Jarosite is a basic hydrous sulfate of potassium and iron with a chemical formula of KFe3+362. This sulfate mineral is formed in ore deposits by the oxidation of iron sulfides, jarosite is often produced as a byproduct during the purification and refining of zinc and is commonly associated with acid mine drainage and acid sulfate soil environments. Jarosite has a crystal structure and is brittle, with basal cleavage, a hardness of 2. 5-3.5. It is translucent to opaque with a vitreous to dull luster and it can sometimes be confused with limonite or goethite with which it commonly occurs in the gossan. Jarosite is an analogue of the potassium aluminium sulfate, alunite. The alunite supergroup includes the alunite, beudantite and florencite subgroups, the alunite supergroup minerals are isostructural with each other and substitution between them occurs, resulting in several solid solution series. The alunite supergroup has the general formula AB326, in the alunite subgroup B is Al, and in the jarosite subgroup B is Fe3+.
The beudantite subgroup has the general formula AB36, the crandallite subgroup AB325. H2O, in the jarosite-alunite series Al may substitute for Fe and a complete solid solution series between jarosite and alunite, KAl326, probably exists, but intermediate members are rare. The material from Kopec, Czech Republic, has about equal Fe and Al, in the jarosite-natrojarosite series Na substitutes for K to at least Na/K =1,2.4 but the pure sodium end member NaFe3+326 is not known in nature. Minerals with Na > K are known as natrojarosite and this indicates that there is a wide miscibility gap between the two end members, and it is doubtful whether a complete series exists between jarosite and natrojarosite. Hydroniumjarosite will only form from alkali-deficient solutions, as alkali-rich jarosite forms preferentially, divalent cations may substitute for the monovalent cation K+ in the A site. Charge balance may be achieved in three ways, firstly by replacing two monovalent cations by one divalent cation, and leaving an A site vacancy, as in plumbogummite, Pb2+Al325. H2O, which is a member of the crandallite subgroup.
Secondly by incorporating divalent ions in the B sites, as in osarizawaite, Pb2+Cu2+Al226, alunite subgroup, thirdly by replacing divalent anions with trivalent anions, as in beudantite, PbFe3+33−6, beudantite subgroup. Jarosite was first described in 1852 by August Breithaupt in the Barranco del Jaroso in the Sierra Almagrera, the name jarosite is directly derived from Jara, the Spanish name of a yellow flower that belongs to the genus Cistus and grows in this sierra. The mineral and the flower have the same color, in 2004 jarosite was detected on Mars by a Mössbauer spectrometer on the MER-B rover, which has been interpreted as strong evidence that Mars once possessed large amounts of liquid water. Jarosite is a generic term denoting an extensive family of compounds of the form AM362. In condensed matter physics and materials science they are renowned for containing layers with kagome lattice structure, alunite Iron sulfate Spirit Mars rover final embedding event Palache C. Dana’s system of mineralogy, v.
II, 560–562, webmineral data Cornell University How an obscure mineral provided a vital clue to Martian water
Geometry is a branch of mathematics concerned with questions of shape, relative position of figures, and the properties of space. A mathematician who works in the field of geometry is called a geometer, Geometry arose independently in a number of early cultures as a practical way for dealing with lengths and volumes. Geometry began to see elements of mathematical science emerging in the West as early as the 6th century BC. By the 3rd century BC, geometry was put into a form by Euclid, whose treatment, Euclids Elements. Geometry arose independently in India, with texts providing rules for geometric constructions appearing as early as the 3rd century BC, islamic scientists preserved Greek ideas and expanded on them during the Middle Ages. By the early 17th century, geometry had been put on a solid footing by mathematicians such as René Descartes. Since then, and into modern times, geometry has expanded into non-Euclidean geometry and manifolds, while geometry has evolved significantly throughout the years, there are some general concepts that are more or less fundamental to geometry.
These include the concepts of points, planes, angles, contemporary geometry has many subfields, Euclidean geometry is geometry in its classical sense. The mandatory educational curriculum of the majority of nations includes the study of points, planes, triangles, similarity, solid figures, Euclidean geometry has applications in computer science and various branches of modern mathematics. Differential geometry uses techniques of calculus and linear algebra to problems in geometry. It has applications in physics, including in general relativity, topology is the field concerned with the properties of geometric objects that are unchanged by continuous mappings. In practice, this often means dealing with large-scale properties of spaces, convex geometry investigates convex shapes in the Euclidean space and its more abstract analogues, often using techniques of real analysis. It has close connections to convex analysis and functional analysis, algebraic geometry studies geometry through the use of multivariate polynomials and other algebraic techniques.
It has applications in areas, including cryptography and string theory. Discrete geometry is concerned mainly with questions of relative position of simple objects, such as points. It shares many methods and principles with combinatorics, Geometry has applications to many fields, including art, physics, as well as to other branches of mathematics. The earliest recorded beginnings of geometry can be traced to ancient Mesopotamia, the earliest known texts on geometry are the Egyptian Rhind Papyrus and Moscow Papyrus, the Babylonian clay tablets such as Plimpton 322. For example, the Moscow Papyrus gives a formula for calculating the volume of a truncated pyramid, clay tablets demonstrate that Babylonian astronomers implemented trapezoid procedures for computing Jupiters position and motion within time-velocity space
A silhouette is the image of a person, object or scene represented as a solid shape of a single color, usually black, with its edges matching the outline of the subject. The interior of a silhouette is featureless, and the whole is typically presented on a background, usually white. The silhouette differs from an outline, which depicts the edge of an object in a linear form, while a silhouette appears as a solid shape. Silhouette images may be created in any visual media, but was first used to describe pieces of cut paper, which were stuck to a backing in a contrasting colour. Other artists, especially from about 1790, drew an outline on paper, painted it in, anything that appears this way, for example, a figure standing backlit in a doorway, may be described as in silhouette. Because of de Silhouettes austere economies, his name synonymous with anything done or made cheaply. Prior to the advent of photography, silhouette profiles cut from black card were the cheapest way of recording a persons appearance, the term silhouette, although existing from the 18th century, was not applied to the art of portrait-making until the 19th century.
The silhouette is closely tied in mythology to the origins of art, pliny the Elder, in his Natural History Books XXXIV and XXXV, recounts the origin of painting. In Chapter 5 of Book XXXV, he writes, “We have no knowledge as to the commencement of the art of painting. The Egyptians assert that it was invented among themselves, six years before it passed into Greece. As to the Greeks, some say that it was invented at Sicyon, others at Corinth, but they all agree that it originated in tracing lines round the human shadow. “. In Chapter 15, he tells the story of Butades of Corinth, “Butades, a potter of Sicyon, was the first who invented, at Corinth, the art of modelling portraits in the earth which he used in his trade. Upon seeing this, her father filled in the outline, by compressing clay upon the surface, and so made a face in relief, the pots themselves exhibit strong forms in outline that are indicators of their purpose, as well as being decorative. For this reason profile portraits have been employed on coinage since the Roman era, the early Renaissance period saw a fashion for painted profile portraits and people such as Federico da Montefeltro and Ludovico Sforza were depicted in profile portraits.
The profile portrait is linked to the silhouette. This is an important concept for artists who design characters for visual media, a silhouette portrait can be painted or drawn. However, the method of creating silhouette portraits is to cut them from lightweight black cardboard. This was the work of specialist artists, often working out of booths at fairs or markets, a traditional silhouette portrait artist would cut the likeness of a person, within a few minutes
Austria, officially the Republic of Austria, is a federal republic and a landlocked country of over 8.7 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north and Slovakia to the east and Italy to the south, the territory of Austria covers 83,879 km2. The terrain is mountainous, lying within the Alps, only 32% of the country is below 500 m. The majority of the population speaks local Bavarian dialects of German as their native language, other local official languages are Hungarian, Burgenland Croatian, and Slovene. The origins of modern-day Austria date back to the time of the Habsburg dynasty, from the time of the Reformation, many northern German princes, resenting the authority of the Emperor, used Protestantism as a flag of rebellion. Following Napoleons defeat, Prussia emerged as Austrias chief competitor for rule of a greater Germany, Austrias defeat by Prussia at the Battle of Königgrätz, during the Austro-Prussian War of 1866, cleared the way for Prussia to assert control over the rest of Germany.
In 1867, the empire was reformed into Austria-Hungary, Austria was thus the first to go to war in the July Crisis, which would ultimately escalate into World War I. The First Austrian Republic was established in 1919, in 1938 Nazi Germany annexed Austria in the Anschluss. This lasted until the end of World War II in 1945, after which Germany was occupied by the Allies, in 1955, the Austrian State Treaty re-established Austria as a sovereign state, ending the occupation. In the same year, the Austrian Parliament created the Declaration of Neutrality which declared that the Second Austrian Republic would become permanently neutral, Austria is a parliamentary representative democracy comprising nine federal states. The capital and largest city, with a population exceeding 1.7 million, is Vienna, other major urban areas of Austria include Graz, Linz and Innsbruck. Austria is one of the richest countries in the world, with a nominal per capita GDP of $43,724, the country has developed a high standard of living and in 2014 was ranked 21st in the world for its Human Development Index.
Austria has been a member of the United Nations since 1955, joined the European Union in 1995, Austria signed the Schengen Agreement in 1995, and adopted the euro currency in 1999. The German name for Austria, Österreich, meant eastern realm in Old High German, and is cognate with the word Ostarrîchi and this word is probably a translation of Medieval Latin Marchia orientalis into a local dialect. Austria was a prefecture of Bavaria created in 976, the word Austria is a Latinisation of the German name and was first recorded in the 12th century. Accordingly, Norig would essentially mean the same as Ostarrîchi and Österreich, the Celtic name was eventually Latinised to Noricum after the Romans conquered the area that encloses most of modern-day Austria, around 15 BC. Noricum became a Roman province in the mid-first century AD, heers hypothesis is not accepted by linguists. Settled in ancient times, the Central European land that is now Austria was occupied in pre-Roman times by various Celtic tribes, the Celtic kingdom of Noricum was claimed by the Roman Empire and made a province
Hunting is the practice of killing or trapping animals, or pursuing or tracking them with the intent of doing so. Hunting wildlife or feral animals is most commonly done by humans for food, recreation, to predators that are dangerous to humans or domestic animals. Lawful hunting is distinguished from poaching, which is the killing, trapping or capture of the hunted species. The species that are hunted are referred to as game or prey and are usually mammals, Hunting can be a means of pest control. However, hunting has contributed to the endangerment and extinction of many animals. The pursuit and release, or capture for food of fish is called fishing, the practice of foraging or gathering materials from plants and mushrooms is considered separate from hunting. The word hunt serves as both a noun and a verb, the noun has been dated to the early 12th century, act of chasing game, from the verb hunt. The meaning of a body of persons associated for the purpose of hunting with a pack of hounds is first recorded in the 1570s, meaning the act of searching for someone or something is from about 1600.
The verb, Old English huntian to chase game, perhaps developed from hunta hunter, is related to hentan to seize, from Proto-Germanic huntojan, the general sense of search diligently is first recorded c. Hunting has a history and may well pre-date the rise of the species Homo sapiens. Evidence from western Kenya suggests that hunting has been occurring for more two million years. Furthermore, evidence exists that hunting may have one of the multiple environmental factors leading to the Holocene extinction of megafauna. North American megafauna extinction was coincidental with the Younger Dryas impact event, however, in other locations such as Australia, humans are thought to have played a very significant role in the extinction of the Australian megafauna that was widespread prior to human occupation. The closest surviving relatives of the species are the two species of Pan, the common chimpanzee and bonobos. Common chimpanzees have a diet that includes troop hunting behaviour based on beta males being led by an alpha male.
Bonobos have observed to occasionally engage in group hunting. With the establishment of language and religion, hunting became a theme of stories and myths, as well as such as dance. Hunting was a component of hunter-gatherer societies before the domestication of livestock
Patagonia is a sparsely populated region located at the southern end of South America, shared by Argentina and Chile. The region comprises the section of the Andes mountains as well as the deserts, steppes. Patagonia has two coasts, a western one towards the Pacific Ocean and an eastern one towards the Atlantic Ocean, the Colorado and Barrancas rivers, which run from the Andes to the Atlantic, are commonly considered the northern limit of Argentine Patagonia. The archipelago of Tierra del Fuego is sometimes included as part of Patagonia, most geographers and historians locate the northern limit of Chilean Patagonia at Reloncaví Estuary. The name Patagonia comes from the word used by Magellan in 1520 to describe the native people that his expedition thought to be giants. It is now believed that the people he called the Patagons were Tehuelches, the hypothesis was accepted and published in the New Review of Spanish Philology in the 2011 article. In the hollows of the plains are ponds or lakes of fresh and brackish water, towards the Andes, the shingle gives place to porphyry and basalt lavas, animal life becomes more abundant and vegetation more luxuriant.
It is characteristic of the flora of the western coast, and consist principally of southern beech and conifers. Among the depressions by which the plateau is intersected transversely, the ones are the Gualichu, south of the Río Negro, the Maquinchao and Valcheta, the Senguerr. There, erosion which is caused principally by the sudden melting, best in evidence where in contact with folded Cretaceous rocks which are uplifted by the Cenozoic granite. It generally separates the plateau from the first lofty hills, the ridges generally called the pre-Cordillera, to the west of these, a similar longitudinal depression extends all along the foot of the snowy Andean Cordillera. This latter depression contains the richest and most fertile land of Patagonia, Lake basins along the Cordillera were excavated by ice-streams, including Lake Argentino and Lake Fagnano, as well as coastal bays such as Bahía Inútil. There have been discrepancies among geologists on the origin of the Patagonian landmass, víctor Ramos has proposed that the Patagonian landmass originated as an allochtonous terrane that separated from Antarctica and docked in South America 250 to 270 Ma in the Permian era.
A2014 study by Robert John Pankhurst and coworkers reject any idea of a far-travelled Patagonia claiming it is likely of parautochtonous origin, the Mesozoic and Cenozoic deposits have revealed a most interesting vertebrate fauna. The Patagonian Myolania belongs to the Upper Chalk, having been associated with remains of Dinosauria. In the Cenozoic marine formation, a number of cetaceans has been discovered. At a state level, Patagonia lies inside two countries and Argentina, both countries have organised their Patagonian territories into non-equivalent administrative subdivisions and departments in Argentina, and regions and communes in Chile. Being a unitary state Chiles first level administrative divisions—the regions—enjoy far less autonomy than Argentine provinces, Argentine provinces have elected governors and parliaments, while Chilean regions have government-appointed intendants
Neolithic flint mines of Spiennes
The mines were active during the mid and late Neolithic between 4,300 and 2,200 BC. Declared to be remarkable for the diversity of technological solutions used for extraction the site, discovered in 1843, the first excavations were undertaken during railway construction in 1867 and intermittent excavations have been carried out up to the present day. The Mines of Spiennes cover some 100 ha of downland four miles south-east of the city of Mons, the site is dotted with millions of scraps of worked flint and numerous mining pits, that Neolithic settlers have gradually turned into vertical mine shafts to depths of over 10 m. Research has illustrated Neolithic techniques for the cutting of the flint and the extraction of large slabs of flint, the nodules were extracted using flint picks. The stones were knapped into rough-out shapes of axes, the SILEXS Interpretive Centre has opened in spring 2015. The rough-outs were exchanged over an area, about 150 km. Polishing strengthens the product, making the axe- or adze-head last longer.
The smooth surface aids the cutting action by lowering friction with the wood, the axes were used initially for forest clearance during the Neolithic period, and for shaping wood for structural applications, such as timber for huts and canoes. The site has been compared with Grimes Graves and Cissbury in the United Kingdom, and Krzemionki in Poland, different hard rocks were used for the polished stone axes. Examples include the Langdale axe industry and Tievebulliagh, guillaume, Ph. Lipinski & A. Masson, Les mines de silex néolithiques de la Meuse dans le contexte européen. Musées de la Meuse, Sampigny 1987, F. Gosselin, Un site dexploitation du silex à Spiennes, au lieu-dit Petit-Spiennes. F. Hubert, Une minière néolithique à silex au Camp-à-Cayaux de Spiennes, F. Hubert, Lexploitation préhistorique du silex à Spiennes. Ministère de la Région wallonne, Direction générale de lAménagement du Territoire, du Logement et du Patrimoine, R. Shepherd, Prehistoric Mining and Allied Industries. Société de recherches préhistoriques en Hainaut, Minières néolithiques à Spiennes,1997 ICOMOS evaluation Collet, H.
Les mines néolithiques de Spiennes, état des connaissances et perspectives de recherche. Section 10, The Neolithic in the Near East and Europe, actes du XIVème congrès UISPP, Université de Liège, Belgique,2 –8 septembre 2001 H. Collet, A. Hauzeur & J. Lech,2008. The prehistoric flint mining complex at Spiennes on the occasion of its discovery 140 years ago In P. Allard, F. Bostyn, flint mining in Prehistoric Europe, Interpreting the archaeological records. European Association of Archaeologists, 12th Annual Meeting, Poland, 19–24 September 2006, H. Collet,2014. Les minières néolithiques de silex de Spiennes
Argentina, officially the Argentine Republic, is a federal republic in the southern half of South America. With a mainland area of 2,780,400 km2, Argentina is the eighth-largest country in the world, the second largest in Latin America, and the largest Spanish-speaking one. The country is subdivided into provinces and one autonomous city, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system, Argentina claims sovereignty over part of Antarctica, the Falkland Islands, and South Georgia and the South Sandwich Islands. The earliest recorded presence in the area of modern-day Argentina dates back to the Paleolithic period. The country has its roots in Spanish colonization of the region during the 16th century, Argentina rose as the successor state of the Viceroyalty of the Río de la Plata, a Spanish overseas viceroyalty founded in 1776. The country thereafter enjoyed relative peace and stability, with waves of European immigration radically reshaping its cultural.
The almost-unparalleled increase in prosperity led to Argentina becoming the seventh wealthiest developed nation in the world by the early 20th century, Argentina retains its historic status as a middle power in international affairs, and is a prominent regional power in the Southern Cone and Latin America. Argentina has the second largest economy in South America, the third-largest in Latin America and is a member of the G-15 and it is the country with the second highest Human Development Index in Latin America with a rating of very high. Because of its stability, market size and growing high-tech sector, the description of the country by the word Argentina has to be found on a Venice map in 1536. In English the name Argentina probably comes from the Spanish language, however the naming itself is not Spanish, Argentina means in Italian of silver, silver coloured, probably borrowed from the Old French adjective argentine of silver > silver coloured already mentioned in the 12th century. The French word argentine is the form of argentin and derives of argent silver with the suffix -in.
The Italian naming Argentina for the country implies Argentina Terra land of silver or Argentina costa coast of silver, in Italian, the adjective or the proper noun is often used in an autonomous way as a substantive and replaces it and it is said lArgentina. The name Argentina was probably first given by the Venitian and Genoese navigators, in Spanish and Portuguese, the words for silver are respectively plata and prata and of silver is said plateado and prateado. Argentina was first associated with the silver mountains legend, widespread among the first European explorers of the La Plata Basin. The first written use of the name in Spanish can be traced to La Argentina, a 1602 poem by Martín del Barco Centenera describing the region, the 1826 constitution included the first use of the name Argentine Republic in legal documents. The name Argentine Confederation was used and was formalized in the Argentine Constitution of 1853. In 1860 a presidential decree settled the name as Argentine Republic
Armenia, officially the Republic of Armenia, is a sovereign state in the South Caucasus region of Eurasia. The Republic of Armenia constitutes only one-tenth of historical Armenia, Armenia is a unitary, multi-party, democratic nation-state with an ancient cultural heritage. Urartu was established in 860 BC and by the 6th century BC it was replaced by the Satrapy of Armenia, in the 1st century BC the Kingdom of Armenia reached its height under Tigranes the Great. Armenia became the first state in the world to adopt Christianity as its official religion, in between the late 3rd century to early years of the 4th century, the state became the first Christian nation. The official date of adoption of Christianity is 301 AD. The ancient Armenian kingdom was split between the Byzantine and Sasanian Empires around the early 5th century, under the Bagratuni dynasty, the Bagratid Kingdom of Armenia was restored in the 9th century. Declining due to the wars against the Byzantines, the fell in 1045. An Armenian principality and a kingdom Cilician Armenia was located on the coast of the Mediterranean Sea between the 11th and 14th centuries.
By the 19th century, Eastern Armenia had been conquered by the Russian Empire, during World War I, Armenians living in their ancestral lands in the Ottoman Empire were systematically exterminated in the Armenian Genocide. By 1920, the state was incorporated into the Transcaucasian Socialist Federative Soviet Republic, in 1936, the Transcaucasian state was dissolved, transforming its constituent states, including the Armenian Soviet Socialist Republic, into full Union republics. The modern Republic of Armenia became independent in 1991 during the dissolution of the Soviet Union, the Republic of Armenia recognises the Armenian Apostolic Church, the worlds oldest national church, as the countrys primary religious establishment. The unique Armenian alphabet was invented by Mesrop Mashtots in 405 AD, Armenia is a member of the Eurasian Economic Union, the Council of Europe and the Collective Security Treaty Organization. Armenia supports the de facto independent Nagorno-Karabakh Republic, which was proclaimed in 1991, the native Armenian name for the country is Հայք.
The name in the Middle Ages was extended to Հայաստան, by addition of the Persian suffix -stan, the further origin of the name is uncertain. It is postulated that the name Hay comes from one of the two confederated, Hittite vassal states—the Ḫayaša-Azzi. The exonym Armenia is attested in the Old Persian Behistun Inscription as Armina, the ancient Greek terms Ἀρμενία and Ἀρμένιοι are first mentioned by Hecataeus of Miletus. Xenophon, a Greek general serving in some of the Persian expeditions, describes many aspects of Armenian village life and he relates that the people spoke a language that to his ear sounded like the language of the Persians. According to the histories of both Moses of Chorene and Michael Chamchian, Armenia derives from the name of Aram, a descendant of Hayk