A dune is an accumulation of sand in the deserts that are generate by the wind so this is why they have this shapes,they are produced by the wind changes or because of the variation of the amount of sand.When the wind has a dominantdirection, the dunes have a C shape; the advance direction of the dunes is the factor that decides the huge. The small one are the one that go faster, the highest dunes are the one that are 4 or 6 meters. This kind of dunes and these movements you can see in Sechura desert (In Peru).

The movements of the dunes can cause big problems like: the invasion of villages, towns, roads, fields... the best way to control this invasions is to plant trees next and over the dune, other possibility is to spray materials like petrol or some used oils. The first village to do this was the town of villa Gesell in Bonaernse and rhe man who did this kind of experiments was Carlos Idaho Gesell in the Uruguay cost, nowdays cover by pinewoods. But in Spain there some examples too, like Barbate´s pinewood.

What would you do is you where in a village near a dune, and you know that in some moment the dune would invade your house?
This question was the principal one when in 19 century in Barbate the villagers has to plant pines covering a dune.

Earthquakes

The tectonics plates make up the Lithosphere that is the more superficial layer of the earth ,those plates are settled in the astenosphere, that is a liquid layer made up of a hot material; now I'm going to talk about three cities and I'm going to say my opiniof about which is the best one city to live in;

Tokio: Is one of the urban cities more importants of the planet, it has a smaller number of skyscrapers in comparation with other cities of its scale due to the earthquake risk,so the majority of its buildings don't have more than 10 floors;I think even if Tokio is a very well prepared city for a earthquake; I wouldn'r like to live there because it one of the places where more earthquakes happen!

S.Francisco:In 1906 a big earthquake was produced, it devasted S.Francisco , in 1989 another earthquake was produced that killed 250 persons! I neither would like to live there even if the buildings are safer than in toko and they have less probabillities for an earthquake to happen than in tokio

Malaga: In Spain the sismic risk is concentred in the limit between the Euroasiatic plate amd and the African plate , the last earthquake that caused catastrophic damages happened the 25 December in 1884 affecting Malaga and Granada; I would choose Malaga even if its not very well prepared to an earthquake is the place of the ones I've choosen that has less probabillities of an earthquake to happen.

Floods in Spain.

The flooding is one of the natural catastrophes that kill more people. In the XX century is calculated that there were 3.2 million people died because of this phenomenon. In Spain this is a social and economic problem, it happen especially in the Mediterranean zone and in the North.

The factors that cause this flooding are: excess of precipitation, melting of snow, breaking of dams and human activity. In Spain floods are also the natural catastrophe that causes more impact. The areas were floods more affect are: The North basin (principally in Pais Vasco). That’s because there use to be from time to time very much precipitations (450L/m2 in a day) the valleys are narrow and deep and the population is situated near the channels. Also in the Mediterranean area floods affect. The risk is high in places like Jucar’s banks, Murcia or Malaga and Granada. This is caused because of torrential rains (like 700L/m2 in a day), also helped the absence of trees and an easy erosion of the soil.

In conclusion, because of different causes the flooding is the natural phenomenon that more problems produce. In Spain it happens more often in the North and in the Mediterranean zone.

INCAS CIVILIZATION

The Incas civilization was the largest pre-Hispanic empire of south America when it was “discover” by the Spanish conquistadors in the 16th AD, the Incas civilization controlled all of the western part of the continent between Ecuador and Chile.
They were a warlike village who fundated a powerful empire.
The Inca’s capital was at Cusco, Peru.
The Inca civilization farmed cotton, potatoes, and corn and herder alpacas. They made up irrigated land systems and constructed crops on the slopes of the mountains.
The metallurgy of the gold and the copper increased its development, and the ceramic was decorated with human’s figures, animals, flowers...
They were distributed in clans, an extended family.
Their principal Gods were Viracocha, creator and son of the Sun and the Moon.
The towns, where they constructed great stones, were communicated by services of post office and very big roads, which crosses the Andes.

El doping en el deporte

Tomando como referencia las marcas deportivas alcanzadas en el alto rendimiento, día a día, se buscan nuevos métodos para tratar de superar dichas marcas. Una forma externa de influir en el rendimiento físico de un atleta ha sido mediante el consumo de sustancias prohibidas.
Esta sustancias, al ser ingeridas, provocan un aumento artificial de un rendimiento deportivo.
La administración o uso por parte de un atleta de cualquier sustancia estimulante denomina doping.
Uno de los principales avances de la lucha antidopaje es la relación de análisis de sangre para detectar la presencia de EPO, que es la sustancia que se usa habitualmente en deportes de resistencia como ciclismo, esquí, atletismo...
El análisis de orina es, sin embargo, el principal método de control antidopaje.
De esta forma, numerosos deportistas profesionales han sido sancionados por el consumo de dichas sustancias prohibidas como Maradona, Ben Jonson...

Aztec civilization

The Aztecs.

The Aztecs, that were a warrior civilization, were poblating the north of the actual Mexico. The empire, was deed by a three town confederation: Tenochtitlan, Texcoco and Tlacopan. The Aztec society was structured in tribus and they were divided in 4 society classes:

• The Priests, who were respected by all the people because fo the important religious belief.


• The noblemn who played an important role in theis civilization.


• The Free Men, who haven't enough resources and they were treated like so, and they constituted the mayority of the Aztec's society.


• Finally, the Slaves, who were war prisoners who hadn't been sacrified to the gods.

Aztec culture had rich and complex mythological and religious traditions. For europeans, the most striking element of the Aztec culture, was the practice of human sacrifice which was conducted thoroughout Mesoamerica prior to the spanish conquest. The Aztecs spoke classical Nahuatl.

They lived fo the corn grown and of taxes that they collected from the near towns. This civilization was conquered by Hernan Cortes in 1521 when Moctezuma II was the emperor.

On the image we can see the chinampas, a very effective method of cultivation of the Aztecs.

THE MAYA CIVILIZATION

The Maya civilization is probably the best known of Mesoamerica's classical civilizations .Born in the Yucatan Peninsula around 2600 B.C. their civilization spread to parts of what is now Mexico, Honduras, El Salvador, and most of Guatemala and Belice.

The mayas built huge religious pyramids and developed an important system of writing and a very advanced mathematics. Their astronomers calculated the exact period of the solar year and the lunar months, and they were also able to predict the eclipses.

They played a basketball variant which constitutes a religious and sport ceremony. When a player scored, he had the right to take the possesions of any of the people of the audience. The players, could only use the hips, elbows and ankles to control the ball.