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Snub dodecahedron

In geometry, the snub dodecahedron, or snub icosidodecahedron, is an Archimedean solid, one of thirteen convex isogonal nonprismatic solids constructed by two or more types of regular polygon faces.

The snub dodecahedron has 92 faces (the most of the 13 Archimedean solids): 12 are pentagons and the other 80 are equilateral triangles. It also has 150 edges, and 60 vertices.

It has two distinct forms, which are mirror images (or "enantiomorphs") of each other. The union of both forms is a compound of two snub dodecahedra, and the convex hull of both forms is a truncated icosidodecahedron.

Kepler first named it in Latin as dodecahedron simum in 1619 in his Harmonices Mundi. H. S. M. Coxeter, noting it could be derived equally from either the dodecahedron or the icosahedron, called it snub icosidodecahedron, with a vertical extended Schläfli symbol $$s \scriptstyle\begin{Bmatrix} 5 \\ 3 \end{Bmatrix}$$ and flat Schläfli symbol $sr{5,3}.$

Cartesian coordinates
Let $ξ ≈ 0.943$ be the real zero of the cubic polynomial $x^{3} + 2x^{2} − φ^{2}$, where $φ$ is the golden ratio. Let the point $p$ be given by $$p= \begin{pmatrix} \varphi^2-\varphi^2\xi \\ -\varphi^3+\varphi\xi+2\varphi\xi^2 \\ \xi \end{pmatrix}. $$ Let the rotation matrices $M_{1}$ and $M_{2}$ be given by $$ M_1= \begin{pmatrix} \frac{1}{2\varphi} & -\frac{\varphi}{2} & \frac{1}{2} \\ \frac{\varphi}{2}  & \frac{1}{2}     & \frac{1}{2\varphi} \\ -\frac{1}{2}    & \frac{1}{2\varphi} & \frac{\varphi}{2} \end{pmatrix}, \quad M_2= \begin{pmatrix} 0 & 0 & 1 \\         1  & 0 & 0 \\         0  & 1 & 0 \end{pmatrix}. $$ $M_{1}$ represents the rotation around the axis $(0, 1, φ)$ through an angle of $2\pi⁄5$ counterclockwise, while $M_{2}$ being a cyclic shift of $(x, y, z)$ represents the rotation around the axis $(1, 1, 1)$ through an angle of $2\pi⁄3$. Then the 60 vertices of the snub dodecahedron are the 60 images of point $p$ under repeated multiplication by $M_{1}$ and/or $M_{2}$, iterated to convergence. (The matrices $M_{1}$ and $M_{2}$ generate the 60 rotation matrices corresponding to the 60 rotational symmetries of a regular icosahedron.) The coordinates of the vertices are integral linear combinations of $1, φ, ξ, φξ, ξ^{2}$ and $φξ^{2}$. The edge length equals $$2\xi\sqrt{1-\xi}\approx 0.449\,750\,618\,41.$$ Negating all coordinates gives the mirror image of this snub dodecahedron.

As a volume, the snub dodecahedron consists of 80 triangular and 12 pentagonal pyramids. The volume $V_{3}$ of one triangular pyramid is given by: $$   V_3 = \frac{1}{3}\varphi\left(3\xi^2-\varphi^2\right) \approx 0.027\,274\,068\,85, $$ and the volume $V_{5}$ of one pentagonal pyramid by: $$   V_5 = \frac{1}{3}(3\varphi+1)\left(\varphi+3-2\xi-3\xi^2\right)\xi^3 \approx 0.103\,349\,665\,04. $$ The total volume is $$80V_3+12V_5 \approx 3.422\,121\,488\,76.$$

The circumradius equals $$\sqrt{4\xi^2-\varphi^2} \approx 0.969\,589\,192\,65.$$ The midradius equals $ξ$. This gives an interesting geometrical interpretation of the number $ξ$. The 20 "icosahedral" triangles of the snub dodecahedron described above are coplanar with the faces of a regular icosahedron. The midradius of this "circumscribed" icosahedron equals 1. This means that $ξ$ is the ratio between the midradii of a snub dodecahedron and the icosahedron in which it is inscribed.

The triangle–triangle dihedral angle is given by $$ \theta_{33} = 180^\circ - \arccos\left(\frac23\xi+\frac13\right) \approx 164.175\,366\,056\,03^\circ. $$

The triangle–pentagon dihedral angle is given by $$\begin{align} \theta_{35} &= 180^\circ - \arccos\sqrt{\frac{-(4\varphi + 8)\xi^2 - (4\varphi + 8)\xi + 12\varphi + 19}{15}} \\[2pt] &\approx 152.929\,920\,275\,84^\circ. \end{align}$$

Metric properties
For a snub dodecahedron whose edge length is 1, the surface area is $$A = 20\sqrt{3} + 3\sqrt{25+10\sqrt{5}} \approx 55.286\,744\,958\,445\,15.$$ Its volume is $$V= \frac{(3\varphi+1)\xi^2+(3\varphi+1)\xi-\varphi/6-2}{\sqrt{3\xi^2-\varphi^2}} \approx 37.616\,649\,962\,733\,36.$$ Alternatively, this volume may be written as $$\begin{align} V &= \frac{5+5\sqrt{5}}{6\sqrt{3}}\sqrt{{{18+6\sqrt{5}}} + {a \left({3+3\sqrt{5}} + a \right)} } +\frac{5+3\sqrt{5}}{24\sqrt{2}}\sqrt{ 72 + {\left({5+\sqrt{5}}\right)}a \left( + a \right)} \\[2pt] &\approx 37.616\,649\,962\,733\,36, \end{align}$$ where $$\begin{align} a &= \sqrt[3]{54(1+\sqrt{5})+6\sqrt{102+162\sqrt{5}}}+\sqrt[3]{54(1+\sqrt{5})-6\sqrt{102+162\sqrt{5}}} \\[2pt] &\approx 10.293\,368\,998\,184\,21. \end{align}$$ Its circumradius is $$R = \frac12\sqrt{\frac{2-\xi}{1-\xi}} \approx 2.155\,837\,375.$$ Its midradius is $$r=\frac{1}{2}\sqrt{\frac{1}{1-\xi}}\approx 2.097\,053\,835\,25.$$

There are two inscribed spheres, one touching the triangular faces, and one, slightly smaller, touching the pentagonal faces. Their radii are, respectively: $$\begin{align} r_3 &= \frac{\varphi\sqrt3}{6\xi}\sqrt{\frac{1}{1-\xi}}\approx 2.077\,089\,659\,74 \\[4pt] r_5 &= \frac12\sqrt{\varphi^2\xi^2 + 3\varphi^2\xi + \frac{11}{5}\varphi + \frac{12}{5}}\approx 1.980\,915\,947\,28. \end{align}$$

The four positive real roots of the sextic equation in R2 $$4096R^{12} - 27648R^{10} + 47104R^8 - 35776R^6 + 13872R^4 - 2696R^2 + 209 = 0$$ are the circumradii of the snub dodecahedron (U29), great snub icosidodecahedron (U57), great inverted snub icosidodecahedron (U69), and great retrosnub icosidodecahedron (U74).

The snub dodecahedron has the highest sphericity of all Archimedean solids. If sphericity is defined as the ratio of volume squared over surface area cubed, multiplied by a constant of 36$\pi$ (where this constant makes the sphericity of a sphere equal to 1), the sphericity of the snub dodecahedron is about 0.947.

Orthogonal projections
The snub dodecahedron  has two especially symmetric orthogonal projections as shown below, centered on two types of faces: triangles and pentagons, corresponding to the A2 and H2 Coxeter planes.

Geometric relations
The snub dodecahedron can be generated by taking the twelve pentagonal faces of the dodecahedron and pulling them outward so they no longer touch. At a proper distance this can create the rhombicosidodecahedron by filling in square faces between the divided edges and triangle faces between the divided vertices. But for the snub form, pull the pentagonal faces out slightly less, only add the triangle faces and leave the other gaps empty (the other gaps are rectangles at this point). Then apply an equal rotation to the centers of the pentagons and triangles, continuing the rotation until the gaps can be filled by two equilateral triangles. (The fact that the proper amount to pull the faces out is less in the case of the snub dodecahedron can be seen in either of two ways: the circumradius of the snub dodecahedron is smaller than that of the icosidodecahedron; or, the edge length of the equilateral triangles formed by the divided vertices increases when the pentagonal faces are rotated.)

The snub dodecahedron can also be derived from the truncated icosidodecahedron by the process of alternation. Sixty of the vertices of the truncated icosidodecahedron form a polyhedron topologically equivalent to one snub dodecahedron; the remaining sixty form its mirror-image. The resulting polyhedron is vertex-transitive but not uniform.

Alternatively, combining the vertices of the snub dodecahedron given by the Cartesian coordinates (above) and its mirror will form a semiregular truncated icosidodecahedron. The comparisons between these regular and semiregular polyhedrons is shown in the figure to the right.

Cartesian coordinates for the vertices of this alternative snub dodecahedron are obtained by selecting sets of 12 (of 24 possible even permutations contained in the five sets of truncated icosidodecahedron Cartesian coordinates). The alternations are those with an odd number of minus signs in these three sets:

$$\begin{array}{ccccccc} \Bigl(& \pm \tfrac{1}{\varphi} &,& \pm \tfrac{1}{\varphi} &,& \pm [3 + \varphi] & \Bigr), \\[2pt] \Bigl(& \pm \tfrac{1}{\varphi} &,& \pm\,\varphi^2 &,& \pm [3\varphi - 1] & \Bigr), \\[2pt] \Bigl(& \pm [2\varphi - 1] &,& \pm\,2 &,& \pm [2 + \varphi] & \Bigr), \end{array}$$ and an even number of minus signs in these two sets: $$\begin{array}{ccccccc} \Bigl(& \pm \tfrac{2}{\varphi} &,& \pm\,\varphi &,& \pm [1 + 2\varphi] & \Bigr), \\[2pt] \Bigl(& \pm\,\varphi &,& \pm\,3 &,& \pm\,2\varphi & \Bigr), \end{array}$$

where $$\varphi = \tfrac{1 + \sqrt 5}{2}$$ is the golden ratio. The mirrors of both the regular truncated icosidodecahedron and this alternative snub dodecahedron are obtained by switching the even and odd references to both sign and position permutations.

Related polyhedra and tilings
This semiregular polyhedron is a member of a sequence of snubbed polyhedra and tilings with vertex figure (3.3.3.3.n) and Coxeter–Dynkin diagram. These figures and their duals have (n32) rotational symmetry, being in the Euclidean plane for n = 6, and hyperbolic plane for any higher n. The series can be considered to begin with n = 2, with one set of faces degenerated into digons.

Snub dodecahedral graph
In the mathematical field of graph theory, a snub dodecahedral graph is the graph of vertices and edges of the snub dodecahedron, one of the Archimedean solids. It has 60 vertices and 150 edges, and is an Archimedean graph.

title: Snub dodecahedron


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Jean-François de La Harpe

Jean-François de La Harpe (20 November 1739 – 11 February 1803) was a French playwright, writer and literary critic.

Life
La Harpe was born in Paris of poor parents. His father, who signed himself Delharpe, was a descendant of a noble family originally of Vaud. Left an orphan at the age of nine, La Harpe was taken care of for six months by the Sisters of Charity, and his education was provided for by a scholarship at the Collège d'Harcourt, now known as the Lycée Saint-Louis. When nineteen he was imprisoned for some months on the charge of having written a satire against his protectors at the college. He was imprisoned at For-l'Évêque. La Harpe always denied his guilt, but this culminating misfortune of an early life spent entirely in the position of a dependent possibly had something to do with the bitterness he evinced in later life.

In 1763, his tragedy of Warwick was played before the court. This, his first play, was perhaps the best he ever wrote. The many authors whom he afterwards offended were always able to observe that the critic's own plays did not reach the standard of excellence he set up. Timoleon (1764) and Pharamond (1765) were box-office and critical failures. Mélanie was a better play, but was never represented. The success of Warwick led to a correspondence with Voltaire, who conceived a high opinion of La Harpe, even allowing him to correct his verses.

In 1764, La Harpe married the daughter of a coffee house keeper. This marriage, which proved very unhappy and was dissolved, did not improve his position. They were very poor, and for some time were guests of Voltaire at Ferney. When, after Voltaire's death, La Harpe in his praise of the philosopher ventured on some reasonable, but rather ill-timed, criticism of individual works, he was accused of treachery to one who had been his constant friend.

In 1768, he returned from Ferney to Paris, where he began to write for the Mercure de France. He was a born fighter and had little mercy on the authors whose work he handled. But he was himself violently attacked, and suffered under many epigrams, especially those of Lebrun-Pindare. No more striking proof of the general hostility can be given than his reception in 1776 at the Académie française, which Sainte-Beuve calls his "execution". Marmontel, who received him, used the occasion to eulogize La Harpe's predecessor, Charles-Pierre Colardeau, especially for his pacific, modest and indulgent disposition. The speech was punctuated by the applause of the audience, who chose to regard it as a series of sarcasms on the new member.

Eventually La Harpe was compelled to resign from the Mercure, which he had edited from 1770. On the stage he produced Les Barmecides (1778), Philoctete, Jeanne de Naples (1781), Les Brames (1783), Coriolan (1784), Virginie (1786). In 1786, he began delivering a course of literature at the newly established Lycée. In these lectures, published as the Cours de littérature ancienne et moderne, La Harpe is considered to have been at his best, finding a standpoint more or less independent of contemporary polemics. He is said to have been inexact in dealing with the ancients and that he had only a superficial knowledge of the Middle Ages, but he was excellent in his analysis of seventeenth-century writers. Sainte-Beuve found La Harpe to be the best critic of the French school of tragedy.

La Harpe was a disciple of the "philosophes", supporting their extreme party through the excesses of 1792 and 1793. In 1793, he returned to edit the Mercure de France, which blindly adhered to the revolutionary leaders. Nonetheless, in April 1794, La Harpe was seized as a "suspect". In prison he underwent a spiritual crisis which he described in convincing language, emerging an ardent Catholic and a political reactionary. When he resumed his chair at the Lycée, he attacked his former friends in politics and literature. He was sufficiently imprudent to begin the publication of his 1774-1791 Correspondance littéraire in 1801 with the grand-duke (and later emperor) Paul of Russia. In these letters he surpassed the brutalities of the Mercure.

He contracted a second marriage, which was dissolved after a few weeks by his wife. He died on 11 February 1803 in Paris, leaving in his will an incongruous exhortation to his fellow countrymen to maintain peace and concord. Among his posthumous works was a Prophétie de Cazotte, which Sainte-Beuve pronounced his best work. It is a somber description of a dinner-party of notables long before the Revolution, in which Jacques Cazotte is made to prophesy the frightful fates awaiting the various individuals of the company.

Among his works not already mentioned are: Commentaire sur Racine (1795–1796), published in 1807; Commentaire sur le théâtre de Voltaire of earlier date (published posthumously in 1814); and an epic poem La Religion (1814). His Cours de littérature has been often reprinted; a notice by Pierre Daunou prefixes the 1825–1826 edition.

Works
La Harpe wrote numerous plays, of which almost all are completely forgotten. Only Warwick and Philoctetes, imitated from Sophocles, had some success.

A particular mention must be made of Mélanie, ou les Vœux forcés, that the author had printed in 1770 but which was not played before 7 December 1791 at the Théâtre français. It remains, according to Jacques Truchet, "the most curious of his plays and the most representative of the spirit of the times." The topic - forced wishes - could suit anticlericalism that La Harpe showed when he composed this piece but much less censorship of the time, which is why it was played after the French Revolution. Although presented as a play in three acts and verse, Melanie approached the drama that would experience the fortune that we know at the end of the eighteenth.

This comparison is all the more pungent than La Harpe had always professed the greatest contempt for drama, which he violently attacked in his comedy Molière à la nouvelle salle, written in defense of the Comédie-Française against competitor theaters.

Moreover, his Correspondance littéraire addressed to Grand duke Paul I of Russia is full of theatrical anecdotes about the actors and plays of his time.

 * 1763: Le Comte de Warwick (Théâtre-Français, 7 November 1763)
 * 1764: Timoléon (Théâtre-Français, 1 August)
 * 1765: Pharamond
 * 1770: Mélanie, ou les Vœux forcés
 * 1774: Olinde et Sophronie
 * 1775: Menzicoff, ou les Exilés (Fontainebleau, November)
 * 1778: Les Barmécides (Théâtre-Français, 11 July. it was performed eleven times only Voltaire reportedly told the author: "My friend, it is not worth anything, never will tragedy happen that way".
 * 1779: Les Muses rivales, ou l’Apothéose de Voltaire (comédie en 1 acte et en vers libres, créée au Théâtre-Français 1 February 1779)
 * 1781: Jeanne de Naples, 12 December)
 * 1782: Molière à la nouvelle salle, ou les Audiences de Thalie, 12 April, comedy in 1 act and in verse
 * 1783: Philoctète, 16 June
 * 1784: Coriolan, 2 March
 * 1786: Virginie, 11 July

Critics
La Harpe's main work is his Lycée ou Cours de littérature (1799), which brings in 18 volumes of lessons he had given for twelve years in high school. It is a monument of literary criticism. Even if some parts are low - that on ancient philosophers in particular - everything that is said about the drama of Corneille to Voltaire, is beautifully thought out and reasoned, even if the thinking and reasoning is that of a purist and often picky. The passages on contemporary authors, in which La Harpe attacks vigorously the philosophical party, are often very funny.
 * 1795–1796: Commentaire sur Racine, published in 1807
 * 1796: De la Guerre déclarée par nos nouveaux tyrans à la raison, à la morale, aux lettres et aux arts
 * 1797: Réfutation du livre de l’Esprit (d’Helvétius)
 * 1797: Du Fanatisme dans la langue révolutionnaire, ou de la Persécution suscitée par les barbares du XVIIIe contre la religion chrétienne et ses ministres
 * 1798–1804: Lycée, ou, Cours de littérature ancienne et moderne. Tome premier; Tome second; Tome troisième; Tome quatrième; Tome cinquieme; Tome sixieme; Tome septième; Tome neuvième; Tome dixième; Tome onzieme; `Tome douzième; Tome treizième; Tome quatorzième; Tome quinzième; Tome seizième, 18 vol.

Varia

 * L’Alétophile ou l’ami de la Vérité (1758)
 * Héroïdes nouvelles, précédées d’un essai sur l’héroïde en général (1759)
 * Le Philosophe des Alpes. Ode qui a concouru pour le Prix de l'Académie Françoise en 1762 (1762)
 * La Délivrance de Salerne et la fondation du royaume des Deux-Siciles (1765)
 * Mélanges littéraires ou épîtres et pièces philosophiques (1765)
 * Le Poëte (epistle, crowned by the Académie française)
 * Éloge de Charles V (crowned by the Académie française)
 * Des Malheurs de la guerre et des avantages de la paix (1767) (speech, crowned by the Académie française)
 * Eloge de Henri IV, Roi de France (1769)
 * Éloge de François de Salignac de La Motte-Fénelon, archevèque-duc de Cambray, précepteur des enfans de France (1771) (crowned by the Académie française)
 * Éloge de Racine (1772)
 * La navigation (1773)
 * Éloge de La Fontaine (1774)
 * Eloge de Nicolas de Catinat, Maréchal de France (1775)
 * Conseils à un jeune poète (1775)
 * Éloge de Voltaire (1780)
 * Tangu et Filine, poème érotique (1780)
 * Abrégé de l’histoire générale des voyages, 32 parts (1780) (see: https://archive.org/search?query=%27%27Abr%C3%A9g%C3%A9+de+l%E2%80%99histoire+g%C3%A9n%C3%A9rale+des+voyages)
 * d’un solitaire de La Trappe à la lettre de l’abbé de Rancé'' (1780)
 * Le Salut public, ou la Vérité dite à la Convention (1794)
 * Acte de garantie pour la liberté individuelle, la sûreté du domicile, et la liberté de la presse (1794)
 * Oui ou Non (1795)
 * La liberté de la Presse, défendue par La Harpe, contre Chénier (1795)
 * De l'Etat des Lettres en Europe, depuis la fin du siècle qui a suivi celui d'Auguste, jusqu'au règne de Louis XIV (1797)
 * Le Pseautier en français, traduction nouvelle, avec des notes... précédée d’un discours sur l’esprit des Livres saints et le style des prophètes (1797)
 * Correspondance littéraire adressée a son altesse impériale mgr. le grand-duc, aujoud'hui empereur de Russie, et a m. le comte André Schowalow, chambellan de l'impératrice Catherine II. Tome premier; Tome second; Tome troisième; Tome quatrième, (1801-1807)
 * Le Camaldule (1802)
 * Le Triomphe de la religion, ou le Roi martyr (1814)
 * Commentaire sur le théâtre de Voltaire (1814)
 * Prédiction de Cazotte, faite en 1788 (1817)
 * Les Ruines, ou Voyage en France

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Jean-François de La Harpe


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Langdon Winner

Langdon Winner (born August 7, 1944) is Thomas Phelan Chair of Humanities and Social Sciences in the Department of Science and Technology Studies at Rensselaer Polytechnic Institute, Troy, New York.

Langdon Winner was born in San Luis Obispo, California on August 7, 1944. He received his B.A. in 1966, M.A. in 1967 and Ph.D. in 1973, all in political science at the University of California, Berkeley. His primary focus was political theory.

He has been a professor at Leiden, MIT, University of California, Los Angeles and at the University of California, Santa Cruz. Since 1985 he has been at the Rensselaer Polytechnic Institute; he was a visiting professor at Harvey Mudd College (2000) and Colgate University (2001). In 2010 he was a Fulbright Fellow visiting the Universidad Complutense in Madrid.

Winner lives in upstate New York. He is married to Gail P. Stuart and has three children. His interests include science, technology, American popular culture, and theories of sustainability.

Winner is known for his articles and books on science, technology, and society. He also spent several years as a reporter, rock music critic, and contributing editor for Rolling Stone magazine.

Technology and politics
In 1980 Winner proposed that technologies embody social relations, i.e. power. To the question he poses "Do Artifacts Have Politics?", Winner identifies two ways in which artifacts can have politics. The first, involving technical arrangements and social order, concerns how the invention, design, or arrangement of artifacts or the larger system becomes a mechanism for settling the affairs of a community. This way "transcends the simple categories of 'intended' and 'unintended' altogether", representing "instances in which the very process of technical development is so thoroughly biased in a particular direction that it regularly produces results heralded as wonderful breakthroughs by some social interests and crushing setbacks by others" (Winner, p. 25-6, 1999). It implies that the process of technological development is critical in determining the politics of an artifact; hence the importance of incorporating all stakeholders in it. (Determining who the stakeholders are and how to incorporate them are other questions entirely.)

The second way in which artifacts can have politics refers to artifacts that correlate with particular kinds of political relationships, which Winner refers to as inherently political artifacts (Winner, p. 22, 1999). He distinguishes between two types of inherently political artifacts: those that require a particular sociological system and those that are strongly compatible with a particular sociological system (Winner, p. 29, 1999). A further distinction is made between conditions internal to the workings of a given technical system and those that are external to it (Winner, p. 33, 1999). This second way in which artifacts can have politics can be further articulated as consisting of four 'types' of artifacts: those requiring a particular internal sociological system, those compatible with a particular internal sociological system, those requiring a particular external sociological system, and those compatible with a particular external sociological system.

Certain features of Winner's thesis have been criticized by other scholars, including Bernward Joerges.

Music
Winner contributed piano and backing vocals to the hoax album The Masked Marauders created by Rolling Stone. He also played piano on "Church Key" by The Revels. Winner is also notable for having written a negative review of one of the most critically acclaimed albums of the 1970's, Neil Young's After the Gold Rush.

Critique of educational technologies
Over the years one focus of Winner's criticism has been the excessive use of technologies in the classroom, both in K-12 schools and higher education. Winner's critique is well explained in his article "Information Technology and Educational Amnesia," and expressed in his satirical lecture, "The Automatic Professor Machine."

Selected articles

 * "Do Artifacts Have Politics?" in Daedalus, Vol. 109, No. 1, Winter 1980. Reprinted in The Social Shaping of Technology, edited by Donald A. MacKenzie and Judy Wajcman (London: Open University Press, 1985; second edition 1999). Also adapted in Winner's book The Whale and the Reactor: A Search for Limits in an Age of High Technology, University of Chicago Press, 1986.
 * "Engineering Ethics and Political Imagination," in Broad and Narrow Interpretations of Philosophy of Technology, edited by Paul T. Durbin (Dordrecht: Springer Netherlands, 1990), pp. 53–64.
 * "Social Constructivism: Opening the Black Box and Finding It Empty," Science as Culture, Vol. 3, Issue 3, 1993, pp. 427–452.
 * "How Technology Reweaves the Fabric of Society," The Chronicle of Higher Education, 39, Issue 48, August 4, 1993, pp. B1-B3.
 * "Sow's Ears from Silk Purses: The Strange Alchemy of Technological Visionaries," in Technological Visions: The Hopes and Fears that Shape New Technologies, edited by Marita Sturken, Douglas Thomas and Sandra J. Ball-Rokeach (Temple University Press, Philadelphia, 2004), pp. 34–47.

Selected books

 * Autonomous Technology: Technics-out-of-Control as a Theme in Political Thought, M.I.T. Press, 1977. (ISBN 978-0262730495)
 * The Whale and the Reactor: A Search for Limits in an Age of High Technology, University of Chicago Press, 1986. (ISBN 978-0226902111)
 * Technology and Democracy, (editor), Dordrecht and Boston: Reidel/Kluwer, 1992.
 * Technology and Democracy: Technology in the Public Sphere, co-edited with Andrew Feenberg and Torben Hviid Nielsen, Oslo: Center for Technology and Culture, 1997.

title: Langdon Winner


text:
Jacques Cazotte

Jacques Cazotte (17 October 1719 – 25 September 1792) was a French author and a monarchist. He predicted the Reign of Terror and was guillotined shortly after.

Life
Born in Dijon, he was educated by the Jesuits. Cazotte then worked for the French Ministry of the Marine and at the age of 27 he obtained a public office at Martinique. It was not until his return to Paris in 1760 with the rank of commissioner-general that he made his public debut as an author. His first attempts, a mock romance and a coarse song, gained so much popularity, both in the Court and among the people, that he was encouraged to try something more ambitious. He accordingly produced his romance, Les Prouesses inimitables d'Ollivier, marquis d'Edesse.

Cazotte wrote a number of fantastic oriental tales, such as his children's fairy tale La patte du chat (The Cat's Paw, 1741) and the humorous Mille et une fadaises, Contes a dormir debout (The Thousand and One Follies, Tales to Sleep Upright 1742). His first success was with a "poem" in twelve cantos, and in prose intermixed with verse, entitled Ollivier (2 vols, 1762), followed in 1771 by another romance, the Lord Impromptu. But the most popular of his works was Le Diable amoureux (The Devil in Love, 1772), a fantastic tale in which the hero raises the Devil. The value of the story lies in the picturesque setting, and the skill with which its details are carried out.

Cazotte copy-edited, adapted, and expanded French translations of tales actually and supposedly belonging to the Thousand and One Nights provided to him by the Syrian priest Dom Denis Chavis. These stories were published in Geneva in 1788–89, independently as Continuation des Mille et Une Nuits and, in the Cabinet des Fées anthology, as Suites des Mille et Une Nuits (1788–1789).

Cazotte possessed extreme facility that he is said to have dashed off a seventh canto of Voltaire's Guerre civile de Genève in a single night. Circa 1775 Cazotte, embraced the creed of the Illuminati and declared himself possessed of the power of prophecy. It was upon this event that Jean-François de la Harpe based his famous jeu d'esprit, in which he represents Cazotte as prophesying the most minute events of the French Revolution. Near the end of his life, Cazotte became a follower of the Martinist mysticism of Martinez de Pasqually, and became a "mystical monarchist". Upon the discovery of some of his counter-revolutionary letters in August 1792, Cazotte was arrested. He escaped for a time through the efforts of his daughter but was guillotined in September.

Writings
A complete edition of his work was published as the Œuvres badines et morales, historiques et philosophiques de Jacques Cazotte (4 vols, 1816–1817), though more than one collection appeared during his lifetime. Cazotte's work was an influence on later fantasy writers such as E. T. A. Hoffmann, Charles Nodier, Gérard de Nerval and Théophile Gautier.

 * Prophetie de Cazotte (Reputed)
 * Ollivier, 1762.
 * Le Diable amoureux (The Devil in Love), 1772.
 * A Thousand and One Follies, and His Most Unlooked-for Lordship. Translated by Eric Sutton, with an introduction by Storm Jameson, 1927.

title: Jacques Cazotte


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Nyala

The lowland nyala or simply nyala (Tragelaphus angasii) is a spiral-horned artiodactyl antelope native to Southern Africa. The species is part of the family Bovidae and the genus Tragelaphus (formerly placed in the genus Nyala). It was first described in 1849 by George French Angas and exhibits the highest sexual dimorphism among the spiral-horned antelopes. It is not to be confused with the endangered mountain nyala living in the Bale region of Ethiopia.

The nyala's range encompasses much of Southern Africa. As its population is relatively stable, it has been listed as of least concern by the International Union for Conservation of Nature. It generally browses during the day in warm weather and during the night in the rainy season. As a herbivore, the nyala feeds upon foliage, fruits and grasses, and requires sufficient fresh water. A shy animal, it prefers water holes rather than open spaces. The nyala does not show signs of territoriality, and individuals' areas can overlap. They are very cautious creatures.

They live in single-sex or mixed family groups of up to ten individuals, but old males live alone. They inhabit thickets within dense and dry savanna woodlands. The principal threats to the species are illegal poaching and habitat loss resulting from human settlement and livestock grazing. However, the large-horned, impressive males are highly prized as game animals by sport hunters.

Taxonomy and naming
The nyala was first described by George French Angas, an English naturalist, in 1849. The scientific name of nyala is Tragelaphus angasii. The name angasii is attributed to Angas, who said that John Edward Gray had named this species after Angas' father, George Fife Angas of South Australia. According to Article 50.1.1 of the International Code of Zoological Nomenclature and International Commission on Zoological Nomenclature, though, this is insufficient to state Gray as the author. The name "nyala" is the Tsonga name for this antelope, which is likely the source of the English, along with Zulu inyala. Its first known use was in 1899. The word has a Bantu origin, similar to the Venda word dzì-nyálà (nyala buck).

The nyala is the second taxon to branch off from the tragelaphine family tree just after the lesser kudu. As the nyala line has remained separate for a considerable time (over 5 million years), some authorities have placed it in its own monotypic genus Nyala. Nyala was proposed in 1912 by American zoologist Edmund Heller, who also proposed Ammelaphus for the lesser kudu, but it was not widely recognized. It was re-erected as a valid genus in 2011 under the classification of Peter Grubb and Colin Groves, but has not been embraced by taxonomic authorities such as the Mammal Diversity Database. Among its closest extant relatives are the forest-inhabiting bongo, the bushbuck, the large common and giant elands, the greater and lesser kudus, the mountain nyala (of Ethiopia) and the swamp-dwelling sitatunga, all of which share similar characteristics, such as hornless females, vertical side-stripes and other unique white markings, and the spiraling horns and distinct "beard" or dewlap of males, often with a raised trail of fur extending down the back and underside.

In 2005, Sandi Willows-Munro (of the University of KwaZulu-Natal) and colleagues carried out a mitochondrial DNA analysis of the nine Tragelaphus species. Mitochondrial DNA and nuclear DNA data were compared. The results showed the tribe Tragelaphini to be monophyletic, with the lesser kudu (T. imberbis) basal in the phylogeny, followed by the nyala. On the basis of mitochondrial data, studies have estimated that the lesser kudu separated from its sister clade around 13.7 million years ago. However, nuclear DNA data shows lesser kudu and nyala forming a clade, which collectively separated from the sister clade 13.8 million years ago.

Genetics and evolution
The nyala has 55 male chromosomes and 56 female chromosomes. The Y chromosome has been translocated onto the 14th chromosome, as in other tragelaphids, but no inversion of the Y chromosome occurs. Cranial studies have shown that the mountain nyala and nyala, though sharing a common name, are actually distant relatives.

Fossil evidence suggests that the nyala has been a separate species since the end of the Miocene (5.8 million years ago). Genetic evidence suggests that the proto-nyala had some early hybridization with the proto-lesser kudu, but the two have remained separate long after this crossing.

Physical description
The nyala is a spiral-horned and middle-sized antelope, between a bushbuck and a kudu. It is considered the most sexually dimorphic antelope. The nyala is typically between 135 – in head-and-body length. The male stands up to 110 cm, the female is up to 90 cm tall. Males weigh 98 - 125 kg, while females weigh 55 - 68 kg. Life expectancy of the nyala is about 19 years.

The coat is rusty or rufous brown in females and juveniles. It grows a dark brown or slate grey in adult males, often with a bluish tinge. Females and young males have ten or more white vertical stripes on their sides. Other markings are visible on the face, throat, flanks and thighs. Stripes are very reduced or absent in older males. Both males and females have a white chevron between their eyes, and a 40 - 55 cm long bushy tail white underside. Both sexes have a dorsal crest of hair running right from the back of the head to the end of the tail. Males have another line of hair along the midline of their chest and belly.

Only the males have horns. Horns are 60 - 83 cm long and yellow-tipped. There are one or two twists. The spoor is similar to that of the bushbuck, but larger. It is 5 - 6 cm long. The feces resemble round to spherical pellets. The nyala has hairy glands on its feet, which leave their scent wherever it walks.

The condition of the nyala often varies between the sexes. According to a study, this can be attributed to the differences in their body sizes. It was noted that during nutritional stress, old adults died in more numbers, of which most were males. During an attempt of blood sampling in the nyala, it was found that Vitamin E levels varied during stress.

Parasites
A study of the helminths from 77 nyalas from four game reserves in Natal revealed the presence of ten nematode species and four nematode genera, a trematode species and paramphistomes (members of superfamily Paramphistomoidea), and two cestode genera. The research discovered new parasites that the nyala was host of - namely a Cooperia rotundispiculum race, Gaigeria pachyscelis, a Gongylonema species, Haemonchus vegliai, Impalaia tuberculata, an Oesophagostomum species, a Setaria species, Trichostrongylus deflexus, Trichostrongylus falculatus, the larval stage of a Taenia species, a Thysaniezia species and Schistosoma mattheei. Ostertagia harrisi and C. rotundispiculum were the most dominant nematodes in the antelope.

Another study of 97 blood samples of South African nyalas revealed the presence of tick-borne hemoparasites (blood parasites). The methods used were polymerase chain reaction (PCR) and reverse line blot (RLB) hybridization. The dominant parasites were Theileria species, T. buffeli, T. bicornis, Ehrlichia species, Anaplasma marginale and A. bovis. Ten tick species, two louse species and a louse fly species were recovered in a study of 73 nyalas at Umfolozi, Mkuzi and Ndumu Game Reserves in northeastern KwaZulu-Natal in 1983 and 1984 and an additional six individuals in 1994. It was found that nyalas were hosts to all stages of development in Boophilus decoloratus, Rhipicephalus appendiculatus and R. muehlensi and the immature stages of Amblyomma hebraeum and Rhipicephalus maculatus. Adult males served hosts to more ticks and lice than adult females did. Also, a trypanosome was isolated from a nyala, wild-caught in Mozambique, which was diagnosed and found as akin to Trypanosoma vivax, based on biological, morphological and molecular data.

Diseases
The nyala can also suffer from myopathy. In between January 1973 and June 1981, 21 nyalas succumbed to the disease. The main symptoms were stiffness, inability to rise, and failure to suckle in newborns. Necrosis (that is, the premature death of cells in a living tissue) and mineralization were found in the skeletal muscle after a histological analysis. In the juveniles there was acute necrosis of the cardiac muscle. In adults, there was interstitial fibrosis of the cardiac muscle, along with arteriosclerosis.

In a report published in 1994 entitled "Epidemiological observations on spongiform encephalopathies in captive wild animals in the British Isles", it was noted that spongiform encephalopathy had been diagnosed in one nyala captive in a zoo. The nyala was formerly affected by the disease rinderpest, although the viral disease is considered eradicated now.

Ecology and behavior
The nyala is active mainly in the early morning and late afternoon. It browses during the day if temperatures are 20 - 30 C and during the night in rainy season. These antelopes rest in thick bushes during the hot hours of the day. The nyala is very shy and cautious in nature, and often remains hidden rather than coming out in the open. Most sightings of the nyala in the wild are at water holes. But in protected areas they become less shy and often come out in view of tourists.

Nyala groups are according to sex or mixed. Herds usually browse and drink water together. Each group consists of two to ten individuals. A study in Zinave National Park at Mozambique showed that 67% of the observations were of groups of one to three nyalas, and the rest of the herds consisted of up to 30 nyalas. Herds often broke up and re-formed. Generally adult males remain alone. Females often remain near their mothers when they have their offspring, so the relationships in female herds may be closer than those of males.

Alert and wary in nature, the nyala use a sharp, high, dog-like bark to warn others in a group of danger. This feature is mainly used by females. They also react to the alarm calls of impala, baboon and kudu. The impala has been found to react to the calls of the nyala as well. The main predators of nyala are lion, leopard, cheetah, spotted hyena, African wild dog and nile crocodile while baboons and raptorial birds are predators of juveniles.

Diet
As a herbivore, the nyala's diet consists of foliage, fruits, flowers and twigs. During the rainy season they feed upon the fresh grass. They need a regular intake of water, and thus choose places with a water source nearby. However, they are adapted to live in areas with only a seasonal availability of water. A study in Zululand showed that the nyala fed mainly in the early morning and the late afternoon. They feed at night during the rainy season.

A study in Mkhuze Game Reserve and Ndumu Game Reserve in Natal focused on the dietary habits of the impala and the nyala showed that the amount of dicotyledons in their diets varied seasonally. In the dry season, the nyala's dicotyledon diet content was 83.2% and the impala's 52%. In this season, the diet grew richer in fiber and dietary proteins were less. The reverse occurred in the rainy season. As the rainy season arrived, both species took to a diet of mainly monocotyledons, and the impala consumed more of them. The diet contained more proteins than fiber.

Another study was done to find whether the sexual dimorphism in the nyala influenced its foraging habits. Vegetation surveys were conducted with the end of each feeding bout. It was found that females spent equal periods of time foraging in all the three habitats, but males preferred sand forest more. More differences were noted, as males ate woody species at a greater average height whereas females fed from the low herbaceous layer. It was concluded that the differences resulted from varying nutritional and energetic demands according to their diverse body sizes and differing reproductive strategies.

Reproduction
The nyala breeds throughout the year, but mating peaks in spring and autumn. The reason for this is still unknown, but attributed to the photoperiod and the feeding habits of the animal. Females reach sexual maturity at 11 to 12 months of age and males at 18 months (though they are socially immature until five years old), though they begin to show active spermatogenesis at 14 months.

Before ovulation, the Graafian follicles reach a length of at least 6.7 cm. A female's estrous cycle is about 19 days long. Males will attempt to mate with the female for two days of the cycle, but she allows it for only six hours per cycle. When the male enters a females' herd during mating, he makes a display by raising his white dorsal crest, lowering his horns and moving stiffly. As in many other animals, the males fight over dominance during mating.

The kidney fat indices (KFIs) of impalas and nyalas have been studied to understand the influence of social class and reproduction on them. To determine the KFI, the kidney is removed and weighed with the fat and once again excluding the fat. The resultant difference is the amount of fat on the kidney. The more the fat, the healthier the animal. In rut, male nyalas had lower KFIs, which did not vary much with the season. Pregnant females of both nyala and impala had higher KFIs than non-pregnant ones.

There is a significant increase in corpus luteum in the last third of gestation. Gestation is of seven months. A single calf is born, weighing 5 kg. Birth takes place generally away from the sight of predators, in places such as a thicket. The calf remains hidden for up to 18 days, and the mother nurses it at regular intervals. The calf remains with its mother until the birth of the next calf, during which males in rut drive it away from the mother.

Habitat and distribution
The nyala inhabits dense lowland woodlands and thickets, mainly in southern Malawi, Mozambique, Zimbabwe, and eastern South Africa. It chooses places with good quality grasslands as well as provision of fresh water. It also inhabits lush green river country. The nyala's natural range stretches across southeast Africa from the Lower Shire Valley in Malawi through Mozambique and Zimbabwe to eastern South Africa and Eswatini.

The geographic distribution of the nyala may be based on the genetic variation. According to a study of nyala in South Africa, Mozambique, Malawi and Zimbabwe, there was a marked difference in the gene frequencies at three microsatellite loci. Mitochondrial DNA analysis revealed the presence of a unique haplotype in individuals from each location. Thus, the geographic variation in the nyala may be due to a distribution pattern based on habitat specificity.

Today nyala are found in South African protected areas in the Ndumo Game Reserve, uMkuze Game Reserve and Hluhluwe-Umfolozi Game Reserve, all in KwaZulu-Natal, as well as in Kruger National Park. As of 1999, 10–15% of nyala occurred on private land. Efforts are being made to retain the populations of nyala in Gorongosa National Park and Banhine National Park in Mozambique. Nyala also thrive in Lengwe National Park in Malawi.

Nyala have never been observed showing territoriality. Territories of either sex overlap extensively. The home ranges of males are approximately equal to that of females, about 10 km2 in area.

Threats and conservation
The major threats to the population of the nyala are poaching, habitat loss, agriculture and cattle grazing. Rinderpest outbreaks have also contributed in population loss. This species is currently of Least Concern, and the population is considered stable by both the IUCN and CITES. As of 1999, the total population of the nyala was around 32,000 individuals. More recent estimates show that South Africa has at least 30,000 nyalas, with 25,000 in KwaZulu-Natal. There are now more than 1,000 on protected areas and ranches in Eswatini. In Mozambique there are not more than 3,000, in Zimbabwe over 1,000, and numbers in Malawi have fallen from 3,000 to about 1,500. Namibia has the smallest population, at about 250.

Today over 80% of the total population is protected in national parks and sanctuaries, mostly in South African protected areas. In South Africa there is a high demand for adult males as game trophies.

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Gray (unit)

The gray (symbol: Gy) is the unit of ionizing radiation dose in the International System of Units (SI), defined as the absorption of one joule of radiation energy per kilogram of matter.

It is used as a unit of the radiation quantity absorbed dose that measures the energy deposited by ionizing radiation in a unit mass of absorbing material, and is used for measuring the delivered dose in radiotherapy, food irradiation and radiation sterilization. It is important in predicting likely acute health effects, such as acute radiation syndrome and is used to calculate equivalent dose using the sievert, which is a measure of the stochastic health effect  on the human body.

The gray is also used in radiation metrology as a unit of the radiation quantity kerma; defined as the sum of the initial kinetic energies of all the charged particles liberated by uncharged ionizing radiation in a sample of matter per unit mass. The unit was named after British physicist Louis Harold Gray, a pioneer in the measurement of X-ray and radium radiation and their effects on living tissue.

The gray was adopted as part of the International System of Units in 1975. The corresponding cgs unit to the gray is the rad (equivalent to 0.01 Gy), which remains common largely in the United States, though "strongly discouraged" in the style guide for U.S. National Institute of Standards and Technology.

Applications

The gray has a number of fields of application in measuring dose:

Radiobiology
The measurement of absorbed dose in tissue is of fundamental importance in radiobiology and radiation therapy as it is the measure of the amount of energy the incident radiation deposits in the target tissue. The measurement of absorbed dose is a complex problem due to scattering and absorption, and many specialist dosimeters are available for these measurements, and can cover applications in 1-D, 2-D and 3-D.

In radiation therapy, the amount of radiation applied varies depending on the type and stage of cancer being treated. For curative cases, the typical dose for a solid epithelial tumor ranges from 60 to 80 Gy, while lymphomas are treated with 20 to 40 Gy. Preventive (adjuvant) doses are typically around 45–60 Gy in 1.8–2 Gy fractions (for breast, head, and neck cancers).

The average radiation dose from an abdominal X-ray is 0.7 millisieverts (0.0007 Sv), that from an abdominal CT scan is 8 mSv, that from a pelvic CT scan is 6 mGy, and that from a selective CT scan of the abdomen and the pelvis is 14 mGy.

Radiation protection
The absorbed dose also plays an important role in radiation protection, as it is the starting point for calculating the stochastic health risk of low levels of radiation, which is defined as the probability of cancer induction and genetic damage. The gray measures the total absorbed energy of radiation, but the probability of stochastic damage also depends on the type and energy of the radiation and the types of tissues involved. This probability is related to the equivalent dose in sieverts (Sv), which has the same dimensions as the gray. It is related to the gray by weighting factors described in the articles on equivalent dose and effective dose.

The International Committee for Weights and Measures states: "In order to avoid any risk of confusion between the absorbed dose D and the dose equivalent H, the special names for the respective units should be used, that is, the name gray should be used instead of joules per kilogram for the unit of absorbed dose D and the name sievert instead of joules per kilogram for the unit of dose equivalent H."
 * $$1 \ \mathrm{Gy} = 1\ \frac{\mathrm{J}}{\mathrm{kg}}= 1\ \frac{\mathrm{m}^2}{\mathrm{s}^{2}}$$

The accompanying diagrams show how absorbed dose (in grays) is first obtained by computational techniques, and from this value the equivalent doses are derived. For X-rays and gamma rays the gray is numerically the same value when expressed in sieverts, but for alpha particles one gray is equivalent to 20 sieverts, and a radiation weighting factor is applied accordingly.

Radiation poisoning
The gray is conventionally used to express the severity of what are known as "tissue effects" from doses received in acute exposure to high levels of ionizing radiation. These are effects that are certain to happen, as opposed to the uncertain effects of low levels of radiation that have a probability of causing damage. A whole-body acute exposure to 5 grays or more of high-energy radiation usually leads to death within 14 days. LD1 is 2.5 Gy, LD50 is 5 Gy and LD99 is 8 Gy. The LD50 dose represents 375 joules for a 75 kg adult.

Absorbed dose in matter
The gray is used to measure absorbed dose rates in non-tissue materials for processes such as radiation hardening, food irradiation and electron irradiation. Measuring and controlling the value of absorbed dose is vital to ensuring correct operation of these processes.

Kerma
Kerma ("kinetic energy released per unit mass") is used in radiation metrology as a measure of the liberated energy of ionisation due to irradiation, and is expressed in grays. Importantly, kerma dose is different from absorbed dose, depending on the radiation energies involved, partially because ionization energy is not accounted for. Whilst roughly equal at low energies, kerma is much higher than absorbed dose at higher energies, because some energy escapes from the absorbing volume in the form of bremsstrahlung (X-rays) or fast-moving electrons.

Kerma, when applied to air, is equivalent to the legacy roentgen unit of radiation exposure, but there is a difference in the definition of these two units. The gray is defined independently of any target material, however, the roentgen was defined specifically by the ionisation effect in dry air, which did not necessarily represent the effect on other media.

Development of the absorbed dose concept and the gray

Wilhelm Röntgen discovered X-rays on November 8, 1895, and their use spread very quickly for medical diagnostics, particularly broken bones and embedded foreign objects where they were a revolutionary improvement over previous techniques.

Due to the wide use of X-rays and the growing realisation of the dangers of ionizing radiation, measurement standards became necessary for radiation intensity and various countries developed their own, but using differing definitions and methods. Eventually, in order to promote international standardisation, the first International Congress of Radiology (ICR) meeting in London in 1925, proposed a separate body to consider units of measure. This was called the International Commission on Radiation Units and Measurements, or ICRU, and came into being at the Second ICR in Stockholm in 1928, under the chairmanship of Manne Siegbahn.

One of the earliest techniques of measuring the intensity of X-rays was to measure their ionising effect in air by means of an air-filled ion chamber. At the first ICRU meeting it was proposed that one unit of X-ray dose should be defined as the quantity of X-rays that would produce one esu of charge in one cubic centimetre of dry air at 0 °C and 1 standard atmosphere of pressure. This unit of radiation exposure was named the roentgen in honour of Wilhelm Röntgen, who had died five years previously. At the 1937 meeting of the ICRU, this definition was extended to apply to gamma radiation. This approach, although a great step forward in standardisation, had the disadvantage of not being a direct measure of the absorption of radiation, and thereby the ionisation effect, in various types of matter including human tissue, and was a measurement only of the effect of the X-rays in a specific circumstance; the ionisation effect in dry air.

In 1940, Louis Harold Gray, who had been studying the effect of neutron damage on human tissue, together with William Valentine Mayneord and the radiobiologist John Read, published a paper in which a new unit of measure, dubbed the gram roentgen (symbol: gr) was proposed, and defined as "that amount of neutron radiation which produces an increment in energy in unit volume of tissue equal to the increment of energy produced in unit volume of water by one roentgen of radiation". This unit was found to be equivalent to 88 ergs in air, and made the absorbed dose, as it subsequently became known, dependent on the interaction of the radiation with the irradiated material, not just an expression of radiation exposure or intensity, which the roentgen represented. In 1953 the ICRU recommended the rad, equal to 100 erg/g, as the new unit of measure of absorbed radiation. The rad was expressed in coherent cgs units.

In the late 1950s, the CGPM invited the ICRU to join other scientific bodies to work on the development of the International System of Units, or SI. The CCU decided to define the SI unit of absorbed radiation as energy deposited by reabsorbed charged particles per unit mass of absorbent material, which is how the rad had been defined, but in MKS units it would be equivalent to the joule per kilogram. This was confirmed in 1975 by the 15th CGPM, and the unit was named the "gray" in honour of Louis Harold Gray, who had died in 1965. The gray was thus equal to 100 rad. Notably, the centigray (numerically equivalent to the rad) is still widely used to describe absolute absorbed doses in radiotherapy.

The adoption of the gray by the 15th General Conference on Weights and Measures as the unit of measure of the absorption of ionizing radiation, specific energy absorption, and of kerma in 1975 was the culmination of over half a century of work, both in the understanding of the nature of ionizing radiation and in the creation of coherent radiation quantities and units.

Radiation-related quantities
The following table shows radiation quantities in SI and non-SI units.

title: Gray (unit)


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Charles Pinot Duclos

Charles Pinot (or Pineau) Duclos (12 February 1704 – 26 March 1772) was a French author and contributor to the Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers.

Biography
Duclos was born at Dinan in Brittany and studied at Paris. After some time spent in dissipation he began to cultivate the society of wits and joined a club of young men who published their literary efforts under such titles as Recueil de ces messieurs, Étrennes de la saint Jean, Œufs de Pâques etc. His romance Acajou et Zirphile was the result of a wager among the club's members: Duclos composed it for a series of engraved plates intended for another work. He wrote two other romances which were favorably received: The Baroness de Luz (1741) and Confessions of Count de *** (1747).

Académie française
Duclos became a member of the Academy of Inscriptions in 1739 and of the Académie Française in 1747, being appointed perpetual secretary. In 1747, both academies were indebted to him not only for many valuable contributions, but also for several useful regulations and improvements. As a member of the Academy of Inscriptions, he composed several memoirs on trial by combat, on the origin and revolutions of the Celtic and French languages, and on scenic representations and the ancient drama. As a member of the Académie française, he assisted in compiling the new edition of the Dictionary, which was published in 1762; and he made some just and philosophical remarks on the Port Royal Grammar. On several occasions he distinguished himself by vindicating the honour and prerogatives of the societies to which he belonged, and the dignity of the literary character in general. He used to say of himself, "I shall leave behind me a name dear to literary men.". He was elected a Fellow of the Royal Society in 1764.

Mayor
The citizens of Dinan, whose interests he always supported with zeal, appointed him mayor of their town in 1744, though he was resident at Paris, and in this capacity he took part in the assembly of the estates of Brittany. Upon the requisition of this body the king granted him letters of nobility. In 1763 he was advised to retire from France for some time, having rendered himself obnoxious to the government by the opinions he had expressed on the dispute between the duc d'Aiguillon, and M. de La Chalotais, the friend and countryman of Duclos. Accordingly, he set out first for England (1763), then for Italy (1766); and on his return he wrote his Considerations on Italy. He died in Paris.

Legacy
As a character, Duclos was considered a mixture of impulsiveness and prudence. Jean-Jacques Rousseau described him laconically as a man droit et adroit. In his manners he displayed a bluntness that frequently rendered him disagreeable; and his caustic wit made him enemies. To those who knew him, however, he was a pleasant companion. A considerable number of his bons mots have been preserved by his biographers.

Works
His first serious publication was the History of Louis XI, which is dry and epigrammatical in style but displays considerable powers of research and impartiality. The reputation of Duclos as an author was confirmed by the publication of his Considérations sur les mœurs de ce siècle (1751), a work justly praised by La Harpe as containing a great deal of sound and ingenious reflection. It was translated into English and German. The Mémoires pour servir à l'histoire du dix-huitième siècle, intended by the author as a sort of sequel to the preceding work, are much inferior in style and matter, and are, in reality, little better than a kind of romance. In consequence of his History of Louis XI, he was appointed historiographer of France, when that place became vacant on Voltaire's retirement to Prussia. His Secret Memoirs of the Reigns of Louis XIV and Louis XV (for which he was able to utilize the Mémoires of Louis de Rouvroy, duc de Saint-Simon, suppressed in 1755), were not published until after the French Revolution.

A complete edition of the works of Duclos, including an unfinished autobiography, was published by Auger (1821). See also Sainte-Beuve, Causeries du lundi, t. ix.; René Kerviler, La Bretagne et l'Académie française du XVIIIe siècle (1889); L. Mandon, De la valeur historique des mémoires secrets de Duclos (1872).

title: Charles Pinot Duclos


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Charlie McCreevy

Charles McCreevy (born 30 September 1949) is an Irish former Fianna Fáil politician who served as European Commissioner for Internal Market and Services from 2004 to 2010, Minister for Finance from 1997 to 2004, Minister for Tourism and Trade from 1993 to 1994 and Minister for Social Welfare from 1992 to 1993. He served as a Teachta Dála (TD) for the Kildare constituency (and later the Kildare North constituency) from 1977 to 2004.

Early life and career
Born in Sallins, County Kildare, McCreevy was educated locally at Naas by the Congregation of Christian Brothers at Naas C.B.S., and later at Gormanston College. He studied commerce at University College Dublin and went on to become a chartered accountant. His family background was modest, his father and ancestors since the late 18th century was a lock-keeper on the Grand Canal, a job carried on by his mother, after the death of his father, when McCreevy was four years old.

Thus, his post-compulsory education was attained by winning scholarships. His political career began with when he won a seat in the Kildare constituency at the 1977 general election, which was a landslide for Charles Haughey's supporters in Fianna Fáil and he was re-elected at every subsequent election until he joined the European Commission. Between 1979 and 1985, he served as an elected member of the Kildare County Council.

Relationship with Charles Haughey
In the December 1979, Fianna Fáil leadership contest, McCreevy strongly supported the controversial Charles Haughey, who narrowly won the post. However, in a time of severe budgetary difficulties for Ireland, McCreevy soon became disillusioned with the new Taoiseach and his fiscal policies. In October 1982, McCreevy launched a motion of no-confidence in the party leader, which evolved into a leadership challenge by Desmond O'Malley. In an open ballot and supported by only 21 of his 79 colleagues (known as the "Gang of 22"), the motion failed and McCreevy was temporarily expelled from the parliamentary party.

In later years O'Malley was expelled from Fianna Fáil itself and formed the Progressive Democrats (PDs), espousing conservative fiscal policies. Although considered ideologically close to the PDs, and a personal friend of its erstwhile leader, Mary Harney, McCreevy chose to remain a member of Fianna Fáil, where he would eventually serve in joint FF-PD Governments.

Early ministerial career
For his first 15 years as TD, while Haughey remained leader, McCreevy remained a backbencher. In 1992, Albert Reynolds became Taoiseach and McCreevy was appointed Minister for Social Welfare. In this role, he is principally remembered for a set of 12 cost-cutting measures, collectively termed the "dirty dozen", which were arguably minor in their direct impact but provided a major political headache for his party in the 1992 general election.

In 1993, he became Minister for Tourism and Trade, which he held until the government fell in December 1994. In opposition under new Fianna Fáil leader Bertie Ahern, McCreevy was appointed Opposition Spokesperson for Finance. In this role he was viewed as actively pro-enterprise, anti-spending and a key advocate for tax cuts.

Minister for Finance
In 1997, Fianna Fáil returned to power and McCreevy became Minister for Finance. His period coincided with the era of the "Celtic Tiger", which saw the rapid growth of the Irish economy due to social partnership between employers, government and unions; increased female participation in the labour force, decades of tuition-free secondary education; targeting of foreign (primarily U.S.) direct investment; a low corporation tax rate; an English-speaking workforce only five time-zones from New York, and membership of the European Union – which provided payments for infrastructural development, export access to the Single Market and a Eurozone country.

McCreevy was a consistent advocate of cutting taxes and spending. As Minister for Finance, he had an opportunity to implement these policies. During his term in Finance, he made many changes to simplify the tax system and presided over Ireland's entry to Economic and Monetary Union of the European Union and later, the changeover to the Euro. He maintained a significant surplus during his seven years in Finance by forecasting tax takes which were lower than average. He simultaneously implemented a tax-cutting programme, major increases in health, education and pension spending as well as increasing investment in infrastructural development to 5% of GDP.

Unemployment fell from 10% to 4.4%. Real GDP growth fell steadily, however, from a peak of over 11% in 1997 when McCreevy took office to just over 4% in 2004. Real GDP growth across the full period of the Celtic Tiger represented by far the highest average of any western European country. Inflation was increased from 1.5% in 1997, to 5.5% in 2000, before falling steadily to just over 2% in 2004.

From 1997 to 2000, McCreevy cut Capital Gains Tax from 40% to 20%, and extended Section 23 Tax allowances to the Upper Shannon Area (against the advice of the Finance Department) in the Finance Acts of 1998 and 1999. These included special tax incentives targeted at the area covered by the pilot Rural Renewal Scheme, which was later criticised by the Heritage Council for being introduced without a "Baseline Audit" to inform the level and scale of development to be supported through the scheme, not identifying priority areas suitable for development, not providing any strategic protection for designated areas including the corridor of the River Shannon nor promoting the use of sustainable design and building materials in any new build or refurbishment project supported by the scheme.

These two measures of cutting Capital Gains Tax and providing tax incentives for property development in thinly populated rural areas have been partly responsible for the explosion in housing and commercial property speculation, which led ultimately to the collapse of the Irish banking system.

Frequently outspoken, McCreevy sometimes made comments which attracted controversy. For example, McCreevy once referred to the Irish health system as a "black hole" and reacted to the initial Irish rejection of the Nice Treaty as "a sign of a healthy democracy". He later explained this as reflecting a wake-up call to politicians and others who, like him, had expected an almost automatic Yes vote. McCreevy also prompted warnings from the European Commission, who claimed that his £2 billion tax giveaway in 2000 would be inflationary, and harmful to the Irish economy.

One of McCreevy's initiatives as Minister for Finance was decentralisation, involving moving government departments and state agencies to other parts of the country and moving 10,000 public servants with them. This target was never reached, with only 3,159 jobs having moved outside of Dublin and a wide range of state agencies having remained in Dublin. The project was abandoned in 2011, with the government having spent close to €100 million on offices that mostly remained unused.

In 2008, as Ireland entered recession, McCreevy's stewardship has been cited as one of the reasons why the global financial crisis hit Ireland especially hard, due to his "light touch" regulation of the financial system. Former Taoiseach Garret FitzGerald attributed Ireland's dire economic state in 2009, on a series of "calamitous" government policy errors by the then Finance Minister Charlie McCreevy, who between the years of 2000 and 2003, boosted public spending by 48pc while cutting income tax.

In 2015, McCreevy gave evidence to the Oireachtas Joint Committee of Inquiry into the country's banking crisis and denied his policies as minister had contributed to the crisis. A legal warning was given to McCreevy at the Banking Inquiry after he refused to answer, when asked, if he believed there had been a property bubble, but then accepted that from 2003 there had been a property bubble.

European Commissioner
In 2004, McCreevy was selected by the Government of Ireland to replace David Byrne as Ireland's European Commissioner. He was appointed to the Internal Market and Services portfolio, by President of the European Commission José Manuel Barroso. At his confirmation hearings in the European Parliament MEPs described him as "fluent and relaxed". He also informed them that he had campaigned for the ratification of every European Treaty since 1972. "'You will find me ready to meet, discuss, listen and argue on how best to deliver to our citizens the real benefits of an Internal Market. There are enormous challenges facing the EU in the coming period on which we all must find common ground. I want our policies to show that EU means something real and positive to the people in Europe.'"

When McCreevy resigned his Dáil seat on his appointment to the European Commission, his son, Charlie Jnr, declined the opportunity to be the Fianna Fáil candidate in the resulting by-election. The seat was won by the independent candidate, Catherine Murphy.

McCreevy sided with the major record labels who are trying to extend a fifty-year copyright exemption to ninety five years. In 2008, McCreevy was a supporter of attempts to introduce software patents in the European Union.

Following his departure from the commission, McCreevy was forced to resign from the board of a new banking firm, NBNK Investments, after an EU ethics committee found a conflict of interest with his work as a European Commissioner in charge of financial regulation. This is first time that a former member of the EU executive had to resign a directorship the 2003 system for overseeing the work of retired commissioners.

Northern Rock Crisis
In October 2007, McCreevy, commenting on the Northern Rock Bank's loss of investor confidence, claimed that banking regulations in the UK which forces banks to be open to scrutiny from outside investors, caused the panic. He said if access to the banks dealings "had been restricted", then the trouble could have been avoided.

Lisbon Treaty ratification 2008
Irish constitutional law requires a referendum to alter the constitution for such a major change as the adoption of the Lisbon Treaty. Interviewed beforehand, McCreevy said that he had not read the Treaty in full himself, though he understood and endorsed it:
 * "I don't think there's anybody in this room who has read it cover to cover. I don't expect ordinary decent Irish people will be sitting down spending hours reading sections about sub-sections referring to other articles and sub-articles, but there is sufficient analysis done and people have put together a consolidated text which is quite easy to read ...Anyone who thinks that, as the reality and inevitability of EU enlargement has taken hold, that we can continue to tackle urgent problems without streamlining of the decision-making process is failing to face up to reality."

In the event, the referendum was held on 12 June and the Irish electorate did not approve the Treaty. McCreevy was heavily criticised in the European Parliament, by the leader of the Socialist group in the European Parliament, Martin Schulz, who demanded on 17 June 2008, that McCreevy be removed as a European Commissioner. Schulz slightly misquoted McCreevy, whom he stated had contributed to Ireland's rejection of the Lisbon Treaty with remarks during the referendum campaign that no "sane person" would read the document."'This man goes to Ireland and says he has not read the treaty and tells people there is no need to read it,' Mr Schultz said during a heated debate on the referendum at the European Parliament in Strasbourg today.'"

Other interests
McCreevy is a member of the Bilderberg Group.

McCreevy joined the board of Sports Direct International plc on 31 March 2011 and is also a director of Ryanair. He receives annual pension payments of €119,177.

title: Charlie McCreevy


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David Andrews (politician)

David Andrews (born 15 March 1935) is an Irish former Fianna Fáil politician who served as Minister for Foreign Affairs from 1992 to 1993 and 1997 to 2000, Minister for Defence from 1993 to 1994 and June 1997 to October 1997, Minister for the Marine from 1993 to 1994, Minister of State at the Department of Foreign Affairs from 1977 to 1979 and Government Chief Whip and Minister of State at the Department of Defence from 1970 to 1973. He served as a Teachta Dála (TD) from 1965 to 2002.

Andrews was first elected to Dáil Éireann at the 1965 general election as a Fianna Fáil TD for the Dún Laoghaire and Rathdown constituency. In May 1970, in a reshuffle following the Arms Crisis, he was appointed as Parliamentary Secretary to the Taoiseach, with special responsibility as Chief Whip, and Parliamentary Secretary to the Minister for Defence. He served until Fianna Fáil left office in 1973.

Following the 1977 general election, Fianna Fáil was back in office and Jack Lynch appointed Andrews as Parliamentary Secretary to the Minister for Foreign Affairs. In the 1979 Fianna Fáil leadership election Andrews supported George Colley, the favoured candidate of the existing leadership. However, Charles Haughey, in a very close vote, was elected party leader and Taoiseach.

Andrews was confined to the backbenches during Haughey's thirteen-year period as leader. During this period he maintained his legal practice and campaigned for the Guildford Four, the Birmingham Six, and Brian Keenan. He remained a vocal critic of Haughey during this period. After the Progressive Democrats were founded in 1985 Andrews considered joining the new party. In February 1992, Albert Reynolds succeeded Haughey as Taoiseach, and Andrews was appointed as Minister for Foreign Affairs. In January 1993, following the formation of a coalition with the Labour Party, Andrews was appointed as Minister for Defence and Minister for the Marine. He served until this government fell in December 1994.

After the 1997 general election, Fianna Fáil returned to office in coalition with the Progressive Democrats, with Bertie Ahern as Taoiseach. Andrews was first appointed Minister for Defence; later that year, after the resignation of Ray Burke, he was appointed as Minister for Foreign Affairs. His period as Foreign Minister was successful regarding the Northern Ireland peace talks. In April 1998, the Good Friday Agreement was signed and was later approved in referendums in Ireland and Northern Ireland. In 1999, Ireland joined the Partnership for Peace project. Andrews stepped down as Minister for Foreign Affairs in January 2000.

He retired from politics at the 2002 general election, and his son Barry was elected for the Dún Laoghaire constituency. His other son David Andrews, Jnr is a comedian who works under the stage name of David McSavage. His brother Niall Andrews was a TD and MEP.

In May 2000, he was appointed to the non-executive position as Chairman of the Irish Red Cross Society, serving in that position until 2009.

title: David Andrews (politician)


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Talk:A capella

We could probably discuss this spelling for ever. Somebody has even created a web page about it.

According to The American Heritage® Dictionary of the English Language, Fourth Edition, the most widely accepted spelling is a cappella. Many web pages   and the A-Cappella Music FAQ agree.

Some writers   use a cappella in their own writing, reserving a capella for quotations, titles and meta tags, acknowleding it to be incorrect. Others, and The Columbia Guide to Standard American English, acknowledge what people are actually writing and hedge their bets, accepting a capella as a valid alternative spelling. The Merriam-Webster Dictionary takes this position, yet also confirms that Capelle means goat and is the name of a star.

Some apparently authoritative sources also concede acappella as a most popular de facto usage.

Some writers use both a cappella and a capella without appearing to notice the variation. Sometimes they are humorous.

One widely quoted purist  in support of a cappella alleges
 * In truth, a capella means in your hair, a cappello means in your hat, and A Capella is an astronomical reference to the first planet circling the star Capella in the constellation Auriga.

The popular vote: Google finds 247,000 hits for a capella, 205,000 for a cappella and 77,600 for acappella. EdH 15:34, 3 Aug 2003 (UTC)

title: Talk:A capella


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Todd Andrews

Christopher Stephen "Todd" Andrews (6 October 1901 – 11 October 1985) was an Irish republican and public servant. He participated in the Irish War of Independence and Civil War as a political and military activist in the Irish Republican movement. Todd Andrews never ran for election and never held public office.

Early life and education
Andrews was born at 42 Summerhill in Dublin in 1901. He acquired the nickname "Todd" because of his perceived resemblance to English comic strip hero Alonzo Todd, who appeared in The Magnet. Andrews briefly attended St. Enda's School and completed his secondary education at Synge Street CBS. He went on to study Commerce at University College Dublin, and although his studies were interrupted by his participation in the Irish War of Independence and the Irish Civil War, he returned to the university where he obtained a degree in Commerce.

Nationalist revolutionary
Andrews was politicised by the 1916 Rising. He joined the Irish Volunteers at the age of fifteen and had an active role in the Irish Republican Army during the Irish War of Independence, fighting with the Rathfarnham company of the 4th Dublin Brigade. He was arrested and imprisoned in 1920 but released after ten days on hunger strike. He was interned at the Curragh in 1921 but tunnelled his way to freedom with two comrades. Andrews took the republican side during the Irish Civil War and was wounded in the fighting in O'Connell Street, Dublin. Andrews was appointed the IRA's General Headquarters and travelled the country supervising the training of volunteers. Andrews was interned by the government of the Irish Free State until early 1924.

Public servant
After graduation, Andrews found employment as an accountant with the then-fledgling Irish Tourist Association where he structured their accounts office, as well as editing several of their publications. In the summer of 1930 he was offered a position as an accountant with the Electricity Supply Board at a time when they were expanding the National Grid and constructing significant Hydro-Electric projects such as Ardnacrusha.

In 1933, Andrews was appointed to the Department of Industry and Commerce, where he dealt with the industrialisation of Irish turf development. Andrews initially set up a network of co-ops that locally harvested and sold turf but quickly saw that this arrangement was insufficient to successfully modernise turf production in Ireland on a commercial scale; it also drew the ire of coal merchants who worried about the effect of a State-led competition to their markets. However such worries were overcome by Andrews through shrewd and active man management, culminating with the establishment of the Turf Development Board in 1934. The new semi-state company helped overcome future issues in managing peat harvesting on a grand scale and schemes set up to help fuel Ireland during The Emergency, and ultimately led to the formation of Bord Na Mona in 1946, a body that he ultimately became Chief Executive of.

CIE
In 1958 Andrew was offered and accepted the chairmanship of the Irish transport company Córas Iompair Éireann (CIÉ), which was in a perilous fiscal state. Following on from the findings of the Beddy Report, he drew from his business experience and oversaw a large restructuring of the Irish rail system. This included the purchase of diesel electric engines from General Motors, the introduction of modern coaching stock, the phased closure of uneconomic services and elimination of slow stopping services, the introduction of new braked good wagons as well as a revamp of ticketing arrangements. He also oversaw the closures of several lines that were perennially uneconomic and loss-making. This included:
 * The Bray to Harcourt Street railway line. The closure of the Harcourt Street line is undoubtedly the most infamous railway closure in Ireland. The line had not been profitable for decades, in spite of it seeing many cost-cutting measures to try and improve business. Electric signalling, AEC railcars and summer special trains to Wicklow and Wexford had been introduced on the line to try and increase its footfall and to lover costs to no avail. On foot of a recommendation of the Beddy Report, the line ceased services on 31 December 1958 and formally abandoned in January 1959. As the city expanded outwards in the mid and late 1970s the route was kept clear and partially reopened as part of the LUAS Green Line.
 * The substantial railway network west of Cork city. This included lines to Bandon, Bantry and Macroom, and branch lines to Clonakility, Skibbereen and Kinsale. Again, the lines struggled for business and saw diminishing business as cars, buses and lorries became more affordable and able to address passenger needs more practically.
 * The Hill of Howth Tramway, which was inherited from the Great Northern Railway. This anomalous line was built around Howth Head to exploit an expected tourism boom in the seaside village that never came to be. While the line served its sparse locality quite well it never turned a profit and escaped closure several times while under the auspices of the Great Northern Railway Board. However, its infrastructure and rolling stock had not been replaced during its lifetime and, with this weighed against a need for essential cost-cutting, its closure was inevitable giving CIE's poor fiscal state and statutory requirements to become profitable.
 * The West Clare Railway. Again, this line's came against a backdrop of cost-cutting but unlike other narrow gauge lines it saw the introduction of a fleet of modern diesel locomotives and railcars. While the new stock improved service levels and economics of the lines considerably they weren't enough to save the line.
 * The Cahersiveen, Kenmare and Kanturk lines. As was common with many rural railways the traffic levels on these three lines were sparse. The branches to Kanturk and Kenmare has diesel engines allocated to them too, but to no avail.

Andrews also oversaw the resurgence and modernisation of CIE road transport, provincial and city bus services in Ireland. Steam traction was eliminated under his chairmanship, a cost benefit that undoubtedly saved CIE from certain collapse, while modern van and lorries took on delivery of freights in place of horse and carriage. In spite of such economies, CIE still struggled under a state expectation that it run without subvention; an impossible ask given the sparse traffic and passenger numbers in a land cropped by emigration. Issues of Partition often affected the operation of the company; CIE was forced to introduce additional bus services in border areas upon the withdrawal of the Ulster Transport Authority from cross border services, notably with the GNRB in 1958 and the County Donegal Railway Joint Committee in 1959. In spite of all this, many people believe CIE was in a far improved condition that Andrews took up in 1958. Others take the opposite view.

RTÉ
He retired from CIE upon his 65th birthday but before he stood down he became chairman of the RTÉ Authority at the request of Seán Lemass. During his time as chairman he oversaw significant changes as the broadcaster expanded RTÉ Radio and Television, as well as the introduction of FM radio and colour television, the opening of a Belfast news desk, the beginning of the move from the GPO to a new complex at Montrose, Donnybrook. Andrews frequently rebutted Government interference in the organisation, even rebutting advances from then Minister Erskine Childers to suppress some employees who were suspected of being subversives. Todd resigned from RTÉ in 1970 after his son David Andrews was appointed Chief Whip to the Taoiseach.

Later life and family
He was the recipient of several honorary doctorates and degrees from various universities. He published his autobiography in two volumes in 1979 and 1982, under the titles of Dublin Made Me and Man of No Property.

Andrews died in Dublin at the age of 84.

Two of his sons, Niall Andrews and David Andrews, became TDs; David Andrews became Minister for Foreign Affairs.

His brother, Paddy Andrews was a football player, most notably with Bohemians who was also capped by the Irish Free State. Todd Andrews' grandson Ryan Tubridy was a radio presenter and television chatshow host on RTÉ, while grandsons Barry Andrews and Chris Andrews were also TDs. Another grandson is comedian David McSavage.

Gay Byrne, one of Tubridy's predecessors on The Late Late Show, in his 1989 memoir The Time of My Life and subsequently in an RTÉ documentary in 2005, related how Andrews, when chairman of the RTÉ Authority, phoned the Director General of RTÉ Tim McCourt and ordered him to fire "that fucker Byrne"; McCourt refused to dismiss Byrne.

Autobiography

 * Dublin Made Me (Lilliput, 2001) ISBN 978-1-901866-65-0
 * Man of no Property (Lilliput, 2001) ISBN 978-1-901866-66-7

title: Todd Andrews


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IAU designated constellations

In contemporary astronomy, 88 constellations are recognized by the International Astronomical Union (IAU). Each constellation is a region of the sky bordered by arcs of right ascension and declination, together covering the entire celestial sphere. Their boundaries were officially adopted by the International Astronomical Union in 1928 and published in 1930.

The ancient Mesopotamians and later the Greeks established most of the northern constellations in international use today, listed by the Roman-Egyptian astronomer Ptolemy. The constellations along the ecliptic are called the zodiac. When explorers mapped the stars of the southern skies, European astronomers proposed new constellations for that region, as well as ones to fill gaps between the traditional constellations. Because of their Roman and European origins, every constellation has a Latin name. In 1922, the International Astronomical Union adopted three-letter abbreviations for 89 constellations, the modern list of 88 plus Argo. After this, Eugène Joseph Delporte drew up boundaries for each of the 88 constellations so that every point in the sky belonged to one constellation.

History
Some constellations are no longer recognized by the IAU, but may appear in older star charts and other references. Most notable is Argo Navis, which was one of Ptolemy's original 48 constellations. In the 1750s the French astronomer Nicolas Louis de Lacaille divided this into three separate constellations: Carina, Puppis, and Vela.

Modern constellations
The 88 constellations depict 42 animals, 29 inanimate objects, and 17 humans or mythological characters.

Abbreviations
Each IAU constellation has an official three-letter abbreviation based on the genitive form of the constellation name. As the genitive is similar to the base name, the majority of the abbreviations are just the first three letters of the constellation name: Ori for Orion/Orionis, Ara for Ara/Arae, and Com for Coma Berenices/Comae Berenices. In some cases, the abbreviation contains letters from the genitive not appearing in the base name (as in Hyi for Hydrus/Hydri, to avoid confusion with Hydra, abbreviated Hya; and Sge for Sagitta/Sagittae, to avoid confusion with Sagittarius, abbreviated Sgr). Some abbreviations use letters beyond the initial three to unambiguously identify the constellation (for example when the name and its genitive differ in the first three letters): Aps for Apus/Apodis, CrA for Corona Australis, CrB for Corona Borealis, Crv for Corvus. (Crater is abbreviated Crt to prevent confusion with CrA.) When letters are taken from the second word of a two-word name, the first letter from the second word is capitalised: CMa for Canis Major, CMi for Canis Minor. Two cases are ambiguous: Leo for the constellation Leo could be mistaken for Leo Minor (abbreviated LMi), and Tri for Triangulum could be mistaken for Triangulum Australe (abbreviated TrA).

In addition to the three-letter abbreviations used today, the IAU also introduced four-letter abbreviations in 1932. The four-letter abbreviations were repealed in 1955 and are now obsolete, but were included in the NASA Dictionary of Technical Terms for Aerospace Use (NASA SP-7) published in 1965. These are labeled "NASA" in the table below and are included here for reference only.

List
For help with the literary English pronunciations, see the pronunciation key. There is considerable diversity in how Latinate names are pronounced in English. For traditions closer to the original, see Latin spelling and pronunciation.

Asterisms
Various other unofficial patterns exist alongside the constellations. These are known as "asterisms". Examples include the Big Dipper/Plough and the Northern Cross. Some ancient asterisms, for example Coma Berenices, Serpens, and portions of Argo Navis, are now officially constellations.

title: IAU designated constellations