219 résultats pour "similar"
- Two communities with different languages, Flemish, similar to Dutch, and Walloons, similar to French, share the territory.
- Dragon Dragon, a legendary reptilian monster similar in form to a crocodile and usually represented as having wings, huge claws, and a fiery breath.
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Algas - ciencias de la naturaleza.
Con excepción de las cianobacterias, que también han recibido el nombre de algas verdeazuladas, las algas están formadas por células eucariotas —es decir el interior de lacélula está organizado en orgánulos separados por una membrana, entre los que se encuentran el núcleo y las mitocondrias. Las cianobacterias son organismos procariotas,es decir organismos unicelulares bastante simples que carecen de núcleo. Sin embargo, como su actual nombre indica, las cianobacterias tienen características sim...
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Parkinson Disease.
III SYMPTOMS Parkinson disease most notably affects motor control (muscle activity). The disease progresses differently for each individual—symptoms develop swiftly in some peopleand slowly in others. Some Parkinson patients may develop problems that affect their intellect or ability to reason, or they may suffer from depression or anxiety. A Motor Control Problems Doctors look for the presence of four principal symptoms in patients they suspect may have Parkinson disease. Tremor (the involun...
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Venus (planet) - astronomy.
level winds circle the planet at 360 km/h (225 mph), making a complete rotation in only four days. These winds are said to super-rotate because they travel muchfaster than the rotation of the planet itself. These high-speed winds cover the planet completely, blowing toward the west at virtually every latitude from equator topole. The motions of descending probes, however, have shown that the bulk of Venus’s tremendously dense atmosphere, closer to the planet’s surface, is almoststagnant. From th...
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Dinosaur - biology.
The behavior of dinosaurs was governed by their metabolism and by their central nervous system. The dinosaurs’ metabolism—the internal activities that supply thebody’s energy needs—affected their activity level. It is unclear whether dinosaurs were purely endothermic (warm-blooded), like modern mammals, or ectothermic (cold-blooded), like modern reptiles. Endotherms regulate their body temperature internally by means of their metabolism, rather than by using the temperature oftheir surroundin...
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Mars (planet) - astronomy.
The Martian core is probably much like Earth’s, consisting mostly of iron, with a small amount of nickel. If other light elements, particularly sulfur, exist there as well, thecore may be larger than presently thought. From studying Earth’s magnetic field and core, scientists theorize that the motions of the liquid rock in Earth’s core generateits magnetic field. Mars does not have a significant magnetic field, so scientists believe that Mars’s core is probably solid. However, spacecraft data in...
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Evolución humana - ciencias de la naturaleza.
Los cambios genéticos pueden mejorar la capacidad de los organismos para sobrevivir, reproducirse y, en animales, criar a su descendencia. Este proceso se denominaadaptación. Los progenitores transmiten mutaciones genéticas adaptativas a su descendencia y finalmente estos cambios se generalizan en una población —un grupo de organismos de la misma especie que comparten un hábitat local particular. Existen numerosos factores que pueden favorecer nuevas adaptaciones, pero los cambios delentorno d...
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Molecule - chemistry.
attracted to the negatively charged electrons between them. The electrons belong to the molecule as a whole. However, each hydrogen atom now has a complete outershell of two electrons. The formula H 2 describes a hydrogen molecule, a discrete unit. When a molecule contains just two atoms, such as the hydrogen molecule does, it is called a diatomic molecule. Some atoms can form covalent bonds with more than one other atom and thus create a larger molecule. Atoms form molecules with covalent bo...
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Evolución humana - ciencias de la naturaleza.
Los cambios genéticos pueden mejorar la capacidad de los organismos para sobrevivir, reproducirse y, en animales, criar a su descendencia. Este proceso se denominaadaptación. Los progenitores transmiten mutaciones genéticas adaptativas a su descendencia y finalmente estos cambios se generalizan en una población —un grupo de organismos de la misma especie que comparten un hábitat local particular. Existen numerosos factores que pueden favorecer nuevas adaptaciones, pero los cambios delentorno d...
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Eye.
I
INTRODUCTION
Eye, light-sensitive organ of vision in animals. The eyes of
Several structures, not parts of the eyeball, contribute to the protection of the eye. The most important of these are the eyelids, two folds of skin and tissue, upper andlower, that can be closed by means of muscles to form a protective covering over the eyeball against excessive light and mechanical injury. The eyelashes, a fringe ofshort hairs growing on the edge of either eyelid, act as a screen to keep dust particles and insects out of the eyes when the eyelids are partly closed. Inside the...
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Jupiter (planet) - astronomy.
Beneath the supercritical fluid zone, the pressure reaches 3 million Earth atmospheres. At this depth, the atoms collide so frequently and violently that the hydrogenatoms are ionized—that is, the negatively charged electrons are stripped away from the positively charged protons of the hydrogen nuclei. This ionization results in asea of electrically charged particles that resembles a liquid metal and gives rise to Jupiter’s magnetic field. This liquid metallic hydrogen zone is 30,000 to 40,000 k...
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Learning.
B1 Acquisition The acquisition phase is the initial learning of the conditioned response—for example, the dog learning to salivate at the sound of the bell. Several factors can affect the speed of conditioning during the acquisition phase. The most important factors are the order and timing of the stimuli. Conditioning occurs most quickly when theconditioned stimulus (the bell) precedes the unconditioned stimulus (the food) by about half a second. Conditioning takes longer and the response is...
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Human Evolution.
Strepsirhines are the most primitive types of living primates. The last common ancestors of strepsirhines and other mammals—creatures similar to tree shrews andclassified as Plesiadapiformes—evolved at least 65 million years ago. The earliest primates evolved by about 55 million years ago, and fossil species similar to lemursevolved during the Eocene Epoch (about 55 million to 38 million years ago). Strepsirhines share all of the basic characteristics of primates, although their brains are notpa...
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Comparative Anatomy.
In comparing two species, anatomists have to be careful to differentiate between homologous structures, which are ones that have evolved from a shared ancestor, andanalogous structures, which have developed from different origins. Homologous structures are built on the same underlying plan. A human arm, a bat’s wing, and awhale’s flipper look quite different from the outside, but the bones inside reveal that these limbs all have the same basic structure. Analogous structures, by contrast,often l...
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Collectibles and Collecting.
common blond and thus commands a higher price. If there are different variations to a collectible, the least common one is usually worth more. Often there areinteresting stories behind rarities, such as the highly sought-after 1909 Honus Wagner baseball card. At that time tobacco companies manufactured and distributedbaseball cards, and when the antitobacco Wagner complained, his card was pulled from production. Very few copies in good condition have ever been found. C Age Age is often an indic...
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Anfibio - ciencias de la naturaleza.
las ranas, que tienen una cavidad media que transmite las vibraciones desde la membrana timpánica al oído interno. Las ranas y los sapos también utilizan su sentido deloído para comunicarse unas con otras. Además, tanto las ranas macho como las hembra, utilizan las cuerdas vocales presentes en la laringe para producir sonidos, cuyaprincipal función es atraer a la pareja para reproducirse; también realizan sonidos en las disputas territoriales. Las salamandras, las cecilias y algunas ranas carece...
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Cancer (medicine).
unable to repair the DNA damage, p53 instructs the cell to undergo programmed cell death, or apoptosis , putting a stop to runaway cell division before it starts. Programmed cell death is a normal part of cell life and is tightly controlled by many genes, primarily p53. In a cancerous cell, one or more mutations prevent these genes from doing their jobs. When mutated, p53 allows a cell to continue to divide, even with damaged DNA.This can lead to additional mutations in proto-oncogenes or tumor...
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Inorganic Chemistry - chemistry.
two electrically charged plates (positively charged top plate and negatively charged bottom plate). By measuring the difference in how fast these electron-laden oildrops fell when the metal plates were charged and uncharged, Millikan was able to calculate the total charge on each oil drop. Because each measurement was a wholenumber multiple of -1.60 × 10 -19 coulombs, Millikan concluded this was the charge carried by a single electron. Using Thomson’s electron charge-to-mass ratio, Millikan then...
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Electric Motors and Generators.
the armature. It is often desirable to generate as high a voltage as possible, and rotating armatures are not practical in such applications because of the possibility of sparkingbetween brushes and slip rings and the danger of mechanical failures that might cause short circuits. Alternators are therefore constructed with a stationary armaturewithin which revolves a rotor composed of a number of field magnets. The principle of operation is exactly the same as that of the AC generator described,...
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Computer Memory.
been created, information can be retrieved but not changed. Newer technologies allow ROMs to be semi-permanent—that is, the information can be changed, but ittakes several seconds to make the change. For example, a FLASH memory acts like a ROM because values remain stored in memory, but the values can be changed. C External Memory External memory can generally be classified as either magnetic or optical, or a combination called magneto-optical. A magnetic storage device, such as a computer'shar...
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Intelligence.
education. Teachers had no way of knowing which of the “slow” students had true learning problems and which simply had behavioral problems or poor prior education.In 1904 the French Ministry of Public Instruction asked Binet and others to develop a method to objectively identify children who would have difficulty with formaleducation. Objectivity was important so that conclusions about a child’s potential for learning would not be influenced by any biases of the examiner. The governmenthoped tha...
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Automobile Racing.
beginning in 1906 at Le Mans it came to refer to the principal F1 auto race in a given nation, except in the United States, where the term continues to be used lessdiscriminately. After the end of World War I in 1918, when automobile racing blossomed internationally, a series of GP races in several nations became reserved for F1competition, and an annual GP calendar was developed consisting of national races, such as the French Grand Prix and the British Grand Prix. An annual award calledthe Wor...
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Human Evolution - biology.
classified as Plesiadapiformes—evolved at least 65 million years ago. The earliest primates evolved by about 55 million years ago, and fossil species similar to lemursevolved during the Eocene Epoch (about 55 million to 38 million years ago). Strepsirhines share all of the basic characteristics of primates, although their brains are notparticularly large or complex and they have a more elaborate and sensitive olfactory system (sense of smell) than do other primates. B Haplorhines B1 Tarsiers T...
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Atom - chemistry.
Atoms have several properties that help distinguish one type of atom from another and determine how atoms change under certain conditions. A Atomic Number Each element has a unique number of protons in its atoms. This number is called the atomic number (abbreviated Z). Because atoms are normally electrically neutral,the atomic number also specifies how many electrons an atom will have. The number of electrons, in turn, determines many of the chemical and physical properties ofthe atom. The ligh...
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Skiing.
Safety is very important to all skiers, and all Alpine resorts have a ski patrol. The ski patrol’s responsibility is to take care of injured skiers, to mark hazardous spots ontrails, to make sure that trails are in good condition before opening them, and, at times, to act as traffic police in congested areas. Skiers are also responsible for takingtheir own safety into consideration, as well as that of others. Anyone who participates in the sport should be aware of the Skier’s Responsibility Code...
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Planetary Science - astronomy.
III ORIGINS AND COMPOSITIONS OF PLANETS Astronomers believe that planetary systems are formed of elemental materials that were created in the interiors of giant stars. Some of this material comes from giantstars that shed material into space as they age. Most of the matter to form planets, however, comes from stars that explode as supernovas and spread debris enrichedwith the heavier chemical elements into space. According to the currently accepted views, the most likely first stage in the evo...
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Rana - ciencias de la naturaleza.
Rana excavadoraLas patas cortas y fuertes de esta rana son adecuadas para cavar. Se entierra en la arena del desierto del sur de Australia para eludirel calor y queda sumida en un estado similar a la hibernación. Otras lo hacen para esconderse o tender emboscadas. Muchas tienen elhocico afilado o dedos espatulados, que les ayudan a cavar.Kathie Atkinson/Oxford Scientific Films La mayoría de las ranas, en especial los machos, emiten sonidos. Al expulsar el aire de los pulmones, éste hace vibrar l...
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Serpiente - ciencias de la naturaleza.
Serpiente engullendoBBC Worldwide Americas, Inc. El cuerpo largo y delgado de las serpientes contiene numerosas vértebras —nunca menos de 100 y a veces más de 300—, cada una de ellas con un par de costillas, las dosprimeras conectadas a la cabeza. El esqueleto es de estructura ligera y presenta características específicas que permiten una gran libertad de movimientos. Las piezas delcráneo gozan de gran movilidad y pueden dislocarse en varias direcciones, lo que permite a la serpiente tragar pres...
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Geología - ciencias de la naturaleza.
marcas dejadas por las garras de un oso gigante.F. Gohier/Photo Researchers, Inc. Los pueblos antiguos consideraban muchas características y procesos geológicos como obra de los dioses. Observaban el entorno natural con miedo y admiración, comoalgo peligroso y misterioso. Así, los antiguos sumerios, babilonios y otros pueblos, pese a realizar descubrimientos notables en matemáticas y astronomía, erraban en susinvestigaciones geológicas al personificar los procesos geológicos. Las leyendas irland...
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Asteroid - astronomy.
Asteroids of the S type, related to the stony iron meteorites, make up about 15 percent of the total population of asteroids that can be seen from Earth. Much rarer arethe M-type objects, corresponding in composition to the meteorites known as “irons.” These objects are made up of an iron-nickel alloy and may represent the cores ofbodies that were large enough to differentiate into layers and to melt deep inside. Their rocky outer layers may have been removed by impacts with other asteroids . A...
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Prints and Printmaking
I
INTRODUCTION
Prints and Printmaking, pictorial images that can be inked onto paper, and the art of creating and reproducing them.
Bewick’s The SkylarkBritish engraver Thomas Bewick’s The Skylark is part of his History of British Birds (2 vols., 1797 and 1804). Bewick wasthe first artist to demonstrate the full potential of wood engraving and is renowned for his fine natural history illustrations.Each illustration shows some of the bird’s natural habitat.Folio Society, London/Bridgeman Art Library, London/New York Historically, the wood engraving was chiefly used for illustrations in magazines and books. It is similar to th...
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How similar and different are you from your parents?
didn’t want to give their opinion about that but I could have easily guessed that they would not have accepted some of these sections. It was clear that I should have chosen sciences , like my brother and sister did . Do our personalities differ? Probably, to a certain extent they do, but not essentially. If being different means having different tastes in music or ways to spend free time, then we are different, since we have entirely opposite views on music, films and pastimes. For...
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Vertebrate - biology.
E Reptiles Compared to amphibians, reptiles are much more fully adapted to life on land. They have scaly, waterproof skin, and they either give birth to live young or lay eggs withwaterproof shells. There are about 7,000 species alive today, including snakes, alligators, and turtles. During the age of the dinosaurs, about 230 million to 65 millionyears ago, reptiles outnumbered all other land vertebrates put together. F Birds Birds evolved from flightless reptiles but underwent some major chan...
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Photosynthesis - biology.
P680 in Photosystem II is now electron deficient because it has donated electrons to P700 in Photosystem I. P680 electrons are replenished by the water that has beenabsorbed by the plant roots and transported to the chloroplasts in the leaves. The movement of electrons in Photosystems I and II and the action of an enzyme split thewater into oxygen, hydrogen ions, and electrons. The electrons from water flow to Photosystem II, replacing the electrons lost by P680. Some of the hydrogen ions maybe...
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Drug Dependence.
these drugs develops rapidly, no withdrawal syndrome is apparent when they are discontinued. Phencyclidine, or PCP, known popularly by such names as “angel dust” and “rocket fuel,” has no medical purpose for humans but is occasionally used by veterinarians asan anesthetic and sedative for animals. It became a common drug of abuse in the late 1970s, and is considered a menace because it can easily be synthesized. Itseffects differ from those of other hallucinogens. LSD, for example, produces deta...
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Biodiversidad - ciencias de la naturaleza.
Las áreas ricas en especies endémicas pueden ser lugares de especiación activa o de refugio de especies muy antiguas; sea cual sea su interés teórico, es importante parala gestión práctica de la biodiversidad identificar estas áreas discretas con proporciones elevadas de endemismos. Por definición, las especies endémicas de un lugardeterminado no se encuentran en ningún otro. Cuanto menor es el área de endemismo, mayor es el riesgo de que las especies endémicas sufran cambios de población deorig...
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Arab Music
I
INTRODUCTION
Umm Kulthum
Egyptian singer Umm Kulthum was revered throughout Egypt, North Africa, and the Near East for her powerful voice and
improvisational skill.
The rhythmic structure of Arab music is similarly complex. Rhythmic patterns have up to 48 beats and typically include several downbeats (called dums ) as well as upbeats (called taks) and silences, or rests. To grasp a rhythmic mode, the listener must hear a relatively long pattern. Moreover, the performers do not simply play the pattern; they elaborate upon and ornament it. Often the pattern is recognizable by the arrangement of downbeats. The Rhythm in Arab Music illustration demonstratesa...
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Primate - biology.
The primate order includes a handful of species that live entirely on meat (carnivores) and also a few that are strict vegetarians (herbivores), but it is composed chieflyof animals that have varied diets (omnivores). The carnivorous primates are the four species of tarsiers, which live in Southeast Asia. Using their long back legs, thesepocket-sized nocturnal hunters leap on their prey, pinning it down with their hands and then killing it with their needle-sharp teeth. Tarsiers primarily eat in...
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Shark - biology.
Sharks have two-chambered hearts that are relatively small compared to the rest of their bodies. Blood flows from the heart to the gills, where it collects oxygen fromwater and then distributes it to the other organs and tissues. The small heart produces weak blood pressure, and many sharks must swim continuously to create themuscular contractions needed to circulate blood throughout their bodies. Most sharks are cold-blooded—that is, they do not generate heat by digesting food. Instead, the bod...
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Mythology.
Across cultures, mythologies tend to describe similar characters. A common character is the trickster. The trickster is recklessly bold and even immoral, but through hisinventiveness he often helps human beings. In Greek mythology, Hermes (best known as the messenger of the gods) was a famous trickster. In one version of acharacteristic tale, Hermes, while still an infant, stole the cattle of his half-brother Apollo. To avoid leaving a trail that could be followed, Hermes made shoes from thebark...
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Comet - astronomy.
may exceed the planet Jupiter in size, however. Observations from telescopes on Earth and in space indicate that most of the gases in the coma and tail of a comet are fragmentary molecules, or radicals, of the mostcommon elements in space: hydrogen, carbon, nitrogen, and oxygen. The radicals, for example, of CH, NH, and OH may be broken away from the stable molecules CH 4 (methane), NH 3 (ammonia), and H 2O (water), which may exist as ices or more complex, very cold compounds in the nucleus. Al...
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Cell (biology) - biology.
proteins, or other proteins required by the cell. While relatively simple in construction, prokaryotic cells display extremely complex activity. They have a greater range of biochemical reactions than those found in theirlarger relatives, the eukaryotic cells. The extraordinary biochemical diversity of prokaryotic cells is manifested in the wide-ranging lifestyles of the archaebacteria andthe bacteria, whose habitats include polar ice, deserts, and hydrothermal vents—deep regions of the ocean un...
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South Africa - country.
The major soil zones are conditioned largely by climatic factors. In the semiarid north and west, soils are alkaline and poorly developed. In the southern part of WesternCape Province, rain falls mostly in the winter months, and soils there form slowly and are generally thin and immature. The moderate temperatures and summer rainfallof the High Veld and eastern coastal areas create conditions for more productive organic decomposition, leading to dark, fertile soils, or chernozems, similar to tho...
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Devoir d'anglais correction
particular occasion you lacked the tiny bit that would have made the differenceor, as in the given example, you gave the wrong answer to one essential question.The document suggests that in order to take no chances when preparing for a job interview, you should stick asclosely as possible to the skills and attributes mentioned in the job advertisement. If you don't get the job, youshould be prepared to accept it and move on.Being well aware of the qualities required for a position is vital, but...
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Tiburón - ciencias de la naturaleza.
de algunas especies grandes miden más de 1 m de longitud y son nadadores veloces que se alimentan de las mismas presas que los adultos. En muchos casos, las críasnacen en zonas protegidas próximas a la costa, lejos de los machos. Los tiburones ayunan durante largos periodos en la estación de reproducción y se mantienenrecurriendo a las grandes reservas de lípidos almacenadas en el hígado. Así evitan devorarse los unos a los otros, así como a las crías. 4 SENTIDOS Y ALIMENTACIÓN Tiburones cazand...
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Geología - ciencias de la naturaleza.
marcas dejadas por las garras de un oso gigante.F. Gohier/Photo Researchers, Inc. Los pueblos antiguos consideraban muchas características y procesos geológicos como obra de los dioses. Observaban el entorno natural con miedo y admiración, comoalgo peligroso y misterioso. Así, los antiguos sumerios, babilonios y otros pueblos, pese a realizar descubrimientos notables en matemáticas y astronomía, erraban en susinvestigaciones geológicas al personificar los procesos geológicos. Las leyendas irland...
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Técnicas de grabado - artes.
2.2 Grabado en hueco Es lo contrario del grabado en relieve; en lugar de sobresalir de la superficie, las líneas de la imagen están incisas en una plancha de metal. Hay dos tipos básicos degrabado en hueco: se puede grabar el dibujo en la plancha utilizando diversos instrumentos puntiagudos llamados agujas, bruñidores, raedores y graneadores, o se puederebajar en la plancha por la corrosión de los ácidos. Gracias a estos diferentes métodos el grabado en hueco permite conseguir una amplia gama d...
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Crustáceos - ciencias de la naturaleza.
El cefalotórax suele tener apéndices, que se emplean en la locomoción y la respiración. El caparazón sirve a menudo como cubierta protectora de las branquias, que formanparte de las extremidades. Algunas extremidades pueden formar pinzas (quelas). Los apéndices abdominales pueden usarse para la locomoción, pero con frecuenciadesempeñan otras funciones, como la respiración, y tienden a tener un tamaño reducido. El telson, una parte de la cola en la que va el ano, se usa en algunas ocasionespara l...
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Tectónica de placas - ciencias de la naturaleza.
continentales señalada por el famoso geólogo vienés Eduard Suess, hacia 1880. Reconoció un ‘tipo atlántico’ de margen, identificado por el truncado abrupto de antiguascadenas montañosas y por estructuras hendidas, y un ‘tipo pacífico’, marcado por montañas dispuestas en cordilleras paralelas, por líneas de volcanes y por terremotosfrecuentes. Para muchos geólogos, las costas de tipo pacífico parecen estar localizadas donde los geosinclinales se deforman y se elevan para formar montañas. 3 EXPANS...