Chemical kinetics experiments can then be carried out in a " pump-probe " fashion using a laser to initiate the reaction ( for example by preparing one of the reagents by photolysis of a precursor ), followed by observation of that same species ( for example by laser-induced fluorescence ) after a known time delay.

The fluorescence signal is captured by a photomultiplier a known distance downstream of the de Laval nozzle.

With a few exceptions related to high-energy photons ( such as fluorescence, harmonic generation, photochemical reactions, the photovoltaic effect for ionizing radiations at far ultraviolet, X-ray, and gamma radiation ), absorbed electromagnetic radiation simply deposits its energy by heating the material.

An early observation of fluorescence was described in 1560 by Bernardino de Sahagún and in 1565 by Nicolás Monardes in the infusion known as lignum nephriticum ( Latin for " kidney wood ").

Another way to define the quantum yield of fluorescence, is by the rate of excited state decay:

Trivalent lanthanides such as terbium and dysprosium are the principal activators of the creamy yellow fluorescence exhibited by the yttrofluorite variety of the mineral fluorite, and contribute to the orange fluorescence of zircon.

* When scanning the fluorescent intensity across a plane one has fluorescence microscopy of tissues, cells, or subcellular structures, which is accomplished by labeling an antibody with a fluorophore and allowing the antibody to find its target antigen within the sample.

* Immunology: An antibody is first prepared by having a fluorescent chemical group attached, and the sites ( e. g., on a microscopic specimen ) where the antibody has bound can be seen, and even quantified, by the fluorescence.

* FLIM ( Fluorescence Lifetime Imaging Microscopy ) can be used to detect certain bio-molecular interactions that manifest themselves by influencing fluorescence lifetimes.

* DNA detection: the compound ethidium bromide, in aqueous solution, has very little fluorescence, as it is quenched by water.

Recovery of the protein crystals requires imaging which can be done by the intrinsic fluorescence of the protein or by using transmission microscopy.

Since any fluorescence image is made up of a large number of such small fluorescent light sources, the image is said to be " convolved by the point spread function ".

In fluorescence microscopy, many wavelengths of light, ranging from the ultraviolet to the visible can be used to cause samples to fluoresce to allow viewing by eye or with the use of specifically sensitive cameras.

In contrast fluorescence in materials is characterized by emission which ceases when the external illumination is removed.

Crookes investigated the properties of cathode rays, showing that they travel in straight lines, cause fluorescence in objects upon which they impinge, and by their impact produce great heat.

Emission can also be induced by other sources of energy such as flames or sparks or electromagnetic radiation in the case of fluorescence.

Cathodoluminescence, the emission of light when atoms excited by high-energy electrons return to their ground state, is analogous to UV-induced fluorescence, and some materials such as zinc sulfide and some fluorescent dyes, exhibit both phenomena.

In 1819 Edward D. Clarke and in 1822 René Juste Haüy described fluorescence in fluorites, Sir David Brewster described the phenomenon for chlorophyll in 1833 and Sir John Herschel did the same for quinine in 1845.

This is an image of a cultured human endothelial cell taken by myself ( David Hackos ) using a fluorescence microscope.

I was puzzled by the remark, then I recalled the voice of mild Professor Howard Griggs three years ago in a university lecture on primitive societies.

This Sunday those attending the second session will hear a lecture by Kern on the world situation ; ;

Two works by Mauss in particular proved to have enduring relevance: Essay on the Gift, a seminal analysis of exchange and reciprocity, and his Huxley lecture on the notion of the person, the first comparative study of notions of person and selfhood cross-culturally.

* Doing with Images Makes Symbols: Communicating with Computers Video lecture by Alan Kay with lots of examples of early graphic user interfaces

* The full text of a lecture by John Melville-Jones on the life of this emperor is located at:.

In a lecture in 2001, Stephen Hawking stated " The reason most scientists don't believe in astrology is because it is not consistent with our theories that have been tested by experiment.

* Apoptosis on-line lecture by Xiaodong Wang

In parallel with the revolutions against rising political absolutism based on established religion and the replacememt of faith by reasonable faith, new systems of metaphysics were promulgated in the lecture halls by charismatic professors, such as Immanuel Kant, Nietzsche and Hegel.

The term " black hole " was first publicly used by John Wheeler during a lecture in 1967.

Here he remained, commissioned by Pope Gregory XIII to lecture on polemical theology in the new Roman College.

* China Rediscovers its Own History 100 minute lecture on Chinese history given by renowned scholar / author Yu Ying-shih, Emeritus Professor of East Asian Studies and History at Princeton University.

The lecture that evening was on " Fairy Life ", and at the end of the meeting Polly Wright showed the two fairy photographs taken by her daughter and niece to the speaker.

*' From Hilbert's Problems to the Future ', lecture by Professor Robin Wilson, Gresham College, 27 February 2008 ( available in text, audio and video formats ).

When Seamus Heaney gave an Oxford lecture on the poet he opened by addressing the assembly, " Dylan Thomas is now as much a case history as a chapter in the history of poetry ", querying how ' Thomas the Poet ' is one of his forgotten attributes.

The global campus online, led by American universities, allows free access to class materials and lecture files recorded during the actual classes.

One of the most important discoveries relating to current was made accidentally by Hans Christian Ørsted in 1820, when, while preparing a lecture, he witnessed the current in a wire disturbing the needle of a magnetic compass.

*" Existentialism is a Humanism ", a lecture given by Jean-Paul Sartre

The Hobbit by J. R. R. Tolkien ( 1937 ) is seminal, predating the lecture On Fairy-Stories by the same author by a few years.

by J. H. Thayer, with other essays, 1889 ), originally a lecture.

His most famous pupil, Arrian, studied under him when a young man ( c. 108 AD ) and claimed to have written the famous Discourses from his lecture notes, though some argue they should be considered an original composition by Arrian, comparable to the Socratic literature.

* The Free Software Movement and the Future of Freedom, a 2006 lecture by Richard Stallman

This was filmed by Americans for exhibition outside the German-speaking world and was presented in special venues, not as a continuous film, but with the separate scenes interspersed with lantern slides, a lecture, and live choral numbers, to increase the running time of the spectacle to about 90 minutes.