User:Fev/sandbox

The Geography of the population is closely related to the demographics in terms of content, methods and goals , but with an important difference in approach as the study population demographics from the standpoint of quantitative and statistical while the Geography of the population , also called some vecesDemogeografía 1 study it from the point of spatial or geographically. The conception of demography as a statistical science is reported in Dewey decimal classification of libraries, which appears demographics as part of statistical works , whereas the geography of the population is between the geographic themes. You could consider demographics as an auxiliary science of geography of the population, taking into account that the most important as demographic concepts happens censuses, civil registration, population growth, birth rates (and mortality , infant mortality, illiteracy, etc. . ) are used in order to analyze them geographically to determine similarities and differences between different areas or geographic regions. The Geography of the population is a relatively new discipline, although quite old is unprecedented in the eighteenth century and even earlier. The writings of geography during the classical period of Greece and made ​​reference to the peoples who inhabited the already large land area of its inhabitants. Chroniclers also undertook to erect a kind of Indian population censuses in order to establish the divisions of land and indigenous parcels : the richest parcels were the largest number of Indians had. And in the seventeenth century were numerous geographical encyclopedias that only served to incorporate various data, whether of the population of each area, region or city , or the characteristics of the population : such is the case of the masterpiece of Antonio José Cavanilles , lasObservaciones on the Natural History, Geography, Population and Fruits of the Kingdom of Valencia , and in the nineteenth century , works of Humboldt, Madoz2 and many others. The idea that the richest country was the most populous continued well into the nineteenth century, as seen in the Gaceta de Madrid, the precursor of the Official State Gazette ( BOE) when referring to the people of Cuba , emphasizing his superiority to certain states , by the fact that Cuba had a higher population density in one or two people per square mile , to such States3 In the field of demography had written works that can be considered as the initiator of the discipline , especially the most important work of Malthus , Essay on the Principle of Population , but could not be considered as works developed the field of population geography. Could be cited as an exception to the rule of the two trials E. G. Ravenstein in England called Laws of Migration (4 ), in which comparatively examines geographic patterns of migration (from where it migrates more , what are the areas that receive more immigrants are, what sex that dominates migration short and long , where they come from as many immigrants as the transport distance , etc). As we see, these tests can be classified as purely geographical or demogeográficos and emphasizing more geographical movements of population statistics of the population itself. But it was not until the twentieth century when John Wilbur Zelinsky and will appear I. Geography studies of people with the same name, including Clarke. The Clarke himself (5) has been identified as the most important in the field of Geography of the population of Zelinsky (6 ) which indicates a significant initial literature to develop the study of the initial field work. The human population has never been evenly distributed over the earth's surface, first, because the environment does not offer the same amount of natural resources and therefore, the same living conditions everywhere, and secondly because technological progress , also not equally distributed over the earth's surface tends to cause an increasing concentration of population in urban areas. That is why the people of primitive societies, with a lower level of technology, is distributed more evenly over the territory where they live in the most advanced societies. And the same can be said for the past primitive societies : groups of hunters and gatherers of old, for example, need a certain space where to get food, so they had a need for much better distributed in the territory and control the number of inhabitants and growth. In fact, in many animal species and in some primitive societies, the struggle for territory is a form of population control. It is the thesis of some demographers who has been raised in the book of Robert Ardrey territorial The imperative and refers to the need of the animals and, by extension , people in primitive societies divide the territory to obtain the resources needed for subsistence. This process of dispersion of the population, increasingly rare with the increasing scarcity of sparsely populated areas is being repeated in the occupation of new lands for agricultural purposes , as the occupants have to divide the land to cultivate their plots. The process of occupation of Brazilian territory with the frontiersmen, especially during the nineteenth and twentieth centuries , was a progressive movement to occupy new lands that could be identified as such. Population density indicates the statistical relationship between the number of people or people who constitute the population of an area and the land in that area, expressed in number of people per unit area ( km ², square miles , hectares, etc. . ) and usually measured in inhabitants per km ² (hab . / km ²). Population densities as countries tend to misrepresent how is distributed the population on Earth's surface, as some very large countries (such as China, Brazil, USA , Canada and others ) have , with densely populated regions , other with a very low density , as can be seen by comparing the two maps included in the article. You could say that a comparison between the two maps can emerge a more accurate view of how the world's population is distributed. And if we see this distribution in large-scale maps of small countries we can further refine the concept of population density, a concept that depends , like most concepts in geography , geographic or cartographic map scale. In the first map offers a view of the distribution of the most successful population, since these densities are referred to small areas or provinces of each country. However in the second map, population densities refer to the entire country , which often mask the true population concentrations. This shows that the density in India is quite high but if the set is represented in the first map, most of the population is located to the north of the country, which is the broad valley of the Ganges. The same can be said of China, whose highest proportion of inhabitants is located in the lower reaches of the Yangtze River and the Yellow River or Hoang Ho, ie , in the eastern part of the country, while the west ( Inner Mongolia , Tibet ) is very sparsely populated. Main article: Population Density It is the population that is set in an area of ​​recent population engaged in agriculture pioneer. In this way a process of dispersion of the population, at least in initial stages occurs. As their only source of income is the cultivation of the soil, it is necessary at the outset, are equitably the ground, whereby the population, at least at first, usually tend not to concentration. However, with increasing population and agricultural production, this concentration is almost inevitable. This is the general idea put into relief by Ester Boserup, for whom technological change in agriculture occurs upon reaching a critical point demográfica7 rate density which not only increases the concentration of population , but the technical development, increased production and, above all , the diversification of the economy, with the initiation and growth of industrial and service companies. The sparse population is a form of rural habitat, and is the field of study of rural geography. It typically is the urban population, ie the population living in cities and has been going through a process of concentration of the population that gives rise to the highest densities in the world today, especially in the countries or states that are composed of a single city like Singapore , Monaco or the old Hong Kong. It is the field of study of urban geography. The concentration of population is a process that has also been occurring in rural areas, as they grow the towns and villages with the development of services , schools and other works of urban type , which make it beneficial pooling of inhabitants , while still engaging in agricultural work. This process of progressive concentration is very easily seen in the image of the town of Alta Brena included as an illustration of dispersed habitat although it has a high density and each year, with a smaller proportion of population engaged in agricultural tasks. the process of migration from rural to big cities, known as rural exodus , population has contributed , first , to the depopulation of many rural towns and mainly , on the other, a growing agglomeration in the most populated cities , reaching in many cases settlement formation uncontrolled housing ( favelas , ranches, shantytowns , etc. . ) and crowded housing. The increasing concentration of urban population has been taking two factors : each of the cities atracciónpor : availability ( education, health, urban , leisure and recreation, etc. ) services , larger and more diverse sources of work, especially for women , and other rural rejection ( lack of resources , lack of jobs , especially for women , lack or inadequate educational, health and social assistance, etc. ), both acting simultaneously. Numerous studies on the concentration of population come to be noted that this concentration is increasing in almost everyone. It is true that what is known as the central city, central or original core of many cities is decreasing population today, but this is always done in exchange for growth in the area of influence of these cities, which many sometimes known as the metropolitan area. The main consequences of the unequal distribution of the population may be mentioned the following : • Imbalance in investment, which comes to speed , in turn , concentration , leading to a vicious circle: a larger population requires more investments and these , in turn , fail to attract new immigrants. • Increased growth in absolute terms, the areas that are already densely populated , resulting in problems with regard to the provision of the required services, which are much higher in areas that are already over populated. For example, build a school in a crowded city would be a much greater investment in rural areas , the high cost of urban land , among many other factors. • Overcrowding, with its consequences: promiscuity, crime, marginalization , growth of informal housing neighborhoods , etc. . • Significant increase in pollution per unit area in areas where the population is concentrated in the form creciente8 • Impaired population ratio - resources. This alteration is a growing social inequality between the most and the less fortunate, between city and countryside, between slums and housing developments. However, all the problems of urban-type solution would eventually be developed if appropriate urban cultural coherent economic policy, rural , and y. Issues related to population growth are highly controversial. Some people think that people should continue to grow in accordance with the mandate bíblicoCreced and multiply, while others argue tesisantinatalistas, programs favoring birth control , family planning , the legalization of abortion , etc. . And these theses have come to develop in entire countries. As Masseyeff points out : In this issue, more than any other, optimists ( favoring pro - natalist thesis) and pessimists (anti - natalist ) are irreconciliables.9 • Population growth has always been an ongoing process, with some interruptions ( the time of the Black Death, periods of general war, etc. . ). As is logical, slow population growth until the twentieth century was due to mortality was very high, as was always the threat of the four horsemen of the apocalypse ( famine, war, pestilence and death ) , as told in the novel by Vicente Blasco Ibáñez.10 Although the plot of the novel focuses on the period of the First World War , when millions of people died and how many people in the world fell for a few years , the film Vincente Minnelli was acclimated in the Second World War , when nearly 70 million people died mainly in Europe and Asia. • But it was in the second half of the twentieth century, ie , after the second world war , when population growth reached enormous proportions , due to the process known as control mortality for the development of antibiotics , advances in medicine , the treatment of many infectious diseases and many other developments. This process of rapid population growth was called population explosion. However, the same technology has been developing what has come to cause an incipient decline in the birth rate but increasing is known as the demographic transition, a term used and defined by Warren S. Thompson in 1929 and collected in a Spanish translation published by The Medical Press Mexicana in 1969.11 The mortality declined dramatically while the birth rate remained high. But as we have seen, this process of demographic transition was offset in time by a declining birth rate has returned to balance the population growth process at a lower level. Birth rate the number of births is called for one year in a particular country or place. This figure refers to the birth rate in absolute terms. However, to enable comparisons to be made ​​in this sense we speak of the birth rate, which is obtained by calculating the number of births per hundred inhabitants of the population in the same year (sometimes per thousand inhabitants ). This means that a birth rate of 15 per thousand up to 15 births per 1000 people living in the country or place in Reference (15 º / º º or 1.5 %). Mortality in a particular country or place is the total number of deaths in that country or place in the course of a year deaths. It is an absolute fact. To compare several mortality data from different countries relative mortality data were used, ie, mortality rates , which allow you to quickly visualize the differences in mortality data in different places. The population growth of a country in a year is set each year by adding births and subtracting the number of deaths. They are therefore growth was once known as vegetative growth (gross growth). To this figure must be added when the net migration is positive ( mayorinmigración that emigration) and subtract it when negative ( greater emigration to immigration). The total figure would become the absolute population growth in a country (net population growth). The composition of the population according to certain demographic characteristics is of fundamental importance in the field of Geography of the population and that the information in this regard is crucial for planning and political and administrative organization of any country. These features may indicate the following : • composition of the population by age and sex. This composition is represented by a horizontal bar chart representing in the x-axis, absolute data or percentages of the total population , male (left ) and women (right ). The y-axis represents the different age groups, generally of 5 to 5 years ( 0 to 4, 5 to 9, 10 to 14 , etc. ). In a normal situation, This is a pyramid, so called population pyramid , and has the widest base ( no more children) and with increasingly narrow bars as it rises to the top ( older ages ). At the base there is always more boys than girls by the fact that the human species more males are born (about 102 or 103 boys for every 100 girls). But this situation is reversed from 60 to 65 years, that there are many more women than men by the longer life expectancy of the female population. • socio-professional composition of the workforce • Educational Composition In demography and population geography, migration is called the movement or displacement of human beings on the earth's surface. The term migration in this area has two meanings: a broad, including all types of movements of humans, and other , more restricted , it only takes into account those movements involving a change of residence of those performing. Thus, in its broadest sense also include tilting movements of population between the home and the workplace. In population geography, is given more importance to the concept of the term restricted while swings are a subject studied in urban geography. Any migration process involves two concepts : • Emigration, which is the output of people from one country, place or region to settle in another country, place or region. Migration implies a negative estimate of the level of a person's life and their family environment and a perception that to settle elsewhere will increase its economic, social and other perspectives or, at least , that their hopes for a better life will be paid in the future. The migrants are those who leave the country, both individually and collectively migration process. • Immigration is the arrival in a country of people from other country or place. They are called immigrants to people who come from a country elsewhere. The most important way from the nineteenth century to the present day migration is known as rural exodus, which is the massive displacement of population from rural to urban , millions of people move annually from rural to urban areas across countries of the world (especially in developing countries ) in search of better living conditions and , above all, greater employment opportunities. --Fev 23:25, 6 February 2014 (UTC)
 * The Geography of population is a branch of human geography that studies the structures and spatial patterns of human population demographic phenomena and processes of change in those phenomena over time. These demographic phenomena can be noted : • ( geographical ) Spatial distribution of humans. • Population growth both globally and regionally or locally. • Structures of the population ( by age and sex composition, socio- professional population , educational structure , composition etc . ) • Population Mobility ( Migration) in space and over time

Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the world's largest rivers. When overland flow occurs on tilled fields, it can result in a muddy flood where sediments are picked up by run off and carried as suspended matter or bed load. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, ice, debris, or beaver dams. Due to the Earth's rotation movement, floods are much more frequent along the left bank of most rivers in the Northern Hemisphere, and along the right bank in the Southern Hemisphere. Mississipi floods are a good example of this fact (i. e. Hickman, Tiptonville, Columbus (Ky), Cairo, Paducah, Memphis, Vicksburg, Natchez, Baton Rouge) for the Northern Hemisphere; and floods in Australia (1956 Murray River flood) with most towns along the right bank of the Murray River (Colignan, Iraak, Mannum, Murray Bridge, Mildura, Nangiloc, Red Cliffs, Renmark, Wentworth and many others), in the Southern Hemisphere. The Earth's rotation movement is also the reason for natural river banks being asymmetric, being the right bank higher in the Northern Hemisphere and lower than the left one in the Southern Hemisphere.
 * Riverine flooding:

Slow-rising floods most commonly occur in large rivers with large catchment areas. The increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, or tropical cyclones. However, large rivers may have rapid flooding events in areas with dry climate, since they have large basins but small river channels and rainfall can be very intense in smaller areas of those basins.

Rapid flooding events, including flash floods, more often occur on smaller rivers, rivers with steep valleys, rivers that flow for much of their length over impermeable terrain, or normally-dry channels. The cause may be localized convective precipitation (intense thunderstorms) or sudden release from an upstream impoundment created behind a dam, landslide, or glacier. In one instance, a flash flood killed 8 people enjoying the water on a Sunday afternoon at a popular waterfall in a narrow canyon. Without any observed rainfall, the flow rate increased from about 50 to 1,500 cubic feet per second (1.4 to 42 m3/s) in just one minute.[5] Two larger floods occurred at the same site within a week, but no one was at the waterfall on those days. The deadly flood resulted from a thunderstorm over part of the drainage basin, where steep, bare rock slopes are common and the thin soil was already saturated.

Flash floods are the most common flood type in normally-dry channels in arid zones, known as arroyos in the southwest United States and many other names elsewhere. In that setting, the first flood water to arrive is depleted as it wets the sandy stream bed. The leading edge of the flood thus advances more slowly than later and higher flows. As a result, the rising limb of the hydrograph becomes ever quicker as the flood moves downstream, until the flow rate is so great that the depletion by wetting becomes insignificant.

Assymmetry of river basins
Due to the Earth's rotation movement, floods are much more frequent along the left bank of most rivers in the Northern Hemisphere, and along the right bank in the Southern Hemisphere. Mississippi floods are a good example of this fact (i. e. Hickman, Tiptonville, Columbus (Ky), Cairo, Paducah, Memphis, Vicksburg, Natchez, Baton Rouge) for the Northern Hemisphere; and floods in Australia (1956 Murray River flood) with most towns along the right bank of the Murray River (Colignan, Iraak, Mannum, Murray Bridge, Mildura, Nangiloc, Red Cliffs, Renmark, and Wentworth), in the Southern Hemisphere. The Earth's rotation movement is also the reason for natural river banks being asymmetric, being the right bank higher in the Northern Hemisphere and lower than the left one in the Southern Hemisphere. This fact is responsible of more frequent breaching events on the left margin of the river in the Northern Hemisphere and along the right bank in the Southern Hemisphere. Other differences between North and South Hemispheres regarding river dynamics are: − 	−
 * Meanders occur more often along the left bank of rivers in the Northern Hemisphere and along the right one in the Southern Hemisphere.
 * The same process happens to river capture, shifting river channels and river bank erosion.