The Andes or Andean Mountains are the longest continental mountain range in the world. They are a range of highlands along the western edge of South America. This range is about 7,000 km long, about 200 to 700 km wide, the Andes extend from north to south through seven South American countries, Colombia, Peru, Bolivia and Chile. Along their length, the Andes are split into several ranges, the Andes are the location of several high plateaus – some of which host major cities, such as Quito, Bogotá, Medellín, Sucre, Mérida and La Paz. The Altiplano plateau is the worlds second-highest after the Tibetan plateau and these ranges are in turn grouped into three major divisions based on climate, the Tropical Andes, the Dry Andes, and the Wet Andes. The Andes are the worlds highest mountain range outside of Asia, the highest mountain outside Asia, Mount Aconcagua, rises to an elevation of about 6,961 m above sea level. The peak of Chimborazo in the Ecuadorean Andes is farther from the Earths center than any other location on the Earths surface, the worlds highest volcanoes are in the Andes, including Ojos del Salado on the Chile-Argentina border, which rises to 6,893 m.
The etymology of the word Andes has been debated, the majority consensus is that it derives from the Quechua word anti, which means east as in Antisuyu, one of the four regions of the Inca Empire. In the northern part of the Andes, the isolated Sierra Nevada de Santa Marta range is considered to be part of the Andes. The term cordillera comes from the Spanish word cordel, meaning rope, the Andes range is about 200 km wide throughout its length, except in the Bolivian flexure where it is about 640 kilometres wide. The Andes are the result of plate tectonics processes, caused by the subduction of oceanic crust beneath the South American plate. The main cause of the rise of the Andes is the compression of the rim of the South American Plate due to the subduction of the Nazca Plate. In the south, the Andes share a boundary with the former Patagonia Terrane. To the west, the Andes end at the Pacific Ocean, from a geographical approach, the Andes are considered to have their western boundaries marked by the appearance of coastal lowlands and a less rugged topography.
The Andes Mountains contain large quantities of iron ore located in mountains within the range. The Andean orogen has a series of bends or oroclines, the Bolivian Orocline is a seaward concave bending in the coast of South America and the Andes Mountains at about 18° S. At this point the orientation of the Andes turns from Northwest in Peru to South in Chile, the Andean segment north and south of the orocline have been rotated 15° to 20° counter clockwise and clockwise respectively. The Bolivian Orocline area overlaps with the area of maximum width of the Altiplano Plateau, the specific point at 18° S where the coastline bends is known as the Arica Elbow
A land snail is any of the numerous species of snail that live on land, as opposed to sea snails and freshwater snails. Land snail is the name for terrestrial gastropod mollusks that have shells. The majority of land snails are pulmonates and that is, they have a lung and breathe air. A minority however belong to more ancient lineages where their anatomy includes a gill. Many of these land snails live in habitats or microhabitats that are sometimes damp or wet. Land snails have a muscular foot, they use mucus to enable them to crawl over rough surfaces. Like other mollusks, land snails have a mantle, and they have one or two pairs of tentacles on their head and their internal anatomy includes a radula and a primitive brain. In terms of reproduction, the majority of land snails are hermaphrodite, tiny snails hatch out of the egg with a small shell in place, and the shell grows spirally as the soft parts gradually increase in size. Most land snails have shells that are right-handed in their coiling, Land snails move by gliding along on their muscular foot, which is lubricated with mucus and covered with epithelial cilia.
This motion is powered by succeeding waves of contractions that move down the ventral of the foot. This muscular action is visible when a snail is crawling on the glass of a window or aquarium. Snails move at a low speed. Snails secrete mucus externally to keep their bodies from drying out. The mucus that land snails secrete with the leaves a slime trail behind them. Snails have a mantle, a layer of tissue which covers all of the internal organs as they are grouped together in the visceral mass. The mantle extends outward in flaps which reach to the edge of the shell and in some cases can cover the shell, the mantle is attached to the shell, and creates the shell and makes shell growth possible by secretion. A lack of calcium, or low pH in their surroundings, can result in thin, usually a snail can repair damage to its shell over time if its living conditions improve, but severe damage can be fatal. When retracted into their shells, many snails with gills are able to protect themselves with a door-like anatomical structure called an operculum, Land snails range greatly in size
Paleoclimatology is the study of changes in climate taken on the scale of the entire history of Earth. It uses the records to determine the past states of the Earths various climate regions and he noted that the loess deposits at Timaru in the South Island recorded changes in climate, he called the loess a climate register. Paleoclimatologists employ a variety of techniques to deduce ancient climates. Mountain glaciers and the polar ice caps/ice sheets provide much data in paleoclimatology, ice-coring projects in the ice caps of Greenland and Antarctica have yielded data going back several hundred thousand years, over 800,000 years in the case of the EPICA project. Air trapped within fallen snow becomes encased in tiny bubbles as the snow is compressed into ice in the glacier under the weight of years snow. The trapped air has proven a valuable source for direct measurement of the composition of air from the time the ice was formed. Layering can be observed because of seasonal pauses in ice accumulation and can be used to establish chronology, changes in the layering thickness can be used to determine changes in precipitation or temperature.
Oxygen-18 quantity changes in ice layers represent changes in ocean surface temperature. Water molecules containing the heavier O-18 evaporate at a higher temperature than water molecules containing the normal Oxygen-16 isotope, the ratio of O-18 to O-16 will be higher as temperature increases. It depends on factors such as the waters salinity. Various cycles in those isotope ratios have been detected, pollen has been observed in the ice cores and can be used to understand which plants were present as the layer formed. Pollen is produced in abundance and its distribution is well understood. A pollen count for a layer can be produced by observing the total amount of pollen categorized by type in a controlled sample of that layer. Changes in plant frequency over time can be plotted through statistical analysis of pollen counts in the core, knowing which plants were present leads to an understanding of precipitation and temperature, and types of fauna present. Palynology includes the study of pollen for these purposes, volcanic ash is contained in some layers, and can be used to establish the time of the layers formation.
Each volcanic event distributed ash with a set of properties. Establishing the ashs source will establish a range of time to associate with layer of ice, climatic information can be obtained through an understanding of changes in tree growth. Generally, trees respond to changes in climatic variables by speeding up or slowing down growth, different species, respond to changes in climatic variables in different ways
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes that shape it. Geologists usually study geology, although backgrounds in physics, biology, field work is an important component of geology, although many subdisciplines incorporate laboratory work. Some geologists work in the mining business searching for metals and they are in the forefront of natural hazards and disasters prevention and mitigation, studying natural hazards such as earthquakes, volcanic activity, weather storms. Their studies are used to warn the public of the occurrence of these events. Geologists are important contributors to climate change discussions, james Hutton is often viewed as the first modern geologist. In 1785 he presented a paper entitled Theory of the Earth to the Royal Society of Edinburgh, Hutton published a two-volume version of his ideas in 1795. The first geological map of the U. S. was produced in 1809 by William Maclure, in 1807, Maclure commenced the self-imposed task of making a geological survey of the United States.
Almost every state in the Union was traversed and mapped by him and this antedates William Smiths geological map of England by six years, although it was constructed using a different classification of rocks. Sir Charles Lyell first published his famous book, Principles of Geology and this book, which influenced the thought of Charles Darwin, successfully promoted the doctrine of uniformitarianism. This theory states that slow geological processes have occurred throughout the Earths history and are still occurring today, in contrast, catastrophism is the theory that Earths features formed in single, catastrophic events and remained unchanged thereafter. Though Hutton believed in uniformitarianism, the idea was not widely accepted at the time, most geologists need skills in GIS and other mapping techniques. Geology students often spend portions of the year, especially the summer though sometimes during a January term, geologists may concentrate their studies or research in one or more of the following disciplines, the study of dating based on tree ring patterns.
Economic geology, the study of ore genesis, and the mechanisms of ore creation, the applied branch deals with the study of the chemical makeup and behaviour of rocks, and the study of the behaviour of their minerals. Geochronology, the study of isotope geology specifically toward determining the date within the past of rock formation, metamorphism and geological events. Geomorphology, the study of landforms and the processes that create them Hydrogeology, igneous petrology, the study of igneous processes such as igneous differentiation, fractional crystallization and volcanological phenomena. Isotope geology, the case of the composition of rocks to determine the processes of rock. Metamorphic petrology, the study of the effects of metamorphism on minerals, marine geology, the study of the seafloor, involves geophysical, geochemical and paleontological investigations of the ocean floor and coastal margins. Marine geology has strong ties to physical oceanography and plate tectonics, palaeoclimatology, the application of geological science to determine the climatic conditions present in the Earths atmosphere within the Earths history
Radiocarbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed by Willard Libby in the late 1940s, Libby received the Nobel Prize for his work in 1960. The radiocarbon dating method is based on the fact that radiocarbon is constantly being created in the atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting radiocarbon combines with oxygen to form radioactive carbon dioxide. When the animal or plant dies, it stops exchanging carbon with its environment, and from that point onwards the amount of 14C it contains begins to decrease as the 14C undergoes radioactive decay. Measuring the amount of 14C in a sample from a plant or animal such as a piece of wood or a fragment of bone provides information that can be used to calculate when the animal or plant died. The idea behind radiocarbon dating is straightforward, but years of work were required to develop the technique to the point where accurate dates could be obtained.
Research has been ongoing since the 1960s to determine what the proportion of 14C in the atmosphere has been over the past fifty thousand years. The resulting data, in the form of a curve, is now used to convert a given measurement of radiocarbon in a sample into an estimate of the samples calendar age. Other corrections must be made to account for the proportion of 14C in different types of organisms, additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s. Conversely, nuclear testing increased the amount of 14C in the atmosphere, measurement of radiocarbon was originally done by beta-counting devices, which counted the amount of beta radiation emitted by decaying 14C atoms in a sample. The development of dating has had a profound impact on archaeology. In addition to permitting more accurate dating within archaeological sites than previous methods, histories of archaeology often refer to its impact as the radiocarbon revolution.
Radiocarbon dating has allowed key transitions in prehistory to be dated, such as the end of the last ice age, and they synthesized 14C using the laboratorys cyclotron accelerator and soon discovered that the atoms half-life was far longer than had been previously thought. This was followed by a prediction by Serge A. Korff, employed at the Franklin Institute in Philadelphia and it had previously been thought that 14C would be more likely to be created by deuterons interacting with 13C. At some time during World War II, Willard Libby, who was at Berkeley, learned of Korffs research, in 1945, Libby moved to the University of Chicago where he began his work on radiocarbon dating. He published a paper in 1946 in which he proposed that the carbon in living matter might include 14C as well as non-radioactive carbon, by contrast, methane created from petroleum showed no radiocarbon activity because of its age. The results were summarized in a paper in Science in 1947, Libby and James Arnold proceeded to test the radiocarbon dating theory by analyzing samples with known ages
Soacha is considered a borough of Bogotá, but officially it is an autonomous municipality of the department of Cundinamarca. It has an important industrial zone and is home to mostly working-class families, Soacha borders Bojacá and Mosquera to the north, Sibaté and Pasca to the south, to the east the capital Bogotá and to the west Granada and San Antonio del Tequendama. With a population of 522,442 inhabitants, Soacha is Bogotas most populous suburb, the name Soacha is derived from the Chibcha words Súa, name of Sun god Sué, and chá which means man, Man of the Sun. The original name Suecha has been changed to Soacha over time, the zipa of Bacatá ruled over Soacha. Modern Soacha was founded on 15th of August,1600 and it gained national notoriety after the presidential candidate Luis Carlos Galán was assassinated on August 18,1989 while visiting the city during his presidential campaign. Also during 1989, the bombing of Avianca Flight 203 happened in Soacha, the bombing was planned by Cartel de Medellin leader Pablo Escobar, who intended to murder presidential candidate Cesar Gaviria, who was supposed to be on board.
Gaviria had decided not to fly and instead went on to become President of Colombia, in 2008, the false positives scandal broke when 22 men from Soacha who had been recruited for work were found dead several hundreds of miles away. They had been killed by the military and presented to authorities as guerrilla fighters killed in battle, similar cases have since appeared all over the country. Ciudad Verde is a development project for the middle class residents of Soacha with housing, parks. The project started in 2010 and is scheduled to be finished at the end of 2016, walter Pedraza, professional cyclist Website of the city council
A ceramic is an inorganic, non-metallic, solid material comprising metal, non-metal or metalloid atoms primarily held in ionic and covalent bonds. This article gives an overview of ceramic materials from the point of view of materials science, the crystallinity of ceramic materials ranges from highly oriented to semi-crystalline and often completely amorphous. Most often, fired ceramics are either vitrified or semi-vitrified as is the case with earthenware, varying crystallinity and electron consumption in the ionic and covalent bonds cause most ceramic materials to be good thermal and electrical insulators. With such a range of possible options for the composition/structure of a ceramic, the breadth of the subject is vast. Many composites, such as fiberglass and carbon fiber, while containing ceramic materials, are not considered to be part of the ceramic family. The earliest ceramics made by humans were pottery objects or figurines made from clay, either by itself or mixed with materials like silica, sintered.
Later ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, ceramics now include domestic and building products, as well as a wide range of ceramic art. In the 20th century, new materials were developed for use in advanced ceramic engineering. The word ceramic comes from the Greek word κεραμικός, of pottery or for pottery, from κέραμος, potters clay, the earliest known mention of the root ceram- is the Mycenaean Greek ke-ra-me-we, workers of ceramics, written in Linear B syllabic script. The word ceramic may be used as an adjective to describe a material, product or process, or it may be used as a noun, either singular, or, more commonly, as the plural noun ceramics. A ceramic material is an inorganic, non-metallic, often crystalline oxide, nitride or carbide material, some elements, such as carbon or silicon, may be considered ceramics. Ceramic materials are brittle, strong in compression, weak in shearing and they withstand chemical erosion that occurs in other materials subjected to acidic or caustic environments.
Ceramics generally can withstand high temperatures, such as temperatures that range from 1,000 °C to 1,600 °C. Glass is often not considered a ceramic because of its amorphous character. However, glassmaking involves several steps of the process and its mechanical properties are similar to ceramic materials. Traditional ceramic raw materials include minerals such as kaolinite, whereas more recent materials include aluminium oxide. The modern ceramic materials, which are classified as advanced ceramics, include silicon carbide, both are valued for their abrasion resistance, and hence find use in applications such as the wear plates of crushing equipment in mining operations. Advanced ceramics are used in the medicine, electronics industries. Crystalline ceramic materials are not amenable to a range of processing
In archaeology, rock art is human-made markings placed on natural stone, it is largely synonymous with parietal art. A global phenomenon, rock art is found in many diverse regions of the world. It has been produced in many contexts throughout history, although the majority of rock art that has been ethnographically recorded has been produced as a part of ritual. Such artworks are often divided into three forms, which are carved into the surface, which are painted onto the surface. The oldest known rock art dates from the Upper Palaeolithic period, having found in Europe, Asia. Archaeologists studying these artworks believe that they likely had magico-religious significance, Rock art continues to be of importance to indigenous peoples in various parts of the world, who view them as both sacred items and significant components of their cultural patrimony. Such archaeological sites are significant sources of cultural tourism, and have been utilised in popular culture for their aesthetic qualities.
Normally found in cultures, a rock relief or rock-cut relief is a relief sculpture carved on solid or living rock such as a cliff. They are a category of art, and sometimes found in conjunction with rock-cut architecture. However, they tend to be omitted in most works on rock art, a few such works exploit the natural contours of the rock and use them to define an image, but they do not amount to man-made reliefs. Rock reliefs have been made in many cultures, and were important in the art of the Ancient Near East. Rock reliefs are generally large, as they need to be to make an impact in the open air. Most have figures that are over life-size, and in many the figures are multiples of life-size, the vertical relief is most common, but reliefs on essentially horizontal surfaces are found. The term typically excludes relief carvings inside caves, whether natural or themselves man-made, natural rock formations made into statues or other sculpture in the round, most famously at the Great Sphinx of Giza, are usually excluded.
Reliefs on large boulders left in their location, like the Hittite İmamkullu relief, are likely to be included. The term rock art appears in the literature as early as the 1940s. It has described as rock carvings, rock drawings, rock engravings, rock inscriptions, rock paintings, rock pictures. The defining characteristic of rock art is that it is placed on natural rock surfaces, as such, rock art is a form of landscape art, and includes designs that have been placed on boulder and cliff faces, cave walls and ceilings, and on the ground surface
Colombia, officially the Republic of Colombia, is a transcontinental country largely situated in the northwest of South America, with territories in Central America. Colombia shares a border to the northwest with Panama, to the east with Venezuela and Brazil and to the south with Ecuador and it shares its maritime limits with Costa Rica, Honduras, Jamaica and the Dominican Republic. It is a unitary, constitutional republic comprising thirty-two departments, the territory of what is now Colombia was originally inhabited by indigenous peoples including the Muisca, the Quimbaya and the Tairona. The Spanish arrived in 1499 and initiated a period of conquest and colonization ultimately creating the Viceroyalty of New Granada, independence from Spain was won in 1819, but by 1830 the Gran Colombia Federation was dissolved. What is now Colombia and Panama emerged as the Republic of New Granada, the new nation experimented with federalism as the Granadine Confederation, and the United States of Colombia, before the Republic of Colombia was finally declared in 1886.
Since the 1960s the country has suffered from an asymmetric low-intensity armed conflict, Colombia is one of the most ethnically and linguistically diverse countries in the world, and thereby possesses a rich cultural heritage. Cultural diversity has influenced by Colombias varied geography. The urban centres are located in the highlands of the Andes mountains. Colombian territory encompasses Amazon rainforest, tropical grassland and both Caribbean and Pacific coastlines, ecologically, it is one of the worlds 17 megadiverse countries, and the most densely biodiverse of these per square kilometer. Colombia is a power and a regional actor with the fourth-largest economy in Latin America, is part of the CIVETS group of six leading emerging markets and is an accessing member to the OECD. Colombia has an economy with macroeconomic stability and favorable growth prospects in the long run. The name Colombia is derived from the last name of Christopher Columbus and it was conceived by the Venezuelan revolutionary Francisco de Miranda as a reference to all the New World, but especially to those portions under Spanish and Portuguese rule.
The name was adopted by the Republic of Colombia of 1819. When Venezuela and Cundinamarca came to exist as independent states, New Granada officially changed its name in 1858 to the Granadine Confederation. In 1863 the name was changed, this time to United States of Colombia. To refer to country, the Colombian government uses the terms Colombia. Owing to its location, the present territory of Colombia was a corridor of early human migration from Mesoamerica, the oldest archaeological finds are from the Pubenza and El Totumo sites in the Magdalena Valley 100 km southwest of Bogotá. These sites date from the Paleoindian period, at Puerto Hormiga and other sites, traces from the Archaic Period have been found