The drums in hardcore music play loud and fast, often characterized by use of the double-bass pedal, particularly notable in the breakdowns.
Limestone
Limestone is a sedimentary rock, made up mostly of the mineral calcite, a form of calcium carbonate, CaCO.
The calcium carbonate is originally produced by living organisms. Later, some of it goes into solution in sea water. Limestone rocks include mainly organic remains and precipitated carbonate.
Limestone is about 10% of the total volume of all sedimentary rocks.
Limestones are mostly made of calcium carbonate. It is originally made by small photosynthetic protists like certain bacteria, coccolithophores, and algae. Then the carbonate gets used by various animals, like bivalves and the polyps which make coral reefs. They build their shells or framework out of CaCO crystals.
Carbonates are rocks formed from these sources, plus any CaCO which is precipitated out of solution. Some carbonate dissolves in the water. It gets precipitated when the physical condition of the water changes. For example, if the concentration of CaCO is high, then a temperature drop, or a pH (acidity) change, can cause precipitation.
Florida Bay, the shallow lagoon behind the Florida Keys, is a model for the conditions which produced limestones on the continental shelf. Of course, all the species were somewhat different then but, as an ecosystem, it is similar.
In Florida Bay there is a lot of a type of flowering plant called sea grass. There is also a lot of white, milky water full of calcium carbonate. This is mainly formed by "Melobesia", a small red alga which lives on the sea grass. Finally, the organisms produce huge amounts of slime, which is a polysaccharide. There is good reason to think the slime is produced by microorganisms to control the way their carbonate skeletons are formed. As a side-effect the slime limits the amount of carbonate which goes into solution.
Florida Bay is a flat platform which has laid down a huge amount of carbonate rock.
Many limestones contain fossils, and some are made up almost entirely of skeletal material. Chalk is ~99% coccoliths; Solnhofen limestone is famous for its animal fossils; and there are many shelly limestones from different periods. Limestone is not found much before the Cambrian period, because shelled animals had not yet evolved.
When limestone is heated to a high temperature, and squeezed at the base of a mountain, it recrystallizes into the metamorphic rock marble. Marbles are fairly dense, relatively easy to cut, or be shaped into blocks, and some forms are white in colour.
Limestone is hard enough to resist weathering but usually soft enough to be worked (cut and carved) by stonemasons. It is used for building material. Limestone, particularly Portland limestone, became popular in the 19th and 20th centuries for building things such as churches, banks and houses. However, acid rain does slowly erode limestone.
Limestone is used to make glass and cement. It is also used to make iron in a blast furnace, to remove impurities from the iron ore.
Root
The roots of a plant is the part that is usually buried in the soil. Roots are usually always under the soil, though–sometimes roots can be above the ground. This is called an aerial root.
Also, stems can sometimes be under the soil (potatoes, for example). Roots do not have leaves, and are different from stems inside.
Plants need their roots especially for three reasons: The roots take water and nutrients, a sort of food, from the soil. They also often store this food. And they fix the plants to the ground.
However, most plant roots do not work at their best unless they have help from fungi. The symbiosis between roots and fungus is known as mycorrhiza.
There are two sorts of root systems:
Some roots go very deep into the ground. One root that was found in Arizona, USA, was 60 m below the surface.
Roots are also very strong. Some tree roots can destroy stones. Roots are not green because the cells have no chlorophyll.
Roots grow through the whole life of the plant. They grow longer from the tip, adding cells to the end of each root. The root adds cells to their tips, and they grow fatter as they add cells around their tube-like bodies.
At the tip of each root, there is a small group of tough, dead, hard cells called the "root cap". The root cap is the strongest part of the root tip, and its job is to push its way through the dirt to look for moisture and nutrients and protect the plant.
Roots are usually found underground, but in some cases this is not so. In the rainforest, the air is warm and humid (it has a lot of water). Some rainforest plants, known as epiphytes, grow right on trees. Their roots hang down in the air or running into the moss growing on the trees. Many aerial roots, are used to receive water and nutrient intake directly from the air, from fog, dew or humid air.
Some trees have roots that are above the ground "and" underground. Mangrove trees have aerial roots (roots which come up into the air). They exchange gases with the atmosphere, just as leaves do. They are an adaptation to the poor level of oxygen in the waterlogged soil of the mangrove swamp.
The banyan tree has a root system that is underground, but it also has roots that start in its branches and grow down towards the ground. These roots not only take in water and nutrients from the soil, but they also help to support the long branches of the banyan tree. Because of this extra support, banyan tree branches can be really long. A banyantree in Lahaina, Maui, which was planted in 1873 by a man named William Owen Smith, has branches that are so long that this single tree covers a full square block in the city.
Much about aerial roots is still unknown.
There are two main kinds of roots systems: "taproot systems" and "fibrous root systems". A taproot system has one thick main root growing down from the plant's stem, and lots of smaller "secondary roots" branching off from this. A taproot system is usually deeper than it is wide. Often, we eat taproots, like carrots and turnips.
A "fibrous root system" has lots of roots growing in many directions. There is not one main root. A fibrous root system is usually wider than deep.
It has been usually assumed that in regular (non-aerial) terrestrial roots, the nutrients are pumped in together with the water, and that water is pumped into the roots by osmosis. Recent studies in large trees such as the Giant Sequoia, showed, that much of the pumping power, after initial growth, is received by hydraulic suction, due to transpiration - water evaporation from the leaves, in addition to the strong capillary action in the plant's branching xylem in the stem and leaves.
Demo
Demo may mean one of the following:
Piero Gobetti
Piero Gobetti (born 1901 – died February 1926) was a young journalist, intellectual, and radical liberal person. He was a very active critic during the years of crisis in Italy after the First World War and during the early years of Fascist rule. He had to leave Italy and settled down in Paris, where he soon died. He died because his health was bad, after the Fascists had terrorized him.
Manama
Manama is the capital city of Bahrain. It is also the largest city in Bahrain, having almost 150.000 residents.
Manama has been a city since at least the 1300s, when it was mentioned in Islamic books. It was owned by Portugal from 1521 to 1602, by Persia from 1602 to 1783, and by the Al-Khalifa family for a long time after that. In 1971, Manama became the capital city of Bahrain.
The city is divided into a few parts:
Protist
Protists are single-celled eukaryotes (which are organisms with a nucleus). The term Protista was first used by Ernst Haeckel in 1866. The protists are not a natural group, or clade, since they have no common origin. Like algae or invertebrates, they are often grouped together for convenience.