–Kohn theorems (HK). The original HK theorems held only for non-degenerate ground states in the absence of a magnetic field, although they have since been generalized to encompass these.

The first HK theorem demonstrates that the ground-state properties of a many-electron system are uniquely determined by an electron density that depends on only three spatial coordinates. It set down the groundwork for reducing the many-body problem of  electrons with  spatial coordinates to three spatial coordinates, through the use of functionals of the electron density. This theorem has since been extended to the time-dependent domain to develop time-dependent density functional theory (TDDFT), which can be used to describe excited states.

The second HK theorem defines an energy functional for the system and proves that the ground-state electron density minimizes this energy functional.

In work that later won them the Nobel prize in chemistry, the HK theorem was further developed by Walter Kohn and Lu Jeu Sham to produce Kohn–Sham DFT (KS DFT). Within this framework, the intractable many-body problem of interacting electrons in a static external potential is reduced to a tractable problem of noninteracting electrons moving in an effective potential. The effective potential includes the external potential and the effects of the Coulomb interactions between the electrons, e.g., the exchange and correlation interactions. Modeling the latter two interactions becomes the difficulty within KS DFT. The simplest approximation is the local-density approximation (LDA), which is based upon exact exchange energy for a uniform electron gas, which can be obtained from the Thomas–Fermi model, and from fits to the correlation energy for a uniform electron gas. Non-interacting systems are relatively easy to solve, as the wavefunction can be represented as a Slater determinant of orbitals. Further, the kinetic energy functional of such a system is known exactly. The exchange–correlation part of the total energy functional remains unknown and must be approximated.

Another approach, less popular than KS DFT but arguably more closely related to the spirit of the original HK theorems, is orbital-free density functional theory (OFDFT), in which approximate functionals are also used for the kinetic energy of the noninteracting system.

Derivation and formalism
As usual in many-body electronic structure calculations, the nuclei of the treated molecules or clusters are seen as fixed (the Born–Oppenheimer approximation), generating a static external potential , in which the electrons are moving. A stationary electronic state is then described by a wavefunction  satisfying the many-electron time-independent Schrödinger equation

where, for the -electron system,  is the Hamiltonian,  is the total energy,  is the kinetic energy,  is the potential energy from the external field due to positively charged nuclei, and  is the electron–electron interaction energy. The operators  and  are called universal operators, as they are the same for any -electron system, while  is system-dependent. This complicated many-particle equation is not separable into simpler single-particle equations because of the interaction term .

There are many sophisticated methods for solving the many-body Schrödinger equation based on the expansion of the wavefunction in Slater determinants. While the simplest one is the Hartree–Fock method, more sophisticated approaches are usually categorized as post-Hartree–Fock methods. However, the problem with these methods is the huge computational effort, which makes it virtually impossible to apply them efficiently to larger, more complex systems.

Here DFT provides an appealing alternative, being much more versatile, as it provides a way to systematically map the many-body problem, with , onto a single-body problem without . In DFT the key variable is the electron density , which for a normalized  is given by

This relation can be reversed, i.e., for a given ground-state density  it is possible, in principle, to calculate the corresponding ground-state wavefunction . In other words,  is a unique functional of ,

and consequently the ground-state expectation value of an observable  is also a functional of :

In particular, the ground-state energy is a functional of :

where the contribution of the external potential  can be written explicitly in terms of the ground-state density :

More generally, the contribution of the external potential  can be written explicitly in terms of the density :

The functionals  and  are called universal functionals, while  is called a non-universal functional, as it depends on the system under study. Having specified a system, i.e., having specified , one then has to minimize the functional

with respect to , assuming one has reliable expressions for  and . A successful minimization of the energy functional will yield the ground-state density  and thus all other ground-state observables.

The variational problems of minimizing the energy functional  can be solved by applying the Lagrangian method of undetermined multipliers. First, one considers an energy functional that does not explicitly have an electron–electron interaction energy term,

where  denotes the kinetic-energy operator, and  is an effective potential in which the particles are moving. Based on , Kohn–Sham equations of this auxiliary noninteracting system can be derived:

which yields the orbitals  that reproduce the density  of the original many-body system

The effective single-particle potential can be written as

where  is the external potential, the second term is the Hartree term describing the electron–electron Coulomb repulsion, and the last term  is the exchange–correlation potential. Here,  includes all the many-particle interactions. Since the Hartree term and  depend on , which depends on the , which in turn depend on , the problem of solving the Kohn–Sham equation has to be done in a self-consistent (i.e., iterative) way. Usually one starts with an initial guess for , then calculates the corresponding  and solves the Kohn–Sham equations for the . From these one calculates a new density and starts again. This procedure is then repeated until convergence is reached. A non-iterative approximate formulation called Harris functional DFT is an alternative approach to this.

Notes
 The one-to-one correspondence between electron density and single-particle potential is not so smooth. It contains kinds of non-analytic structure.  contains kinds of singularities, cuts and branches. This may indicate a limitation of our hope for representing exchange–correlation functional in a simple analytic form.
 It is possible to extend the DFT idea to the case of the Green function  instead of the density . It is called as Luttinger–Ward functional (or kinds of similar functionals), written as . However,  is determined not as its minimum, but as its extremum. Thus we may have some theoretical and practical difficulties.
 There is no one-to-one correspondence between one-body density matrix  and the one-body potential . (All the eigenvalues of  are 1.) In other words, it ends up with a theory similar to the Hartree–Fock (or hybrid) theory.

Relativistic formulation (ab initio functional forms)
The same theorems can be proven in the case of relativistic electrons, thereby providing generalization of DFT for the relativistic case. Unlike the nonrelativistic theory, in the relativistic case it is possible to derive a few exact and explicit formulas for the relativistic density functional.

Let one consider an electron in a hydrogen-like ion obeying the relativistic Dirac equation. The Hamiltonian  for a relativistic electron moving in the Coulomb potential can be chosen in the following form (atomic units are used):

where  is the Coulomb potential of a pointlike nucleus,  is a momentum operator of the electron, and ,  and  are the elementary charge, electron mass and the speed of light respectively, and finally  and  are a set of Dirac 2 × 2 matrices:

To find out the eigenfunctions and corresponding energies, one solves the eigenfunction equation

where  is a four-component wavefunction, and  is the associated eigenenergy. It is demonstrated in Brack (1983) that application of the virial theorem to the eigenfunction equation produces the following formula for the eigenenergy of any bound state:

and analogously, the virial theorem applied to the eigenfunction equation with the square of the Hamiltonian yields

It is easy to see that both of the above formulae represent density functionals. The former formula can be easily generalized for the multi-electron case.

One may observe that both of the functionals written above do not have extremals, of course, if a reasonably wide set of functions is allowed for variation. Nevertheless, it is possible to design a density functional with desired extremal properties out of those ones. Let us make it in the following way:

where  in Kronecker delta symbol of the second term denotes any extremal for the functional represented by the first term of the functional . The second term amounts to zero for any function that is not an extremal for the first term of functional . To proceed further we'd like to find Lagrange equation for this functional. In order to do this, we should allocate a linear part of functional increment when the argument function is altered:

Deploying written above equation, it is easy to find the following formula for functional derivative:

where , and , and  is a value of potential at some point, specified by support of variation function , which is supposed to be infinitesimal. To advance toward Lagrange equation, we equate functional derivative to zero and after simple algebraic manipulations arrive to the following equation:

Apparently, this equation could have solution only if . This last condition provides us with Lagrange
equation for functional , which could be finally written down in the following form:

Solutions of this equation represent extremals for functional . It's easy to see that all real densities,
that is, densities corresponding to the bound states of the system in question, are solutions of written above equation, which could be called the Kohn–Sham equation in this particular case. Looking back onto the definition of the functional , we clearly see that the functional produces energy of the system for appropriate density, because the first term amounts to zero for such density and the second one delivers the energy value.

Approximations (exchange–correlation functionals)
The major problem with DFT is that the exact functionals for exchange and correlation are not known, except for the free-electron gas. However, approximations exist which permit the calculation of certain physical quantities quite accurately. One of the simplest approximations is the local-density approximation (LDA), where the functional depends only on the density at the coordinate where the functional is evaluated:

The local spin-density approximation (LSDA) is a straightforward generalization of the LDA to include electron spin:

In LDA, the exchange–correlation energy is typically separated into the exchange part and the correlation part: . The exchange part is called the Dirac (or sometimes Slater) exchange, which takes the form . There are, however, many mathematical forms for the correlation part. Highly accurate formulae for the correlation energy density  have been constructed from quantum Monte Carlo simulations of jellium. A simple first-principles correlation functional has been recently proposed as well. Although unrelated to the Monte Carlo simulation, the two variants provide comparable accuracy.

The LDA assumes that the density is the same everywhere. Because of this, the LDA has a tendency to underestimate the exchange energy and over-estimate the correlation energy. The errors due to the exchange and correlation parts tend to compensate each other to a certain degree. To correct for this tendency, it is common to expand in terms of the gradient of the density in order to account for the non-homogeneity of the true electron density. This allows corrections based on the changes in density away from the coordinate. These expansions are referred to as generalized gradient approximations (GGA) and have the following form:

Using the latter (GGA), very good results for molecular geometries and ground-state energies have been achieved.

Potentially more accurate than the GGA functionals are the meta-GGA functionals, a natural development after the GGA (generalized gradient approximation). Meta-GGA DFT functional in its original form includes the second derivative of the electron density (the Laplacian), whereas GGA includes only the density and its first derivative in the exchange–correlation potential.

Functionals of this type are, for example, TPSS and the Minnesota Functionals. These functionals include a further term in the expansion, depending on the density, the gradient of the density and the Laplacian (second derivative) of the density.

Difficulties in expressing the exchange part of the energy can be relieved by including a component of the exact exchange energy calculated from Hartree–Fock theory. Functionals of this type are known as hybrid functionals.

Generalizations to include magnetic fields

The DFT formalism described above breaks down, to various degrees, in the presence of a vector potential, i.e. a magnetic field. In such a situation, the one-to-one mapping between the ground-state electron density and wavefunction is lost. Generalizations to include the effects of magnetic fields have led to two different theories: current density functional theory (CDFT) and magnetic field density functional theory (BDFT). In both these theories, the functional used for the exchange and correlation must be generalized to include more than just the electron density. In current density functional theory, developed by Vignale and Rasolt, the functionals become dependent on both the electron density and the paramagnetic current density. In magnetic field density functional theory, developed by Salsbury, Grayce and Harris, the functionals depend on the electron density and the magnetic field, and the functional form can depend on the form of the magnetic field. In both of these theories it has been difficult to develop functionals beyond their equivalent to LDA, which are also readily implementable computationally.

Applications

In general, density functional theory finds increasingly broad application in chemistry and materials science for the interpretation and prediction of complex system behavior at an atomic scale. Specifically, DFT computational methods are applied for synthesis-related systems and processing parameters. In such systems, experimental studies are often encumbered by inconsistent results and non-equilibrium conditions. Examples of contemporary DFT applications include studying the effects of dopants on phase transformation behavior in oxides, magnetic behavior in dilute magnetic semiconductor materials, and the study of magnetic and electronic behavior in ferroelectrics and dilute magnetic semiconductors. It has also been shown that DFT gives good results in the prediction of sensitivity of some nanostructures to environmental pollutants like sulfur dioxide or acrolein, as well as prediction of mechanical properties.

In practice, Kohn–Sham theory can be applied in several distinct ways, depending on what is being investigated. In solid-state calculations, the local density approximations are still commonly used along with plane-wave basis sets, as an electron-gas approach is more appropriate for electrons delocalised through an infinite solid. In molecular calculations, however, more sophisticated functionals are needed, and a huge variety of exchange–correlation functionals have been developed for chemical applications. Some of these are inconsistent with the uniform electron-gas approximation; however, they must reduce to LDA in the electron-gas limit. Among physicists, one of the most widely used functionals is the revised Perdew–Burke–Ernzerhof exchange model (a direct generalized gradient parameterization of the free-electron gas with no free parameters); however, this is not sufficiently calorimetrically accurate for gas-phase molecular calculations. In the chemistry community, one popular functional is known as BLYP (from the name Becke for the exchange part and Lee, Yang and Parr for the correlation part). Even more widely used is B3LYP, which is a hybrid functional in which the exchange energy, in this case from Becke's exchange functional, is combined with the exact energy from Hartree–Fock theory. Along with the component exchange and correlation funсtionals, three parameters define the hybrid functional, specifying how much of the exact exchange is mixed in. The adjustable parameters in hybrid functionals are generally fitted to a "training set" of molecules. Although the results obtained with these functionals are usually sufficiently accurate for most applications, there is no systematic way of improving them (in contrast to some of the traditional wavefunction-based methods like configuration interaction or coupled cluster theory). In the current DFT approach it is not possible to estimate the error of the calculations without comparing them to other methods or experiments.

Density functional theory is generally highly accurate but highly computationally-expensive. In recent years, DFT has been used with machine learning techniques - especially graph neural networks - to create machine learning potentials. These graph neural networks approximate DFT, with the aim of achieving similar accuracies with much less computation, and are especially beneficial for large systems. They are trained using DFT-calculated properties of a known set of molecules. Researchers have been trying to approximate DFT with machine learning for decades, but have only recently made good estimators. Breakthroughs in model architecture and data preprocessing that more heavily encoded theoretical knowledge, especially regarding symmetries and invariances, have enabled huge leaps in model performance. Using backpropagation, the process by which neural networks learn from training errors, to extract meaningful information about forces and densities, has similarly improved machine learning potentials accuracy. By 2023, for example, the DFT approximator Matlantis could simulate 72 elements, handle up to 20,000 atoms at a time, and execute calculations up to 20,000,000 times faster than DFT with similar accuracy, showcasing the power of DFT approximators in the artificial intelligence age. ML approximations of DFT have historically faced substantial transferability issues, with models failing to generalize potentials from some types of elements and compounds to others; improvements in architecture and data have slowly mitigated, but not eliminated, this issue. For very large systems, electrically nonneutral simulations, and intricate reaction pathways, DFT approximators often remain insufficiently computationally-lightweight or insufficiently accurate.

Thomas–Fermi model
The predecessor to density functional theory was the Thomas–Fermi model, developed independently by both Llewellyn Thomas and Enrico Fermi in 1927. They used a statistical model to approximate the distribution of electrons in an atom. The mathematical basis postulated that electrons are distributed uniformly in phase space with two electrons in every  of volume. For each element of coordinate space volume  we can fill out a sphere of momentum space up to the Fermi momentum

Equating the number of electrons in coordinate space to that in phase space gives

Solving for  and substituting into the classical kinetic energy formula then leads directly to a kinetic energy represented as a functional of the electron density:

where

As such, they were able to calculate the energy of an atom using this kinetic-energy functional combined with the classical expressions for the nucleus–electron and electron–electron interactions (which can both also be represented in terms of the electron density).

Although this was an important first step, the Thomas–Fermi equation's accuracy is limited because the resulting kinetic-energy functional is only approximate, and because the method does not attempt to represent the exchange energy of an atom as a conclusion of the Pauli principle. An exchange-energy functional was added by Paul Dirac in 1928.

However, the Thomas–Fermi–Dirac theory remained rather inaccurate for most applications. The largest source of error was in the representation of the kinetic energy, followed by the errors in the exchange energy, and due to the complete neglect of electron correlation.

Edward Teller (1962) showed that Thomas–Fermi theory cannot describe molecular bonding. This can be overcome by improving the kinetic-energy functional.

The kinetic-energy functional can be improved by adding the von Weizsäcker (1935) correction:

Hohenberg–Kohn theorems
The Hohenberg–Kohn theorems relate to any system consisting of electrons moving under the influence of an external potential.

Theorem 1. The external potential (and hence the total energy), is a unique functional of the electron density.

 If two systems of electrons, one trapped in a potential  and the other in , have the same ground-state density , then  is necessarily a constant.

 Corollary 1: the ground-state density uniquely determines the potential and thus all properties of the system, including the many-body wavefunction. In particular, the HK functional, defined as , is a universal functional of the density (not depending explicitly on the external potential).
Corollary 2: In light of the fact that the sum of the occupied energies provides the energy content of the Hamiltonian, a unique functional of the ground state charge density, the spectrum of the Hamiltonian is also a unique functional of the ground state charge density.

Theorem 2. The functional that delivers the ground-state energy of the system gives the lowest energy if and only if the input density is the true ground-state density.

 In other words, the energy content of the Hamiltonian reaches its absolute minimum, i.e., the ground state, when the charge density is that of the ground state.

 For any positive integer  and potential , a density functional  exists such that

 reaches its minimal value at the ground-state density of  electrons in the potential . The minimal value of  is then the ground-state energy of this system.

Pseudo-potentials

The many-electron Schrödinger equation can be very much simplified if electrons are divided in two groups: valence electrons and inner core electrons. The electrons in the inner shells are strongly bound and do not play a significant role in the chemical binding of atoms; they also partially screen the nucleus, thus forming with the nucleus an almost inert core. Binding properties are almost completely due to the valence electrons, especially in metals and semiconductors. This separation suggests that inner electrons can be ignored in a large number of cases, thereby reducing the atom to an ionic core that interacts with the valence electrons. The use of an effective interaction, a pseudopotential, that approximates the potential felt by the valence electrons, was first proposed by Fermi in 1934 and Hellmann in 1935. In spite of the simplification pseudo-potentials introduce in calculations, they remained forgotten until the late 1950s.

Ab initio pseudo-potentials

A crucial step toward more realistic pseudo-potentials was given by Topp and Hopfield, who suggested that the pseudo-potential should be adjusted such that they describe the valence charge density accurately. Based on that idea, modern pseudo-potentials are obtained inverting the free-atom Schrödinger equation for a given reference electronic configuration and forcing the pseudo-wavefunctions to coincide with the true valence wavefunctions beyond a certain distance . The pseudo-wavefunctions are also forced to have the same norm (i.e., the so-called norm-conserving condition) as the true valence wavefunctions and can be written as

where  is the radial part of the wavefunction with angular momentum , and PP and AE denote the pseudo-wavefunction and the true (all-electron) wavefunction respectively. The index  in the true wavefunctions denotes the valence level. The distance  beyond which the true and the pseudo-wavefunctions are equal is also dependent on .

Electron smearing
The electrons of a system will occupy the lowest Kohn–Sham eigenstates up to a given energy level according to the Aufbau principle. This corresponds to the steplike Fermi–Dirac distribution at absolute zero. If there are several degenerate or close to degenerate eigenstates at the Fermi level, it is possible to get convergence problems, since very small perturbations may change the electron occupation. One way of damping these oscillations is to smear the electrons, i.e. allowing fractional occupancies. One approach of doing this is to assign a finite temperature to the electron Fermi–Dirac distribution. Other ways is to assign a cumulative Gaussian distribution of the electrons or using a Methfessel–Paxton method.

Classical density functional theory
Classical density functional theory is a classical statistical method to investigate the properties of many-body systems consisting of interacting molecules, macromolecules, nanoparticles or microparticles. The classical non-relativistic method is correct for classical fluids with particle velocities less than the speed of light and thermal de Broglie wavelength smaller than the distance between particles. The theory is based on the calculus of variations of a thermodynamic functional, which is a function of the spatially dependent density function of particles, thus the name. The same name is used for quantum DFT, which is the theory to calculate the electronic structure of electrons based on spatially dependent electron density with quantum and relativistic effects. Classical DFT is a popular and useful method to study fluid phase transitions, ordering in complex liquids, physical characteristics of interfaces and nanomaterials. Since the 1970s it has been applied to the fields of materials science, biophysics, chemical engineering and civil engineering. Computational costs are much lower than for molecular dynamics simulations, which provide similar data and a more detailed description but are limited to small systems and short time scales. Classical DFT is valuable to interpret and test numerical results and to define trends although details of the precise motion of the particles are lost due to averaging over all possible particle trajectories. As in electronic systems, there are fundamental and numerical difficulties in using DFT to quantitatively describe the effect of intermolecular interaction on structure, correlations and thermodynamic properties.

Classical DFT addresses the difficulty of describing thermodynamic equilibrium states of many-particle systems with nonuniform density. Classical DFT has its roots in theories such as the van der Waals theory for the equation of state and the virial expansion method for the pressure. In order to account for correlation in the positions of particles the direct correlation function was introduced as the effective interaction between two particles in the presence of a number of surrounding particles by Leonard Ornstein and Frits Zernike in 1914. The connection to the density pair distribution function was given by the Ornstein–Zernike equation. The importance of correlation for thermodynamic properties was explored through density distribution functions. The functional derivative was introduced to define the distribution functions of classical mechanical systems. Theories were developed for simple and complex liquids using the ideal gas as a basis for the free energy and adding molecular forces as a second-order perturbation. A term in the gradient of the density was added to account for non-uniformity in density in the presence of external fields or surfaces. These theories can be considered precursors of DFT.

To develop a formalism for the statistical thermodynamics of non-uniform fluids functional differentiation was used extensively by Percus and Lebowitz (1961), which led to the Percus–Yevick equation linking the density distribution function and the direct correlation. Other closure relations were also proposed;the Classical-map hypernetted-chain method, the BBGKY hierarchy. In the late 1970s classical DFT was applied to the liquid–vapor interface and the calculation of surface tension. Other applications followed: the freezing of simple fluids, formation of the glass phase, the crystal–melt interface and dislocation in crystals, properties of polymer systems, and liquid crystal ordering. Classical DFT was applied to colloid dispersions, which were discovered to be good models for atomic systems. By assuming local chemical equilibrium and using the local chemical potential of the fluid from DFT as the driving force in fluid transport equations, equilibrium DFT is extended to describe non-equilibrium phenomena and fluid dynamics on small scales.

Classical DFT allows the calculation of the equilibrium particle density and prediction of thermodynamic properties and behavior of a many-body system on the basis of model interactions between particles. The spatially dependent density determines the local structure and composition of the material. It is determined as a function that optimizes the thermodynamic potential of the grand canonical ensemble. The grand potential is evaluated as the sum of the ideal-gas term with the contribution from external fields and an excess thermodynamic free energy arising from interparticle interactions. In the simplest approach the excess free-energy term is expanded on a system of uniform density using a functional Taylor expansion. The excess free energy is then a sum of the contributions from s-body interactions with density-dependent effective potentials representing the interactions between s particles. In most calculations the terms in the interactions of three or more particles are neglected (second-order DFT). When the structure of the system to be studied is not well approximated by a low-order perturbation expansion with a uniform phase as the zero-order term, non-perturbative free-energy functionals have also been developed. The minimization of the grand potential functional in arbitrary local density functions for fixed chemical potential, volume and temperature provides self-consistent thermodynamic equilibrium conditions, in particular, for the local chemical potential. The functional is not in general a convex functional of the density; solutions may not be local minima. Limiting to low-order corrections in the local density is a well-known problem, although the results agree (reasonably) well on comparison to experiment.

A variational principle is used to determine the equilibrium density. It can be shown that for constant temperature and volume the correct equilibrium density minimizes the grand potential functional  of the grand canonical ensemble over density functions . In the language of functional differentiation (Mermin theorem):

The Helmholtz free energy functional  is defined as .
The functional derivative in the density function determines the local chemical potential: .
In classical statistical mechanics the partition function is a sum over probability for a given microstate of  classical particles as measured by the Boltzmann factor in the Hamiltonian of the system. The Hamiltonian splits into kinetic and potential energy, which includes interactions between particles, as well as external potentials. The partition function of the grand canonical ensemble defines the grand potential. A correlation function is introduced to describe the effective interaction between particles.

The s-body density distribution function is defined as the statistical ensemble average  of particle positions. It measures the probability to find s particles at points in space :

From the definition of the grand potential, the functional derivative with respect to the local chemical potential is the density; higher-order density correlations for two, three, four or more particles are found from higher-order derivatives:

The radial distribution function with s = 2 measures the change in the density at a given point for a change of the local chemical interaction at a distant point.

In a fluid the free energy is a sum of the ideal free energy and the excess free-energy contribution  from interactions between particles. In the grand ensemble the functional derivatives in the density yield the direct correlation functions :

The one-body direct correlation function plays the role of an effective mean field. The functional derivative in density of the one-body direct correlation results in the direct correlation function between two particles . The direct correlation function is the correlation contribution to the change of local chemical potential at a point  for a density change at  and is related to the work of creating density changes at different positions. In dilute gases the direct correlation function is simply the pair-wise interaction between particles (Debye–Huckel equation). The Ornstein–Zernike equation between the pair and the direct correlation functions is derived from the equation

Various assumptions and approximations adapted to the system under study lead to expressions for the free energy. Correlation functions are used to calculate the free-energy functional as an expansion on a known reference system. If the non-uniform fluid can be described by a density distribution that is not far from uniform density a functional Taylor expansion of the free energy in density increments leads to an expression for the thermodynamic potential using known correlation functions of the uniform system. In the square gradient approximation a strong non-uniform density contributes a term in the gradient of the density. In a perturbation theory approach the direct correlation function is given by the sum of the direct correlation in a known system such as hard spheres and a term in a weak interaction such as the long range London dispersion force. In a local density approximation the local excess free energy is calculated from the effective interactions with particles distributed at uniform density of the fluid in a cell surrounding a particle. Other improvements have been suggested such as the weighted density approximation for a direct correlation function of a uniform system which distributes the neighboring particles with an effective weighted density calculated from a self-consistent condition on the direct correlation function.

The variational Mermin principle leads to an equation for the equilibrium density and system properties are calculated from the solution for the density. The equation is a non-linear integro-differential equation and finding a solution is not trivial, requiring numerical methods, except for the simplest models. Classical DFT is supported by standard software packages, and specific software is currently under development. Assumptions can be made to propose trial functions as solutions, and the free energy is expressed in the trial functions and optimized with respect to parameters of the trial functions. Examples are a localized Gaussian function centered on crystal lattice points for the density in a solid, the hyperbolic function  for interfacial density profiles.

Classical DFT has found many applications, for example:
 developing new functional materials in materials science, in particular nanotechnology;
 studying the properties of fluids at surfaces and the phenomena of wetting and adsorption;
 understanding life processes in biotechnology;
 improving filtration methods for gases and fluids in chemical engineering;
 fighting pollution of water and air in environmental science;
 generating new procedures in microfluidics and nanofluidics.

The extension of classical DFT towards nonequilibrium systems is known as dynamical density functional theory (DDFT). DDFT allows to describe the time evolution of the one-body density  of a colloidal system, which is governed by the equation

with the mobility  and the free energy . DDFT can be derived from the microscopic equations of motion for a colloidal system (Langevin equations or Smoluchowski equation) based on the adiabatic approximation, which corresponds to the assumption that the two-body distribution in a nonequilibrium system is identical to that in an equilibrium system with the same one-body density. For a system of noninteracting particles, DDFT reduces to the standard diffusion equation.

See also

 Basis set (chemistry)
 Dynamical mean field theory
 Gas in a box
 Harris functional
 Helium atom
 Kohn–Sham equations
 Local density approximation
 Molecule
 Molecular design software
 Molecular modelling
 Quantum chemistry
 Thomas–Fermi model
 Time-dependent density functional theory
 Car–Parrinello molecular dynamics

Lists
 List of quantum chemistry and solid state physics software
 List of software for molecular mechanics modeling

References

Sources

External links
 Walter Kohn, Nobel Laureate – Video interview with Walter on his work developing density functional theory by the Vega Science Trust

 Walter Kohn, Nobel Lecture

 Electron Density Functional Theory – Lecture Notes
 Density Functional Theory through Legendre Transformation pdf

 Modeling Materials Continuum, Atomistic and Multiscale Techniques, Book
 NIST Jarvis-DFT

Electronic structure methods

Density functional theory


In architecture, the apse (from Latin apsis: "arch, vault") is a semicircular recess covered with a hemispherical vault or semi-dome. It is similar to another form known as an exedra. In Romanesque, Byzantine and Gothic Christian abbey, cathedral and church architecture, the term is applied to a semi-circular or polygonal termination of the main building. This is usually at the liturgical east end (where the altar is). It is also regardless of the shape of the roof, which may be flat, sloping, domed, or hemispherical.

References

Architectural elements

Apse


The Daihatsu Midget is a single-seat mini-truck made bi Japanese automaker Daihatsu. Several distinct vehicles haes borne the Midget name ower the years, but aw hae haed in common a single-seat utilitarian design, wi an enclosed or semi-enclosed cab.

Midget I

The oreeginal Midget featurt a single seat, a doorless cab, an handlebar steering. In 1957 the DK Midget wis introduced. The ingine wis an air-cooled 2-stroke design o 250 cc whilk produced 10 hp.

In 1959 the MP Midget wis introduced - updatit wi siclike features as a steering wheel, doors, an seatin for twa. The ingine wis an air-cooled 2-stroke design o 305 cc which produced 12 hp.

Subsequent revisions tae the MP design wis made, resultin in the model MP4 (whilk featurt a lairger cargo bed than the oreeginal model) an hinderly the MP5 (which introduced automatic ile mixin for the 2 stroke ingine) whilk remained in production til 1972.

Bi 1972, 336,534 units haed been produced, an production wis terminated acause o the faw in popularity o three wheeled models tae mair modren fower wheel models.

The Midget I haes forby been selt ootwi Japan as the "Bajaj", "Tri-Mobile", or "Bemo". It is ane o the first caurs manufactured bi the Japanese automaker Daihatsu, kent for its laich-cost, practical vehicles. Awmaist exclusively uised as an autorickshaw (or 'tuk-tuk'), the Midget wis a weel-kent icon o public transportation in Sooth Asie. Nae meant for performance, this obscure vehicle daes weave throu lairger traffeck weel, in maugre o the fact that it anerlie haes three wheels. Thir oreeginal tuk-tuks ar a bit harder tae fin in modren times.

In Thailand, the Midget MP4 is still in production as an Chinnaraje Midget in Chiang Mai an as an TukTuk Midget MP4 in Bangkok. The facelifted version, kent as MP5 is an aa still manufactured bi the TukTuk (Thailand) Co., Ltd. in Bangkok.

Midget II

Frae 1996 tae 2001, Daihatsu manufactured a fower wheel kei Midget wi fower-wheel drive or air conditionin as options. As Kei caurs, thay wur plenisht wi 660 cc engines.

The Midget II () wis introduced as a concept at the 1993 Tokyo Motor Show. Thare 2 teep o engines available, differentiate bi the injection type, ane bein electronic. Baith ar identical in width an heicht, but the EFI (Electronic Fuel Injection) version is shorter bi 75mm. Thay ar available in ane-seater or 2-seater, wi automatic an manual transmissions available.

External links

 Model of an original Midget
 Toyota Museum page with photo of Midget MP5
 Midget IIs for sale in Japan

Midget
Kei caurs
Three-wheeled motor vehicles
Rear mid-ingine, rear-wheel drive vehicles
First automobile made bi manufacturer

Daihatsu Midget


Tamsui (Chinese: 淡水鎮, Taiwanese: Tām-súi/Tām-chúi, Tongyong Pinyin: Danshuei, Hanyu Pinyin: Danshui) is a sea-side town in Taipei County, Taiwan. The town has a population of 130,105 people. It is named after a river whose name means "Freshwater". The town is also popular as a site for viewing the sun setting into the Taiwan Strait. There are three universities in this small town.

Settlements in Taiwan

Tamsui


A cabal is a group of people who try to control things in a secret way. Cabals are often an important part of a conspiracy theory.

Sometimes people say "There Is No Cabal", or use the abbreviation TINC to mean "There Is No Cabal". The joke is that since a cabal is necessarily secret, only those who are in the cabal can know.

Politics

The former chief of staff, Lawrence Wilkerson, of the Secretary of State Colin Powell said that the foreign policy of George W. Bush's administration were run by a "Cheney-Rumsfeld cabal". With this word he meant that the President had not really the power that he is given by the constitution and that the Vice President and the Secretary of Defense had more influence than they should have.

References

Forms of government

Cabal


Hügelkultur (), literally mound bed  or mound culture is a horticultural technique where a mound constructed from decaying wood debris and other compostable biomass plant materials is later (or immediately) planted as a raised bed. Adopted by permaculture advocates, it is suggested the technique helps to improve soil fertility, water retention, and soil warming, thus benefitting plants grown on or near such mounds.

History

Hügelkultur is a German word meaning mound culture or hill culture. Though the technique is alleged to have been practiced in German and Eastern European societies for hundreds of years, the term was first published in a 1962 German gardening booklet by Herrman Andrä. Inspired by the diversity of plants growing in a pile of woody debris in his grandmother's garden, Andrä promoted "mound culture" as opposed to "flatland culture". This was also posited as an easy way to utilise woody debris without burning, which was illegal. Andrä appears to have been influenced by Rudolf Steiner's biodynamic agriculture. Steiner explained his biodynamic philosophy as developed through meditation and clairvoyance, rejecting scientific inquiry on the grounds that his methods were "true and correct unto themselves." Andrä quotes a 1924 lecture on biodynamics by Steiner, which describes mixing of soil with composting or decaying material in earthen hillocks. Joined by author Hans Beba, another German gardener, "Hill Culture - the horticultural method of the future" was revised and republished several times in the 1970s and 1980s.

The technique was later adopted and developed by Sepp Holzer, an Austrian permaculture advocate. More recent permaculture advocates such as Paul Wheaton strongly promote Hügelkultur beds as a perfect permaculture design.

Use

Construction

In its basic form, mounds are constructed by piling logs, branches, plant waste, compost and additional soil directly on the ground. The pile has the form of a pyramid. The sides of the two slopes both have a grade of between 65 and 80 degrees. The beds are usually about  in area and about  high. However, this height reduces as decomposition progresses.

When positioned on sloped terrain, the beds need to be placed on contour, or put at an angle to the hillside (rather than having them parallel to it). This makes sure the beds do not receive unequal amounts of water. In most cases, it is useful to have the beds positioned against the prevailing wind direction.

The raised bed can form light-duty swales, circles and mazes. Mounds may also be made from alternating layers of wood, sod, compost, straw, and soil. Although their construction is straightforward, planning is necessary to prevent steep slopes that would result in erosion.

In his book Desert or Paradise: Restoring Endangered Landscapes Using Water Management, Including Lake and Pond Construction, Holzer describes a method of constructing Hügelkultur which incorporates rubbish such as cardboard, clothes and kitchen waste. He recommends building mounds that are  wide and any length. Mounds are built in a  trench in sandy soil, and without a trench if the ground is wet.

Planting
The mound is left to rest for several months before planting, although some advise immediate planting.

Anything can be grown on the raised beds, but if the bed will decompose/release its nutrients quickly (so long as it is not made of bulky materials like tree trunks), more demanding crops such as pumpkins, zucchini, cucumbers, cabbages, tomatoes, sweet corn, celery, or potatoes are grown in the first year, after which the bed is used for less demanding crops like beans, peas, and strawberries.

Lifespan
The original German publications described the mounds as having a lifespan of 5–6 years, after which they had to be rebuilt from scratch.

Evidence
As of 2017 there are no peer-reviewed scientific studies available regarding the efficacy of the technique. A few university student projects investigate Hügelkultur but have not been published in scientific journals.

One small scale and short term student project investigated the Hügelkultur method as a potential use for yard trimmings waste, and also if lima beans, kale and okra planted on a Hügelkultur mound showed any signs of nutrient deficiency compared to a non-raised control bed. It was found that over 11 tons of yard trimmings were used in the mound, and no evidence of macronutrient deficiency could be detected in the crops in the short term. Indeed, despite concerns that incorporation of large quantities of high carbon woody matter would lead to nitrogen immobilization and hence nitrogen deficiency in the crop, a higher level of nitrogen was found in the raised bed. However, the micronutrient iron was lower relative to the control bed. The author speculated that no nitrogen deficiency occurred since the roots of the plants did not penetrate past the superficial layers of the mound into the deeper wood-containing region.

A student thesis investigated the water holding capacity of Hügelkultur beds and whether the technique could be useful to prevent karst rocky desertification in China. Over 3 months of measurements, water concentration in hügel mounds remained high. Samples from hügel sites contained almost twice as much water as those from flat control plots. It was suggested that  of hügels has 3-10 times more water than a flat plot affected by karst rocky desertification.

Theory
Many publications and websites advocate the technique based on personal experience of the authors. Some have criticised the technique as lacking genuine scientific principles, and running counter to the ecological principles of soil building with litterfall.

Hügelkultur is said to replicate the natural process of decomposition that occurs on forest floors, however in natural ecosystems wood would be present at the soil surface. Trees that fall in a forest often become nurse logs decaying and providing ecological facilitation to seedlings. As the wood decays, its porosity increases, allowing it to store water like a sponge. The water is slowly released back into the environment, benefiting nearby plants.

These beds are also considered beneficial because of the airpockets created by the settling caused by the wood's decomposition. This gives the benefits of tilling, without the destruction of soil microorganisms that come with tilling ("every time you till the soil, you lose 30% of the organic material (microbial soil life is killed, and plants feast on their bodies)"). And, the organic material of the rotting wood also houses beneficial soil microorganisms.

Hügelkultur beds are said to be ideal for areas where the underlying soil is of poor quality or compacted. They tend to be easier to maintain due to their relative height above the ground.

The decomposition speed of organic material depends on the carbon to nitrogen ratio of the material, among other factors. Wood breaks down relatively slowly because it has one of the highest carbon to nitrogen ratios of all organic matter that is used in composting. If the wood is not processed into smaller pieces with larger surface area to speed up chemical reactions, breakdown is even slower. The decomposition process may, in the short term, take more nitrogen from the soil through microbial activity (nitrogen immobilization), if not enough nitrogen is available. Thus, in the short term, the fertility of the soil may be decreased before, eventually, perhaps after one to two years, the nitrogen level is increased past the original level. Traditionally, therefore, it is said to be advantageous to balance "browns" (e.g. woodchippings) with "greens" (e.g. grass clippings) for efficient composting, and to allow compost to become well-rotted before applying it to a bed, to prevent competition between soil bacteria and plants for nitrogen, which reduces yield.

Criticisms and controversy

Hügelkultur mounds as solid earthworks

Although Hügelkultur beds can safely retain water in light-duty applications (for example, conserving the moisture of rain that falls on the bed), creating heavy-duty rainwater retention areas behind Hügelkultur beds on contour, to catch surface runoff from surrounding areas, can be dangerous. Some designers conflate the Hügelkultur bed's appearance with that of solid earthworks, but Hügelkultur beds cannot predictably control large amounts of stormwater in the way that solid earthworks can. Whereas embankment dams or the hillsides of swales can be relied on to hold back many thousands of gallons of water for weeks to allow it to seep into the ground, and berms can slow runoff, Hügelkultur beds are different in two ways: earthworks have no buoyant core (whereas Hügelkultur mounds contain logs), and the soil that they are made of is compacted. If fresh or dried timber is used in the bed, it may become buoyant in the water-saturated substrate, bursting from the soil covering and releasing all the sitting water through a breach. This can be an issue for years, until the wood is sufficiently rotten and infused with water. Another consideration is that Hügelkultur beds will degrade, shrinking over time into much lower mounds of soft, rich soil. This means that the retention area will have less depth as time goes on, but it also means that the uncompacted soil will remain a threat to breaching even if the logs become saturated.

Some permaculturists have taken mild positions against the "hügel swales" still being promoted by other permaculturists, citing the danger and cross-purposes of Hügelkultur beds and swales. Swales are for long-term installations where perennials - like fruit trees - are grown. Hügelkultur is used for shorter term, more annual crops, as the soil settling that occurs with hugel decomposition is bad for the root system of fruit trees.

There is a recorded instance of a breach occurring in a new project. Upon the first rainstorm, the retention areas behind the Hügelkultur beds filled with water and broke through. The released water carried the freshly-buried logs and dirt downhill, smashing a hole in a building being used as a church and filling the space with mud. No injuries were reported.

Overfertilization, contamination of soil and water habitats
Over-fertilized plants are said to have less flavor, and too much nitrogen can be consumed by eating certain plants which have been over-fertilised (e.g., spinach). Advocates state that overfertilization is a risk in the first year if woodchips are used, which will break down too fast. Instead raised beds made with whole logs release nutrients slowly over a period of years. It has been suggested that excessive use of decomposing organic matter in Hügelkultur could leach out and contaminate and disrupt soil and water habitats.

See also

 Hotbed
 Hot container composting
 Vertical farming

References

External links

Practical step by step guide to implement hügelkultur raised beds
hugelkultur: the ultimate raised garden beds
7 Things to Know About Hugelkultur Gardening
Hugelkultur: Composting Whole Trees With Ease

Composting
Horticultural techniques
Organic gardening
Soil improvers
Waste management
Environmental engineering
Landforms
Landscape
Sustainable gardening
Sustainable design
Water

Hügelkultur


Independence Day (, ), observed annually on 5 July, is a National Holiday in Algeria commemorating colonial Algerian independence from France on 5 July 1962.

Algerian War (1954–1962)

The Algerian War of Independence began in November 1954 and ended in 1962. The war was very brutal and long, and was the most recent major turning point in Algeria's history. Although often fratricidal, it ultimately united Algerians and raised the value of independence and the philosophy of anticolonialism into the national consciousness. Abusive tactics of the French Army remains a controversial subject in France to this day.

In the early morning hours (12:00 am) of 1 November 1954, the National Liberation Army (L'armée de Libération Nationale—ALN) launched attacks throughout Algeria in the opening salvo of a war of independence. An important watershed in this war was the massacre of civilians by the FLN near the town of Philippeville in August 1955. The government claimed it killed 1,273 guerrillas in retaliation; according to the FLN, 12,000 Muslims perished in an orgy of bloodletting by the armed forces and police, as well as colon gangs. After Philippeville, all-out war began in Algeria. The FLN fought largely using guerrilla and terrorist tactics whilst the French counter-insurgency tactics often included severe reprisals and repression.

Eventually, protracted negotiations led to a cease-fire signed by France and the FLN on March 18, 1962, at Evian, France. The Evian accords also provided for continuing economic, financial, technical, and cultural relations, along with interim administrative arrangements until a referendum on self-determination could be held. The Evian accords guaranteed the religious and property rights of French settlers, but the perception that they would not be respected led to the exodus of one million pieds-noirs and harkis.

Between 350.000 and 1 million Algerians are estimated to have died during the war, and more than 2 million, out of a total Muslim population of 9 or 10 million, were made into refugees or forcibly relocated into government-controlled camps. Much of the countryside and agriculture was devastated, along with the modern economy, which had been dominated by urban European settlers (the pied-noirs). French sources estimated that at least 70,000 Muslim civilians were killed or abducted and presumed killed, by the FLN during the Algerian War. Nearly one million people of mostly French, Spanish and Italian descent were forced to flee Algeria at independence due to the unbridgeable rifts opened by the civil war and threats from units of the victorious FLN. Along with them fled most Algerians of Jewish descent and those Muslim Algerians who had supported a French Algeria (harkis). 30–150,000 pro-French Muslims were also killed in Algeria by FLN in post-war reprisals.

French President Charles De Gaulle pronounced Algeria an independent country on 3 July. The decision was published in the official journal the following day, and Algerian leaders declared 5 July, the anniversary of the French arrival in Algiers, to be Independence Day.

See also
 Public holidays in Algeria

References

External links

The Colonial System and Algerian Nationalism

Public holidays in Algeria
July observances
Algeria
Algerian War
Algerian nationalism

Independence Day (Algeria)


Harry Sullivan is a fictional character from the British science-fiction television series Doctor Who. He was a companion of the Fourth Doctor. Harry Sullivan was played by Ian Marter, the character appears as a regular during the programme's twelfth season in 1974–1975.

Character history
Harry is a doctor in the Royal Navy, who is also a medical officer to the United Nations Intelligence Taskforce, the military organisation to which the Doctor works for as a scientific advisor. He is first mentioned (though not seen) in Planet of the Spiders, when the Brigadier thinks the Third Doctor has gone into a coma. The Brigadier calls "Doctor Sullivan" and asks him to come to the Doctor's laboratory, but tells him not to bother when Sergeant Benton wakes the Doctor by offering him a cup of coffee. In the next serial, Robot, after the Doctor's third regeneration, Sullivan is called in to help him, and ends up travelling aboard the TARDIS with the Fourth Doctor and Sarah-Jane Smith (played by Elisabeth Sladen) for several adventures.

The character was originally devised by the production team to do any action scenes required in episodes when they had envisioned that the new Doctor would be played by an older actor (Sarah-Jane even jokingly compares Harry to James Bond at one point). When forty year-old Tom Baker was cast, however, this was no longer a concern and the decision was taken to write Harry out — something producer Philip Hinchcliffe later admitted was probably a mistake, as Harry was a likeable and popular character who worked well with both of his fellow leads.

Harry's last regular appearance is in the season thirteen opener Terror of the Zygons, which had actually been made at the conclusion of the twelfth production block and held over to start the following season. At the conclusion of this story he chooses to return to London by train rather than by TARDIS with the Doctor and Sarah-Jane, who continue their adventures without him. He does, however, reappear three stories later in The Android Invasion, both as the original Harry and an android double. This is the character's final appearance in the programme.

A photo of Harry can be seen in Sarah-Jane Smith's attic in The Sarah-Jane Adventures and in "Invasion of the Bane", Sarah-Jane thought of naming her newly adopted son after him before deciding on Luke.

Television

Season 12

 Robot
 The Ark in Space
 The Sontaran Experiment
 Genesis of the Daleks
 Revenge of the Cybermen

Season 13

 Terror of the Zygons
 The Android Invasion

Novels

 The Companions of Doctor Who
 Harry Sullivan's War by Ian Marter

Virgin New Adventures

 Blood Heat by Jim Mortimore (parallel universe version of Harry)
 Damaged Goods by Russell T. Davies

Virgin Missing Adventures

 System Shock by Justin Richards
 A Device of Death by Christopher Bulis

Past Doctor Adventures

 The Face of the Enemy by David A. McIntee
 Millennium Shock by Justin Richards
 Wolfsbane by Jacqueline Rayner

Short stories

 "The Man From DOCTO(R)" by Andrew Collins (Short Trips: Companions)
 "To Kill a Nandi Bear" by Paul Williams (Short Trips: Past Tense)
 "UNIT Christmas Parties: Ships That Pass" by Karen Dunn (Short Trips: A Christmas Treasury)
 "Suitors, Inc." by Paul Magrs (Short Trips: Seven Deadly Sins)
 "The Last Broadcast" by Matthew Griffiths (Short Trips: A Day in the Life)
 "Mutiny" by Robert Dick (Short Trips: Defining Patterns)

Comics

 "The Psychic Jungle" by Paul Crompton (Doctor Who Annual 1976)
 "Neuronic Nightmare" by Paul Crompton (Doctor Who Annual 1976)
 "The Body Snatcher" by Paul Crompton (Doctor Who Annual 1977)
 "Menace on Metalupiter" by Paul Crompton (Doctor Who Annual 1977)
 "Black Destiny" by Gary Russell, Martin Geraghty and Bambos Georgiou (Doctor Who Magazine 235–237)

Other websites
 Harry Sullivan at The TARDIS Index File website
 Harry Sullivan on the BBC's Doctor Who website

Doctor Who characters

Harry Sullivan (Doctor Who)


Painful sexual act is a medical problem where a person feels pain in their genitals before, during, or after a sexual act.  Doctors call this problem dyspareunia. It can have physical or emotional causes.  Both men and women can have dyspareunia.  Up to one-fifth of women (one in every five) may have dyspareunia at some point in their lives.

Symptoms in women
When a woman experiences a painful sexual act, the pain may distract her from feeling pleasure and excitement.  Her vagina will be less lubricated (wet) and will not expand (dilate) as much as usual.  When the vagina is dry and undilated, thrusting of the penis is painful. Even after the original cause of her pain has disappeared, a woman may feel pain simply because she expects pain.

Causes in women
In most cases, painful sexual acts have a physical cause at first.  There are many physical problems that can cause or worsen painful sexual act. A doctor may be able to identify the cause by doing a careful physical examination and medical history. Some of the most common physical causes are infections of the vagina, urinary tract, cervix, or fallopian tubes; endometriosis; scar tissue left by surgery (like an episiotomy); and ovarian cysts and tumors. Common infections are mycoses (infections caused by a fungus), candidiasis, chlamydia, trichomoniasis, urinary tract infections, coliform bacteria, monilial organisms and herpes). Painful sexual act can also be caused by problems with a woman's anatomy, like hymenal remnants (pieces of the hymen that stay in the vagina) or female genital mutilation, or when the entrance to the vagina has become too small for normal penetration (Sarrell and Sarrell 1989).

In women who are past menopause, a common cause of painful sexual act is having too little estrogen.  In women who are breastfeeding, a common cause is dryness of the vagina. Women who are getting radiation therapy for cancer in the pelvic area may have pain during sex because the walls of the vagina have atrophied (wasted away) and are more sensitive to injury.  Dryness in the vagina can also be a cause of painful sexual act for women with Sjögren's syndrome, which attacks the glands that create saliva and tears.

Painful sexual act may be one of the first symptoms of cystitis (a bladder infection). People with cystitis may have bladder pain during or after sex.  Women with cystitis usually have pain the day after sex, because the muscles around her bladder are spasming (tightening up painfully). Women with cystitis usually also have urinary frequency (needing to urinate a lot) and/or urinary urgency (needing to urinate suddenly).

In men
There are a number of physical factors as well. Pain is sometimes experienced in the testicular or glans area of the penis immediately after ejaculation. Infections of the prostate, bladder, or seminal vesicles can lead to burning or itching sensations following ejaculation. Men suffering from cystitis may experience intense pain at the moment of ejaculation and is focused at the tip of the penis. Gonorrheal infections are associated with burning or sharp penis pains during ejaculation. Urethritis or prostatitis can make genital stimulation painful or uncomfortable. Anatomic deformities of the penis (retraction of a too-tight foreskin) may also result in pain during sexual act.

In men pain in the genital organs during ejaculation or immediately thereafter is experienced as sharp, stabbing, and/or burning, it may be persistent and returning. The duration of pain is usually brief. The immediate cause of psychogenic post ejaculatory pain is the involuntary painful spasm or cramping of certain pain-sensitive muscles in the male genital and reproductive organs, the painful muscle cramps may be attributable to a man's conflict about ejaculating.

A pelvic floor disorder can also be the cause of pain during and after sex.

Diagnosis
Sufferers will see several doctors before a correct diagnosis is made. Sufferers are also often hesitant to seek treatment for chronic vulvar pain, especially since many women begin experiencing symptoms around the same time they become sexually active. Before being successfully diagnosed patients sometimes are told that the pain is "in their head". For the diagnosis doctor carefully takes a history and carefully examines the pelvis to duplicate the discomfort and to identify a site or source of the pelvic pain. The diagnosis of painful sexual act has to be differentiated from conditions known as '''chronic vulvar pain''' and vaginismus. It is worth to be sure whether the painful sexual act is acquired or lifelong and whether it is generalized (complete) or situational. During the first two weeks, painful sexual act caused by penis insertion or movement of the penis in the vagina or by deep penetration is often due to disease or injury deep within the pelvis. Inquiry should determine whether the pain is superficial or deep - whether it occurs primarily at the vaginal outlet or vaginal barrel or upon deep thrusting against the cervix. The possible role of psychological factors in either causing or maintaining the pain must be acknowledged.

Atrophy of vagina as a source of painful sexual act is most frequently seen in women after menopause and is generally associated with estrogen deficiency. The latter  is associated with inadequacy of lubrication of vagina, which can lead to painful friction during sexual act.

Treatment
Doctor explains to the patient what has happened; including identifies the sites and causes of pain. He makes clear that the pain will, in almost all cases, disappear over the time or at least will be greatly reduced. If there is a partner, doctor explains him also the causes and treatment and encourages him to be supportive. Doctor removes the source of pain when needed. He encourages the patient to learn about her body, to explore her own anatomy and learn how she likes to be caressed and touched. Doctor  encourages the couple to add pleasant, sexually exciting experiences to their regular interactions, such as bathing together (in which the primary goal is not cleanliness), mutual caressing without sexual act, and using sexual books, pictures, and videos. In couples where a woman is preparing to receive vagina act, such activities tend to increase both lubrication of vagina and its dilation, both of which decrease friction and pain. Prior to sexual act, oral sex may also prove very useful to relax and lubricate the vagina (providing both partners are comfortable with it). Doctor prescribes very large amounts of water-soluble lubricant during sexual act. He discourages petroleum jelly. Moisturizing skin lotion may be recommended as an alternative lubricant, unless the patient is using a condom or other latex product. Lubricant should be liberally applied (two tablespoons full) to both the penis and the orifice of the vagina. A folded bath towel under the receiving partner's hips helps prevent spillage on bedclothes. Doctor instructs the receiving partner to take the penis of the penetrating partner in their hand and control insertion themselves, rather than letting the penetrating partner do it.
 For those who have pain on deep penetration because of pelvic injury or disease, doctor recommends a change in sex positions to one admitting less penetration. In women receiving vaginal penetration maximum vaginal penetration is achieved when the receiving woman lies on her back with her pelvis rolled up off the bed, compressing her thighs tightly against her chest with her calves over the penetrating partner's shoulders. Minimal penetration occurs when a receiving woman lies on her back with her legs extended flat on the bed and close together while her partner's legs straddle hers.
 A manual physical therapy  treating pelvis and vagina sticking together may decrease or eliminate pain during sexual act.

Related conditions
 Vaginismus
 Endometriosis

References

Other websites
 Sandra Risa Leiblum, Ph.D. sexual act/ Sexual Pain Disorders - Painful sexual act
 WhenSexHurts - a support community for couples struggling with intimacy due to disability

Sexual acts

Painful sexual act


A Panzerfaust is a recoilless rifle that was invented by Germany. A Panzerfaust can only be used once unlike the Panzerschreck or the Bazooka. The Panzerfaust was used heavily late in World War II, especially during the Battle of Berlin. They were made in very large numbers. They were less powerful than later Rocket-propelled grenades.

Nazi Germany
Rifles

Panzerfaust


A Christian liturgy is a set of steps or rituals done by Christians as a form of worship, done by Christian denomination. The liturgy or form of worship has changed over time, and different groups also have different prescriptions on how such a celebration should be done. The worship on a Sunday might be different from that which is done on Easter.

Anglican, Orthodox, Lutheran, or other groups, when using the words "the liturgy", normally mean a standardized order of events observed during a religious service, often including the Eucharist or Communion. Liturgy may mean an elaborate formal ceremony such as the Catholic Mass. The open or waiting worship of Quakers is an example of a non-liturgical service because there is no structured order of events.

Liturgical churches are those that use a well-defined liturgy, in which many of the words and music used follow basic patterns each time the service is conducted. The liturgy may date to the second century or earlier. Most Orthodox, Catholic, Anglican, and Lutheran churches are liturgical, most other churches to a far lesser extent. Non-liturgical churches usually follow a common worship sequence from one service to the next, with several elements common to many such services. These elements often include readings from the Bible, hymns, a sermon, offerings of money, and at certain times, Communion.

Notes

Related pages
Christian calendar

References
Bowker, John, ed. (1997) Oxford Dictionary of World Religions. Oxford University Press. .
"What Do Quakers Believe?". Quaker Information Center, Philadelphia, PA, 2004.

Liturgy

Christian liturgy


40 (also written as forty or four ten) is the number that is after thirty-nine and before forty-one.

The prime factors of forty are 2 and 5. (2 * 2 * 2 * 5 = 40)

Forty is also the only number in the English language which is spelt in alphabetical order.

The Bible
In the Judeo-Christian Bible, the number forty has special meaning. The Jews wandered in a desert for forty years, there was a forty-day and forty-night rainstorm, and other instances.

Integers

40 (number)


Doodlakine is a town  east of Perth, Western Australia. It is within the Shire of Kellerberrin along the Great Eastern Highway. The town has a crossing loop for trains on the Perth-to-Kalgoorlie railway and serves as a stop on the MerredinLink rural train service.

History
The area was first visited by Europeans in 1864 when explorers came and charted the area. The word Doodlakine is Aboriginal word for a particular rock formation north of the townsite.

An area close to the townsite, along the road to the Yilgarn goldfields and near a reliable water supply, was set aside in 1891 for a town to be established. This was gazetted as the Doodlakine townsite in the same year. Later a railway line was constructed through the area about  south of the town, and the government soon subdivided area along the line. This area was gazetted as a second part of the townsite in 1899.

In 1932 the Wheat Pool of Western Australia announced that the town would have two grain elevators, each fitted with an engine, installed at the railway siding.

The town overflows with people each year during a music concert held at the pub. Hundreds of people come from around the state and camp behind the pub.

Doodlakine is affectionately known by the locals as "Doodlie".

Economy
The surrounding areas produce wheat and other cereal crops. The town is a receival site for Cooperative Bulk Handling.

Rail services
Transwa's MerredinLink and Prospector services stop at Doodlakine, at least one service each day.

References

External links

Towns in Western Australia
Wheatbelt (Western Australia)
Grain receival points of Western Australia

Doodlakine, Western Australia


When the Dutch and Swedes established colonies in the Delaware Valley of what is now Pennsylvania, in North America, they quickly imported enslaved Africans for labor; the Dutch also transported them south from their colony of New Netherland. Enslavement was documented in this area as early as 1639. William Penn and the colonists who settled in Pennsylvania tolerated slavery. Still, the English Quakers and later German immigrants were among the first to speak out against it. Many colonial Methodists and Baptists also opposed it on religious grounds. During the Great Awakening of the late 18th century, their preachers urged slaveholders to free people their slaves. High British tariffs in the 18th century discouraged the importation of additional slaves, and encouraged the use of white indentured servants and free labor.

During the American Revolutionary War, Pennsylvania passed the Gradual Abolition Act (1780), the first such law in the new United States. Pennsylvania law freed those children born to enslaved mothers after that date. They had to serve lengthy indentured servitude until age 28 before becoming free as adults. Emancipation proceeded, and by 1810, fewer than 1,000 captives were in the Commonwealth. None appeared in records after 1847.

British colony
After the founding of Pennsylvania in 1682, Philadelphia became the region's main port for the import of slaves. Throughout the colony and state's history, most slaves lived in or near that city. Although most slaves were brought into the colony in small groups, in December 1684, the slave ship Isabella unloaded a cargo of 150 slaves from Africa. Accurate population figures do not exist for the early colonial period, but more demographic data is available after 1750. Estate records from 1682 to 1705 reveal that fewer than 7% of families in Philadelphia owned slaves.

The first recorded formal protest against slavery, the 1688 Germantown Quaker Petition Against Slavery, was signed by German members of a Quaker meeting. Philadelphia Quakers rejected the petition, writing, "We having inspected ye matter, above mentioned, and considered of it, we find it so weighty that we think it not expedient for us to meddle with it here." Some Pennsylvania Quakers remained slaveholders through the first half of the eighteenth century even as individual abolitionist Quakers like Benjamin Lay, John Woolman, and Anthony Benezet questioned the practice. In 1776, the Philadelphia Yearly Meeting forbade members from owning slaves. (See: Quakers in the Abolition Movement)

William Penn, the proprietor of the Province of Pennsylvania, held at least 12 slaves. They took part in the construction of the main house and outbuildings on his estate, Pennsbury. Penn left the colony in 1701, and never returned.

Laws
Until 1700, enslaved people came under the same laws that governed indentured servants. Beginning that year, the colony passed laws to try slaves and free blacks in non-jury courts rather than under the same terms as other residents of the colony.

Under An Act for the Better Regulating of Negroes in this Province (March 5, 1725–1726), numerous provisions restricted slaves and free blacks.
(Section I) if a slave was sentenced to death, the owner would be paid full value for the slave.
(Sec II) Duties on slaves transported from other colonies for a crime are doubled.
(Sec III) If a slave is freed, the owner must have a sureties bond of £30 to indemnify the local government in case he/she becomes incapable of supporting himself.
(Sec IV) A freed slave fit but unwilling to work shall be bound out [as an indentured servant] on a year-to-year basis as the magistrates see fit. And their male children may be bound out until 24 and women children until 21.
(Sec V) Free Negroes and Mulattoes cannot entertain, barter or trade with slaves or bound servants in their homes without leave and consent of their master under penalty of fines and whipping.
(Sec VI) If fines cannot be paid, the freeman can be bound out.
(Sec VII) A minister, pastor, or magistrate who marries a negro to a white is fined £100.
(Sec VIII) If a white cohabits under pretense of being married with a negro, the white will be fined 30 shillings or bound out for seven years, and the white person's children will be bound out until 31. If a free negro marries a white, they become slaves during life. If a free negro commits fornication or adultery with a white, they are bound out for 7 years. The white person shall be punished for fornication or adultery under existing law.
(Sec IX) Slaves tippling or drinking at or near a liquor shop or out after nine, 10 lashes.
(Sec X) If more than 10 miles from their master's home, 10 lashes.
(Sec XI) Masters not allowed to have their slaves to find and or go to work at their own will receive a 20 shilling fine.
(Sec XII) Harboring or concealing a slave: a 30 shillings a day fine.
(Sec XIII) Fine to be used to pay the owners of slaves sentenced to death. This law was repealed in 1780.

During the colonial era, the Pennsylvania General Assembly passed laws that imposed duties on importing enslaved Africans to the colony, beginning in 1700. The officials of the Board of Trade rescinded the duties, which the general assembly subsequently reimposed: 1700: 20 shillings per person, 1750: 40 shillings, 1712: £20, 1715 to 1722 and again in 1725: £5: each time the Board of Trade overturned the laws, they were re-established by the general assembly.

Conditions
In the colony's first years, slaveholders forced slaves to clear land and build housing. Once the colony was established, the slaves took on various jobs. In Philadelphia, where most slaves lived, many were household servants, while others were trained in different trades and as artisans. In 1767, the wealthiest 10% of the population owned 44% of slaves; the poorest 50% of residents owned 5% of slaves. The wealthy used them as domestic servants and expressions of their wealth. Middling merchants enslaved people as servants, using some as apprentices in the business or other jobs also occupied by indentured servants. As Philadelphia was a port city, many slaves worked in jobs associated with shipping. They worked as gangs in rope-walks, and learned sailmaking. Some sailors enslaved people as workers so that the sailors could increase their share of profits, as the slaves would be given none.

In rural areas, slaves generally worked as household servants or farmhands, and sometimes both depending on need, just as farm families took on all jobs. In Southeastern Pennsylvania, iron masters who owned slaves sometimes leased them out locally to work at charcoal manufacture and the surface mining of limestone and iron ore.

Due to a lack of sanitation and understanding of disease transmission, Philadelphia was an unhealthy place during the colonial period, with a death rate of 58 per 1,000. Many slaves were among those who died early. As more males were imported than females at the time, family formation was limited. Without the continued importation of new slaves, the slave population would not have increased.

Resistance and abolition
By the time of the French and Indian War, the number of slaves in the state was at its highest. More had been imported in the mid-18th century, as the improving economy in the British Isles had resulted in fewer immigrants coming as indentured servants. Given continued Anglo-European immigration to the colony, slaves as a percentage of the total population decreased over time. By the time of the American Revolution, slavery had decreased in importance as a labor source in Pennsylvania. The Quakers had long disapproved of the practice on religious grounds, as did Methodists and Baptists, active in the Great Awakening. In addition, the recent wave of German immigrants opposed it based on their religious and political beliefs. The Scots-Irish, also recent immigrants, generally settled in the backcountry on subsistence farms. As a group, they were too poor to buy slaves. In the late colonial period, people found it economically viable to pay for free labor. Another factor against slavery was the rising enthusiasm of revolutionary ideals about human rights

Religious resistance to slavery and the slave-import taxes led the colony to ban slave imports in 1767. Slaveholders among the state's Founding Fathers included Benjamin Franklin, John Dickinson, Robert Morris, Edmund Physick and Samuel Mifflin. Franklin and Dickinson both gradually became supporters of abolition.

In 1780, Pennsylvania passed the first state Abolition Act in the United States under the leadership of George Bryan. It followed Vermont's abolition of slavery in its constitution of 1777. The Pennsylvania law ended slavery through gradual emancipation, saying:
That all Persons, as well Negroes, and Mulattos, as others, who shall be born within this State, from and after the Passing of this Act, shall not be deemed and considered as Servants for Life or Slaves; and that all Servitude for Life or Slavery of Children in Consequence of the Slavery of their Mothers, in the Case of all Children born within this State from and after the passing of this Act as aforesaid, shall be, and hereby is, utterly taken away, extinguished and for ever abolished.

This act repealed the acts of 1700 and 1726 that had established separate courts and laws specific to Negroes. At this point, state law gave slaves the same rights as bound servants. Free Negroes had, in theory, the same rights as free Whites. The law did not free those approximately 6,000 persons already enslaved in Pennsylvania. Children born to enslaved mothers had to serve as indentured servants to their mother's owner until they were 28 years old.  (Such indentures could be sold.)

Pennsylvania became a state with an established African-American community. Black activists understood the importance of writing about freedom, and were essential participants in abolitionist groups. They gained access to papers run by anti-slave supporters and printed articles about freedom. Anti-slavery pamphlets and writings were rare in the South, but widely distributed in the state of Pennsylvania. African-American activists also began to hold meetings around the state, which white rioters sometimes disrupted. The activists continued to hold their meetings. African-American activists also contributed to the operations of the Underground Railroad, and aided formerly enslaved people to freedom in the state. The activists created the Vigilant Association in Philadelphia, which helped refugees from slavery to escape from enslavers and get resettled in free states.

Decline of slavery
In 1780, the abolition act provided for the children of slave mothers to remain in servitude until the age of 28. Section 2 of the Act stated, "Every negro and mulatto child born within this state after the passing of this act as aforesaid who would in case this act had not been made, have been born a servant for years or life or a slave, shall be deemed to be and shall be, by virtue of this act the servant of such a person or his or her assigns who would in such case have been entitled to the service of such child until such child shall attain unto the age of twenty-eight years...". It required that they and children of African-descended indentured servants be registered at birth. Some Quarter Sessions records of Friends Meetings include births of children identified as mulatto or black.

The federal censuses reflect the decline in slavery. In addition to the effects of the state law, many Pennsylvania slaveholders freed their slaves in the first two decades after the Revolution, as did Benjamin Franklin. Revolutionary ideals and continued appeals by Quakers and Methodist clergy for the manumission of slaves inspired them. The first U.S. Census in 1790 recorded 3,737 slaves in Pennsylvania (36% of the Black population). By 1810, the Black population had more than doubled, but the percentage of slaves had dropped to 3%; only 795 slaves were listed in the state.

End of slavery
Slavery was ended in Pennsylvania in 1847 by the state legislature. An Act to Prevent Kidnapping, Preserve the Public Peace, Prohibit the Exercise of Certain Powers Heretofore Exercised by Certain Judges, Justices of the Peace, Aldermen and Jailors in This Commonwealth (1847), did not recognize the property rights of slaveholders, inside or outside the state. "From the Southern point of view the conditions in the state after 1847 were such as to make imperative the passing of a new fugitive slave law to be vigorously enforced by the government of the United States." Much of the 1847 state law was superseded by the federal Fugitive Slave Act of 1850, but by then, all formerly enslaved Pennsylvanians were free.

The following table represents the growth of Pennsylvania's free black population and the decline of its enslaved population.

See also
Indentured servitude in Pennsylvania
Redemptioners
History of Pennsylvania
An Act for the Gradual Abolition of Slavery (1780)
Prigg v. Pennsylvania (1842)
 History of slavery in the United States by state

References

Bibliography

Berlin, Ira. Generations of Captivity: A History of African-American Slaves. (2003)

External links
 "Slavery in Pennsylvania", Slavery in the North website
 "Pennsylvania slavery by the numbers", USHistory.org
 "African Americans in Pennsylvania", President's House Museum Center
Edward Raymond Turner, The Negro in Pennsylvania Slavery-Servitude-Freedom, American Historical Association, 1911

Pennsylvania
African-American history of Pennsylvania
Anti-black racism in Pennsylvania

History of slavery in Pennsylvania


A nucleobase is a part of RNA and DNA which may be involved in pairing (see base pair). Nucleobases are important for genetics.

They include cytosine, guanine, adenine, thymine in (DNA), uracil in (RNA) and xanthine and hypoxanthine (mutated forms of guanine and adenine). These are abbreviated as C, G, A, T, U, X and HX respectively. They are usually simply called bases in genetics. Because A, G, C and T appear in the DNA, these molecules are called DNA-bases; A, G, C and U are called RNA-bases.

Uracil replaces thymine in RNA.

Other websites
Base pairing in DNA Double Helix (shows specific hydrogen bonds)

Organonitrogen compounds
DNA

Nucleobase


Remagen is a town in Germany in Rhineland-Palatinate, in the district of Ahrweiler. It is about a one hour drive from Cologne , just south of Bonn, the former capital of West Germany. It is on the River Rhine. There is a ferry across the Rhine from Remagen every 10–15 minutes in the summer. Remagen has many historic buildings, churches, castles and monuments. Cars are banned from the big pedestrian zone which has plenty of shops.

Overlooking the west bank of the Rhine just north of the city centre is a church called the Apollinariskirche. It has an observation deck that is only open to parishioners on Sundays. Walkers reach the church via a dirt track that passes a series of roadside monuments. One for each of the fourteen Stations of the Cross. The church grounds contain an outdoor crypt and an abbey. Further down the river is one of the many castles along the River Rhine, perched even higher than the Apollinariskirche.

History
The Roman Empire built a border fort at Rigomagus (or Ricomagus), west of the Rhine. This was about 12 miles north of the site of the first bridge ever built across the Rhine (at Neuwied).

The fort was one of several built by Drusus, commander of the Roman army along the Rhine. The gateway still survives and is a popular tourist attraction.

Local legend says that a ship carrying various relics from Milan to Cologne was stopped in the river in 1164, unable to move despite the strong current, until it mysteriously edged in toward the shore. The remains of St Apollinaris were put ashore, and the ship was then able to sail onward. These remains were buried in a chapel which had been part of the Roman fort, which became the basis for a church which bore his name, and was rebuilt several times over the years.

Prisoner enclosures

In 1945 the U.S. built one of the many enclosures on the west bank of the Rhine–the so called Rheinwiesenlager– close to Remagen. The camps were used by the Allies to house captured Germans, often under very poor conditions. Several thousand prisoners are estimated to have died in the various camps, including 1,212 who are now buried in the Bad Bodendorf Cemetery. They were deprived of the legal protection that the Geneva Convention provides prisoners of war by being called Disarmed Enemy Forces. The International Red Cross was not permitted to investigate conditions in the camps.

Sights

Apollinariskirche
The Apollinariskirche was built 1839-1842 on the site of the medieval Martinskirche. The frescos on the inside of the neo-Gothic church were painted by members of the artists group called the "Nazarenes". Three cycles show the life of Jesus, the life of Mary, and the history of Saint Apollinaris, legendary Bishop of Ravenna. In the crypt is a silver bust of the saint, which is raised from the sarcophagus every year at the pilgrimage time at the end of July. From the statue of Saint Francis of Assisi on top of the church, there is a lovely view of Remagen and the romantic Rhine Valley.

Peace Museum "Remagen Bridge"

Remagen Railway Bridge was the first bridge across the Rhine captured in World War II
The museum is housed in the towers of the famous bridge built between 1916 and 1918. It opened in 1980 and tells the story of the bridge and the prison camp, "Golden Mile."

Arp Museum housed in the Bahnhof Rolandseck
The historic railway station at Rolandseck now houses a museum devoted to the work of Hans Arp. The 19th century railway station was transformed into a cultural venue for all the arts. Johannes Brahms, Clara Schumann and Franz Liszt gave concerts there. The young poet Guillaume Apollinaire even fell in love there. The building was almost destroyed after World War II, but in 1964 the Bonn art dealer Johannes Wasmuth brought it back to life. Musicians such as Martha Argerich, Stefan Askenase, and Yehudi Menuhin, artists such as Hans Arp, Oskar Kokoschka and Günther Uecker, and performers such as Marcel Marceau have all appeared there.

Famous People
 Peter Maech, 23rd abbot of Maria Laach (1512–1552)
 Henriette Jügel (born 1778 in Remagen), painter
 Emilie Storck (born 1827 in Remagen), wife of Friedrich Wilhelm Raiffeisen
 Thomas Gottschalk (born 1950), German TV presenter, lives at Schloss Marienfels
 Rudolf Caracciola (born 1901 in Remagen; died 1959 in Kassel), racing driver
 Bernhard Philipp (born 1948 in Remagen), Capuchin, theologian, artist
 Klaus Barth (born  1935 in Remagen), retired ambassador, assistant chairman of the German Nepal Friendship Association
 Jean Lessenich (born 1942 in Remagen), tracer, author
 Baptist Schneider (1867–1946), photographer in Remagen
 Roland Ries (born 1930 in Remagen), prelate, first clerk of the Catholic bureau in Mainz, president of the Deutsche Krankenhausgesellschaft (German hospital association)
 Willi Ockenfels (born in Remagen), missionary in South Africa
 Stefanie Manhillen (born 1973 in Remagen), artist
 Charles Rettinghaus (born 1962 in Remagen), actor and dubbing artist

References

Other websites

Official Website
Remagen University of Applied Sciences
Museum of the Bridge
ETO Air Ace Shot Down by Allied Gunners over Remagen Bridge
The Bridge at Remagen : film by Alan Heath
The Remagen Bridgehead, March 1945
good account of the events

Remagen


The École nationale supérieure des arts et industries textiles (ENSAIT) is a French Engineering grand établissement (grande école) and a member of UP-TEX research cluster (Union Pôle Textile).

ENSAIT is a higher education and research institute, gathering all the disciplines related to textiles. ENSAIT chairs include four departments related to education and research.

Admission

 A majority of full-time students requesting admission have to pass a competitive exam (Concours e3a) in order to attend ENSAIT at the end of their undergraduate studies.
 International students with a bachelor's degree can also request for admission. About fifty percent of students at ENSAIT have an international profile.
 Professional part-time education is also developed.

Textile curricula and research activities

ENSAIT different curricula lead to the following degrees :
 Ingénieur ENSAIT Master's degree
 Masters Research and Specialized Masters, in cooperation with the University of Lille, École centrale de Lille and École nationale supérieure de chimie de Lille.
 Doctoral degree

The major fields of study and research at ENSAIT are:
 Technical textiles, Mechanical engineering
 Industrial and manufacturing engineering
 Smart material
 Textiles Chemistry, Biotechnology in Textiles
 Clothing Technologies, Design

During first year at ENSAIT, students study all the basics of textile technology.
Each year, approximately 80 students receive an ENSAIT Master's degree referred-to as diplôme d'ingénieur ENSAIT, and around 10 students receive a doctoral degree.

History
The school was founded in Roubaix (Nord-Pas de Calais, France) with municipal funding. It was originally meant to provide a special studying program for the requirements of the textile industry at Roubaix and France. After 1889, the institution became known as the École d'Arts et Métiers Textiles.
Because the school was near from the war front, it was closed in some wartime periods (World War I  and World War II), many students and academic staff died in these wars.

Nowadays, the ENSAIT has a very large parc of machinery. In 1991, the GEMTEX was inaugurated as the first French center with research competence in all textile engineering fields. Entrepreneurship is also promoted with GENI-INNOTEX.

Student life
Since the ENSAIT foundation, the students perpetuate their own traditions and folklore, and are members of a student society. They call themselves "AIT" . The "BDE" folklore includes traditional clothing, language, songs and legends, related symbolism, and ceremonials. BDE activities are independent of the administration of the school and are exclusively run by the students, although the two parts often cooperate for organising cultural or sporting events.

International
The ENSAIT has a partnership with more than 300 institutions around the world.

Technical universities and colleges in France
Textile industry of France
Textile schools
Universities and colleges in Lille
Roubaix
Educational institutions established in 1889
1889 establishments in France

ENSAIT