A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. Lagoons are commonly divided into coastal lagoons and atoll lagoons and they have been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries, lagoons are common coastal features around many parts of the world. Lagoons can be man-made and used for treatment, as is the case for e. g. aerated lagoons. Lagoons are shallow, often elongated bodies of water separated from a body of water by a shallow or exposed shoal, coral reef. Some authorities include fresh water bodies in the definition of lagoon, the distinction between lagoon and estuary varies between authorities. Richard A. Davis Jr. restricts lagoon to bodies of water with little or no fresh water inflow, and little or no tidal flow, Davis does state that the terms lagoon and estuary are often loosely applied, even in scientific literature.
Timothy M. Kusky characterizes lagoons as normally being elongated parallel to the coast, while estuaries are usually drowned river valleys, coastal lagoons are classified as inland bodies of water. Many lagoons do not include lagoon in their common names, in England, The Fleet at Chesil Beach has been described as a lagoon. In Latin America, the term laguna in Spanish, which translates to. However, sometimes it is used to describe a full-sized lake, such as Laguna Catemaco in Mexico. The brackish water lagoon may be explicitly identified as a coastal lagoon. In Portuguese the same usage is found, lagoa may be a body of sea water. Lagoon is derived from the Italian laguna, which refers to the waters around Venice, Laguna is attested in English by at least 1612, and had been Anglicized to lagune by 1673. In 1697 William Dampier referred to a Lagune or Lake of Salt water on the coast of Mexico, captain James Cook described an island of Oval form with a Lagoon in the middle in 1769. Atoll lagoons form as coral reefs grow upwards while the islands that the reefs surround subside, unlike the lagoons that form shoreward of fringing reefs, atoll lagoons often contain some deep portions.
Coastal lagoons form along gently sloping coasts where barrier islands or reefs can develop off-shore, coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than 4 metres. Due to the slope of the coast, coastal lagoons are shallow
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate. The Mohs scale of hardness, based on scratch hardness comparison. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite, aragonite will change to calcite at 380–470 °C, and vaterite is even less stable. Calcite is derived from the German Calcit, a term coined in the 19th century from the Latin word for lime and it is thus etymologically related to chalk. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, prisms, or various scalenohedra. Calcite exhibits several twinning types adding to the variety of observed forms and it may occur as fibrous, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form and its fracture is conchoidal, but difficult to obtain. It has a defining Mohs hardness of 3, a gravity of 2.71.
Color is white or none, though shades of gray, orange, green, violet, calcite is transparent to opaque and may occasionally show phosphorescence or fluorescence. A transparent variety called Iceland spar is used for optical purposes, acute scalenohedral crystals are sometimes referred to as dogtooth spar while the rhombohedral form is sometimes referred to as nailhead spar. Single calcite crystals display an optical property called birefringence and this strong birefringence causes objects viewed through a clear piece of calcite to appear doubled. The birefringent effect was first described by the Danish scientist Rasmus Bartholin in 1669, at a wavelength of ~590 nm calcite has ordinary and extraordinary refractive indices of 1.658 and 1.486, respectively. Between 190 and 1700 nm, the refractive index varies roughly between 1.9 and 1.5, while the extraordinary refractive index varies between 1.6 and 1.4. Calcite, like most carbonates, will dissolve with most forms of acid, calcite can be either dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH, and dissolved ion concentrations.
Although calcite is fairly insoluble in water, acidity can cause dissolution of calcite. Ambient carbon dioxide, due to its acidity, has a slight solubilizing effect on calcite, calcite exhibits an unusual characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures. On a landscape scale, continued dissolution of calcium carbonate-rich rocks can lead to the expansion and eventual collapse of cave systems, high-grade optical calcite was used in World War II for gun sights, specifically in bomb sights and anti-aircraft weaponry
In mathematics and chemistry, a space group is the symmetry group of a configuration in space, usually in three dimensions. In three dimensions, there are 219 distinct types, or 230 if chiral copies are considered distinct, Space groups are studied in dimensions other than 3 where they are sometimes called Bieberbach groups, and are discrete cocompact groups of isometries of an oriented Euclidean space. In crystallography, space groups are called the crystallographic or Fedorov groups. A definitive source regarding 3-dimensional space groups is the International Tables for Crystallography, in 1879 Leonhard Sohncke listed the 65 space groups whose elements preserve the orientation. More accurately, he listed 66 groups, but Fedorov and Schönflies both noticed that two of them were really the same, the space groups in 3 dimensions were first enumerated by Fedorov, and shortly afterwards were independently enumerated by Schönflies. The correct list of 230 space groups was found by 1892 during correspondence between Fedorov and Schönflies, burckhardt describes the history of the discovery of the space groups in detail.
The space groups in three dimensions are made from combinations of the 32 crystallographic point groups with the 14 Bravais lattices, the combination of all these symmetry operations results in a total of 230 different space groups describing all possible crystal symmetries. The elements of the space group fixing a point of space are rotations, the identity element, the translations form a normal abelian subgroup of rank 3, called the Bravais lattice. There are 14 possible types of Bravais lattice, the quotient of the space group by the Bravais lattice is a finite group which is one of the 32 possible point groups. Translation is defined as the moves from one point to another point. A glide plane is a reflection in a plane, followed by a parallel with that plane. This is noted by a, b or c, depending on which axis the glide is along. There is the n glide, which is a glide along the half of a diagonal of a face, and the d glide, the latter is called the diamond glide plane as it features in the diamond structure.
In 17 space groups, due to the centering of the cell, the glides occur in two directions simultaneously, i. e. the same glide plane can be called b or c, a or b. For example, group Abm2 could be called Acm2, group Ccca could be called Cccb, in 1992, it was suggested to use symbol e for such planes. The symbols for five groups have been modified, A screw axis is a rotation about an axis. These are noted by a number, n, to describe the degree of rotation, the degree of translation is added as a subscript showing how far along the axis the translation is, as a portion of the parallel lattice vector. So,21 is a rotation followed by a translation of 1/2 of the lattice vector
In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. Ordered structures occur from the nature of the constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter. The smallest group of particles in the material that constitutes the pattern is the unit cell of the structure. The unit cell completely defines the symmetry and structure of the crystal lattice. The repeating patterns are said to be located at the points of the Bravais lattice, the lengths of the principal axes, or edges, of the unit cell and the angles between them are the lattice constants, called lattice parameters. The symmetry properties of the crystal are described by the concept of space groups, all possible symmetric arrangements of particles in three-dimensional space may be described by the 230 space groups. The crystal structure and symmetry play a role in determining many physical properties, such as cleavage, electronic band structure.
The crystal structure of a material can be described in terms of its unit cell, the unit cell is a box containing one or more atoms arranged in three dimensions. The unit cells stacked in three-dimensional space describe the arrangement of atoms of the crystal. Commonly, atomic positions are represented in terms of fractional coordinates, the atom positions within the unit cell can be calculated through application of symmetry operations to the asymmetric unit. The asymmetric unit refers to the smallest possible occupation of space within the unit cell and this does not, however imply that the entirety of the asymmetric unit must lie within the boundaries of the unit cell. Symmetric transformations of atom positions are calculated from the group of the crystal structure. Vectors and planes in a lattice are described by the three-value Miller index notation. It uses the indices ℓ, m, and n as directional parameters, which are separated by 90°, by definition, the syntax denotes a plane that intercepts the three points a1/ℓ, a2/m, and a3/n, or some multiple thereof.
That is, the Miller indices are proportional to the inverses of the intercepts of the plane with the unit cell, if one or more of the indices is zero, it means that the planes do not intersect that axis. A plane containing a coordinate axis is translated so that it no longer contains that axis before its Miller indices are determined, the Miller indices for a plane are integers with no common factors. Negative indices are indicated with horizontal bars, as in, in an orthogonal coordinate system for a cubic cell, the Miller indices of a plane are the Cartesian components of a vector normal to the plane. Likewise, the planes are geometric planes linking nodes
Hexagonal crystal family
In crystallography, the hexagonal crystal family is one of the 6 crystal families. In the hexagonal family, the crystal is described by a right rhombic prism unit cell with two equal axes, an included angle of 120° and a height perpendicular to the two base axes. There are 52 space groups associated with it, which are exactly those whose Bravais lattice is either hexagonal or rhombohedral, the hexagonal crystal family consists of two lattice systems and rhombohedral. Each lattice system consists of one Bravais lattice, there are 3 lattice points per unit cell in total and the lattice is non-primitive. The Bravais lattices in the hexagonal crystal family can be described by rhombohedral axes, the unit cell is a rhombohedron. This is a cell with parameters a = b = c, α = β = γ ≠ 90°. In practice, the description is more commonly used because it is easier to deal with a coordinate system with two 90° angles. However, the axes are often shown in textbooks because this cell reveals 3m symmetry of crystal lattice.
However, such a description is rarely used, the hexagonal crystal family consists of two crystal systems and hexagonal. A crystal system is a set of point groups in which the point groups themselves, the trigonal crystal system consists of the 5 point groups that have a single three-fold rotation axis. The crystal structures of alpha-quartz in the example are described by two of those 18 space groups associated with the hexagonal lattice system. The hexagonal crystal system consists of the seven point groups such that all their groups have the hexagonal lattice as underlying lattice. Graphite is an example of a crystal that crystallizes in the crystal system. Note that the atom in the center of the HCP unit cell in the hexagonal lattice system does not appear in the unit cell of the hexagonal lattice. It is part of the two atom motif associated with each point in the underlying lattice. The trigonal crystal system is the crystal system whose point groups have more than one lattice system associated with their space groups.
The 5 point groups in this system are listed below, with their international number and notation, their space groups in name. The point groups in this system are listed below, followed by their representations in Hermann–Mauguin or international notation and Schoenflies notation
Carl Linnaeus, known after his ennoblement as Carl von Linné, was a Swedish botanist and zoologist, who formalised the modern system of naming organisms called binomial nomenclature. He is known by the father of modern taxonomy. Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus, Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his education at Uppsala University. He lived abroad between 1735 and 1738, where he studied and published a first edition of his Systema Naturae in the Netherlands and he returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on journeys through Sweden to find and classify plants. In the 1750s and 1760s, he continued to collect and classify animals and minerals, at the time of his death, he was one of the most acclaimed scientists in Europe. The philosopher Jean-Jacques Rousseau sent him the message, Tell him I know no man on earth. The German writer Johann Wolfgang von Goethe wrote, With the exception of Shakespeare and Spinoza, Swedish author August Strindberg wrote, Linnaeus was in reality a poet who happened to become a naturalist.
Among other compliments, Linnaeus has been called Princeps botanicorum, The Pliny of the North and he is considered as one of the founders of modern ecology. In botany, the abbreviation used to indicate Linnaeus as the authority for species names is L. In older publications, sometimes the abbreviation Linn. is found, Linnæus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus Ingemarsson and Christina Brodersonia and his siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, and Emerentia Linnæa. One of a line of peasants and priests, Nils was an amateur botanist, a Lutheran minister. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius, a year after Linnæus birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curates house, even in his early years, Linnæus seemed to have a liking for plants, flowers in particular.
Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus, soon Linnæus was given his own patch of earth where he could grow plants
In mineralogy, crystal habit is the characteristic external shape of an individual crystal or crystal group. A single crystals habit is a description of its shape and its crystallographic forms. Recognizing the habit may help in identifying a mineral, when the faces are well-developed due to uncrowded growth a crystal is called euhedral, one with partially developed faces is subhedral, and one with undeveloped crystal faces is called anhedral. The long axis of a quartz crystal typically has a six-sided prismatic habit with parallel opposite faces. Aggregates can be formed of individual crystals with euhedral to anhedral grains, the arrangement of crystals within the aggregate can be characteristic of certain minerals. For example, minerals used for asbestos insulation often grow in a fibrous habit, the terms used by mineralogists to report crystal habits describe the typical appearance of an ideal mineral. Recognizing the habit can aid in identification as some habits are characteristic, most minerals, however, do not display ideal habits due to conditions during crystallization.
Minerals belonging to the crystal system do not necessarily exhibit the same habit. Some habits of a mineral are unique to its variety and locality, For example, while most sapphires form elongate barrel-shaped crystals, the latter habit is seen only in ruby. Sapphire and ruby are both varieties of the mineral, corundum. Some minerals may replace other existing minerals while preserving the originals habit, a classic example is tigers eye quartz, crocidolite asbestos replaced by silica. While quartz typically forms prismatic crystals, in tigers eye the original fibrous habit of crocidolite is preserved, the names of crystal habits are derived from, Predominant crystal faces. Abnormal grain growth Grain growth Crystallization
Iron is a chemical element with symbol Fe and atomic number 26. It is a metal in the first transition series and it is by mass the most common element on Earth, forming much of Earths outer and inner core. It is the fourth most common element in the Earths crust, like the other group 8 elements and osmium, iron exists in a wide range of oxidation states, −2 to +6, although +2 and +3 are the most common. Elemental iron occurs in meteoroids and other low oxygen environments, but is reactive to oxygen, fresh iron surfaces appear lustrous silvery-gray, but oxidize in normal air to give hydrated iron oxides, commonly known as rust. Unlike the metals that form passivating oxide layers, iron oxides occupy more volume than the metal and thus flake off, Iron metal has been used since ancient times, although copper alloys, which have lower melting temperatures, were used even earlier in human history. Pure iron is soft, but is unobtainable by smelting because it is significantly hardened and strengthened by impurities, in particular carbon. A certain proportion of carbon steel, which may be up to 1000 times harder than pure iron.
Crude iron metal is produced in blast furnaces, where ore is reduced by coke to pig iron, further refinement with oxygen reduces the carbon content to the correct proportion to make steel. Steels and iron alloys formed with metals are by far the most common industrial metals because they have a great range of desirable properties. Iron chemical compounds have many uses, Iron oxide mixed with aluminium powder can be ignited to create a thermite reaction, used in welding and purifying ores. Iron forms binary compounds with the halogens and the chalcogens, among its organometallic compounds is ferrocene, the first sandwich compound discovered. Iron plays an important role in biology, forming complexes with oxygen in hemoglobin and myoglobin. Iron is the metal at the site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants. A human male of average height has about 4 grams of iron in his body and this iron is distributed throughout the body in hemoglobin, muscles, bone marrow, blood proteins, ferritin and transport in plasma.
The mechanical properties of iron and its alloys can be evaluated using a variety of tests, including the Brinell test, Rockwell test, the data on iron is so consistent that it is often used to calibrate measurements or to compare tests. An increase in the content will cause a significant increase in the hardness. Maximum hardness of 65 Rc is achieved with a 0. 6% carbon content, because of the softness of iron, it is much easier to work with than its heavier congeners ruthenium and osmium. Because of its significance for planetary cores, the properties of iron at high pressures and temperatures have been studied extensively
Natural history is the research and study of organisms including animals and plants in their environment, leaning more towards observational than experimental methods of study. It encompasses scientific research but is not limited to it, with articles nowadays more often published in magazines than in academic journals. Grouped among the sciences, natural history is the systematic study of any category of natural objects or organisms. That is a broad designation in a world filled with many narrowly focused disciplines. For example, geobiology has a strong multi-disciplinary nature combining scientists, a person who studies natural history is known as a naturalist or natural historian. The English term natural history is a translation of the Latin historia naturalis and its meaning has narrowed progressively with time, while the meaning of the related term nature has widened. In antiquity, it covered essentially anything connected with nature or which used materials drawn from nature. For example, Pliny the Elders encyclopedia of this title, published circa 77 to 79 AD, covers astronomy, geography and his technology and superstition as well as animals and plants.
Medieval European academics considered knowledge to have two divisions, the humanities and divinity, with science studied largely through texts rather than observation or experiment. In modern terms, natural philosophy roughly corresponded to modern physics and chemistry, natural history had been encouraged by practical motives, such as Linnaeus aspiration to improve the economic condition of Sweden. Similarly, the Industrial Revolution prompted the development of geology to help find useful mineral deposits, the astronomer, William Herschel was a natural historian. Instead of working with plants or minerals he worked with the stars and he spent his time building telescopes to see the stars and the rest of the time watching the stars. In the beginning, he believed there to be a known as a nebulae. Herschel can be considered a natural historian because he observed the natural world, in the process he made charts of all the stars and kept records of all that he saw. S. Wilcove and T. Eisner, The close observation of organisms—their origins, their evolution, their behavior and it encompasses changes in internal states insofar as they pertain to what organisms do.
Some definitions go further, focusing on observation of organisms in their environment. Bartholomew, A student of history, or a naturalist, studies the world by observing plants. A common thread in many definitions of natural history is the inclusion of a component, as seen in a recent definition by H. W. Greene
Lead is a chemical element with atomic number 82 and symbol Pb. When freshly cut, it is bluish-white, it tarnishes to a dull gray upon exposure to air and it is a soft and heavy metal with a density exceeding that of most common materials. Lead has the second-highest atomic number of the stable elements. Lead is a relatively unreactive post-transition metal and its weak metallic character is illustrated by its amphoteric nature and tendency to form covalent bonds. Compounds of lead are found in the +2 oxidation state. Exceptions are mostly limited to organolead compounds, like the lighter members of the group, lead exhibits a tendency to bond to itself, it can form chains and polyhedral structures. Lead is easily extracted from its ores and was known to people in Western Asia. A principal ore of lead, often bears silver, Lead production declined after the fall of Rome and did not reach comparable levels again until the Industrial Revolution. Nowadays, global production of lead is about ten million tonnes annually, Lead has several properties that make it useful, high density, low melting point and relative inertness to oxidation.
In the late 19th century, lead was recognized as poisonous, Lead is a neurotoxin that accumulates in soft tissues and bones, damaging the nervous system and causing brain disorders and, in mammals, blood disorders. A lead atom has 82 electrons, arranged in a configuration of 4f145d106s26p2. The combined first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, leads upper neighbor in group 14. This is unusual since ionization energies generally fall going down a group as an elements outer electrons become more distant from the nucleus, the similarity is caused by the lanthanide contraction—the decrease in element radii from lanthanum to lutetium, and the relatively small radii of the elements after hafnium. The contraction is due to shielding of the nucleus by the lanthanide 4f electrons. The combined first four ionization energies of lead exceed those of tin, for this reason lead, unlike tin, mostly forms compounds in which it has an oxidation state of +2, rather than +4.
Relativistic effects, which become particularly prominent at the bottom of the periodic table, as a result, the 6s electrons of lead become reluctant to participate in bonding, a phenomenon called the inert pair effect. A related outcome is that the distance between nearest atoms in crystalline lead is unusually long, the lighter group 14 elements form stable or metastable allotropes having the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp3 orbitals
Magnesite is a mineral with the chemical formula MgCO3. Mixed crystals of iron carbonate and magnesite possess a layered structure, manganese and nickel may occur in small amounts. Magnesite occurs as veins in and a product of ultramafic rocks, serpentinite. These magnesites often are cryptocrystalline and contain silica in the form of opal or chert, magnesite can be formed via talc carbonate metasomatism of peridotite and other ultramafic rocks. Magnesite is formed via carbonation of olivine in the presence of water and carbon dioxide at elevated temperatures, magnesite can be formed via the carbonation of magnesium serpentine via the following reaction,2 Mg3Si2O54 +3 CO2 → Mg3Si4O102 +3 MgCO3 +3 H2O. However, when performing this reaction in the laboratory, the form of magnesium carbonate will form at room temperature. This very observation led to the postulation of a barrier being involved in the low-temperature formation of anhydrous magnesium carbonate. Laboratory experiments with formamide, a liquid resembling water, have shown how no such dehydration barrier can be involved, the fundamental difficulty to nucleate anhydrous magnesium carbonate remains when using this non-aqueous solution.
Not cation dehydration, but rather the spatial configuration of carbonate anions creates the barrier in the nucleation of magnesite. Magnesite has been found in sediments and soils. Its low-temperature formation is known to require alternations between precipitation and dissolution intervals, magnesite was detected in meteorite ALH84001 and on planet Mars itself. Magnesite was identified on Mars using infra-red spectroscopy from satellite orbit, controversy still exists over the temperature of formation of this magnesite. Low-temperature formation has been suggested for the magnesite from the Mars derived ALH84001 meteorite, the low-temperature formation of magnesite might well be of significance toward large-scale carbon sequestration. Magnesium-rich olivine favors production of magnesite from peridotite, iron-rich olivine favors production of magnetite-magnesite-silica compositions. Magnesite can be formed by way of metasomatism in skarn deposits, in dolomitic limestones, associated with wollastonite and talc.
Similar to the production of lime, magnesite can be burned in the presence of charcoal to produce MgO, large quantities of magnesite are burnt to make magnesium oxide, an important refractory material used as a lining in blast furnaces and incinerators. Light burnt product generally refers to calcination commencing at 450 °C and proceeding to a limit of 900 °C - which results in good surface area. Above 900 °C, the material loses its reactive crystalline structure, magnesite can be used as a binder in flooring material
Rio de Janeiro
Rio de Janeiro, or simply Rio, is the second-most populous municipality in Brazil and the sixth-most populous in the Americas. The metropolis is anchor to the Rio de Janeiro metropolitan area, Rio de Janeiro is the capital of the state of Rio de Janeiro, Brazils third-most populous state. Part of the city has designated as a World Heritage Site, named Rio de Janeiro. Founded in 1565 by the Portuguese, the city was initially the seat of the Captaincy of Rio de Janeiro, later, in 1763, it became the capital of the State of Brazil, a state of the Portuguese Empire. Rio stayed the capital of the pluricontinental Lusitanian monarchy until 1822 and this is one of the few instances in history that the capital of a colonising country officially shifted to a city in one of its colonies. Rio de Janeiro has the second largest municipal GDP in the country, the home of many universities and institutes, it is the second-largest center of research and development in Brazil, accounting for 17% of national scientific output according to 2005 data.
The Maracanã Stadium held the finals of the 1950 and 2014 FIFA World Cups, the 2013 FIFA Confederations Cup, the city is divided into 33 administrative regions. Europeans first encountered Guanabara Bay on 1 January 1502, by a Portuguese expedition under explorer Gaspar de Lemos captain of a ship in Pedro Álvares Cabrals fleet, allegedly the Florentine explorer Amerigo Vespucci participated as observer at the invitation of King Manuel I in the same expedition. The region of Rio was inhabited by the Tupi, Botocudo, in 1555, one of the islands of Guanabara Bay, now called Villegagnon Island, was occupied by 500 French colonists under the French admiral Nicolas Durand de Villegaignon. Consequently, Villegagnon built Fort Coligny on the island when attempting to establish the France Antarctique colony, Rio de Janeiro was the name of Guanabara Bay. Until early in the 18th century, the city was threatened or invaded by several, mostly French and buccaneers, such as Jean-François Duclerc, on 27 January 1763, the colonial administration in Portuguese America was moved from Salvador to Rio de Janeiro.
The kingdoms capital was transferred to the city, thus, as there was no physical space or urban structure to accommodate hundreds of noblemen who arrived suddenly, many inhabitants were simply evicted from their homes. The first printed newspaper in Brazil, the Gazeta do Rio de Janeiro, from the colonial period until the first independent decades, Rio de Janeiro was a city of slaves. There was an influx of African slaves to Rio de Janeiro, in 1819. In 1840, the number of slaves reached 220,000 people, the Port of Rio de Janeiro was the largest port of slaves in America. As a political center of the country, Rio concentrated the political-partisan life of the Empire and it was the main stage of the abolitionist and republican movements in the last half of the 19th century. Rio continued as the capital of Brazil after 1889, when the monarchy was replaced by a republic, until the early years of the 20th century, the city was largely limited to the neighbourhood now known as the historic city centre, on the mouth of Guanabara Bay.
Expansion of the city to the north and south was facilitated by the consolidation and electrification of Rios streetcar transit system after 1905, though many thought that it was just campaign rhetoric, Kubitschek managed to have Brasília built, at great cost, by 1960