Obi worn for practicing martial arts are a lot thinner and shorter than other kinds of obi. They come in different colours, and the colours show how skilled someone is in practicing martial arts. When someone becomes skilled enough, they wear a new colour of obi. Both men and women wear the same size and length of obi in martial arts, and they are not decorated with embroidery or dyes designs.
Nitrogen fixation
Nitrogen fixation is the process by which nitrogen in the air (N) is changed (converted) into ammonia () or other nitrogenous compounds in the soil.
Nitrogen fixation is essential to life because nitrogen compounds are needed for making all nitrogen-containing organic compounds, such as amino acids, proteins, and nucleic acids.
Atmospheric nitrogen is a relatively unreactive molecule. It is useless to all except a few bacteria and archaea. Biological nitrogen fixation converts into ammonia, which is used (metabolized) by most organisms.
Nitrogen is fixed in biological and non-biological ways:
Cyanobacteria are in most environments on Earth. They play key roles in the carbon and nitrogen cycle of the biosphere. Cyanobacteria use many sources of combined nitrogen, like nitrate, nitrite, ammonium, urea, or some amino acids.
Several cyanobacteria are also diazotrophs which can fix nitrogen from the air. This is an ability which may have been present in their last common ancestor in the Archaean.
Cyanobacteria in coral reefs can fix twice the amount of nitrogen than on land—around 1.8 kg of nitrogen is fixed per hectare per day. The colonial marine cyanobacterium "Trichodesmium" may fix nitrogen on such a scale that it accounts for almost half of the nitrogen-fixation in marine systems on a global scale.
Plants that contribute to nitrogen fixation include the legume family – Fabaceae – with taxa such as kudzu, clovers, soybeans, alfalfa, lupines, peanuts, and rooibos. They have symbiotic bacteria called "Rhizobia" in nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed
nitrogen is released, making it available to other plants and this helps to fertilize the soil. Most legumes have this association, but a few genera (e.g., "Styphnolobium") do not. In traditional farming practice, fields are rotated through various types of crops, which usually includes one consisting mainly or entirely of clover or buckwheat (non-legume family "Polygonaceae"), which are often referred to as "green manure".
Although most plants able to form nitrogen-fixing root nodules are in the legume family Fabaceae, there are a few exceptions:
All these families belong to the orders Cucurbitales, Fagales, and Rosales, which together with the Fabales form a clade. In this clade, Fabales were the first lineage to branch off; thus, the ability to fix nitrogen was lost in most descendants of the original nitrogen-fixing plant.
Biological nitrogen fixation was discovered by Hermann Hellnegel (18311895) and Martinus Beijerinck (18511931).
Britské listy
Britské listy is an Internet cultural and political daily published in the Czech Republic. It specialises in critical analysis of Czech politics; some Czech commentators consider this as "left-wing views". It is editorially open and will publish stimulating pieces by authors from any part of the political spectrum
Nitrogen cycle
The nitrogen cycle is the way that nitrogen in nature is changed into many different forms that are used by living organism[s].
Air is about 78% nitrogen. Nitrogen chemicals are needed for life. Nitrogen is a necessary part of proteins, DNA, and RNA. In plants, nitrogen is needed for photosynthesis and growth. However, living things cannot use the elemental nitrogen in the air for these things. Nitrogen fixation is needed to change the nitrogen in air (N) into forms that can be used by life. Most nitrogen fixation is done by microorganisms called bacteria. These bacteria have an enzyme that combines N with hydrogen gas (H) to make ammonia (NH).
Some of these bacteria live in the roots of plants (mostly legumes). In these roots, they make ammonia for the plant and the plant gives them carbohydrates. Other plants take nitrogen compounds out of the soil through their roots. All nitrogen in animals comes from eating plants.
Ammonium (NH) in soil is made by nitrogen-fixing bacteria and decomposers, bacteria and fungi that break down dead life into its parts. This process is called "ammonification". Ammonium has a positive charge. It easily joins to clay and humus in the soil. Ammonia and ammonium are poisonous to fish and other animals. Sewage and other waste-water is regularly measured because of this. If ammonia levels are too high, "nitrification" must happen.
Nitrification is the oxidation of ammonia and ammonium to nitrite (NO) and then to nitrate ( NO) by bacteria. Because nitrite and nitrate have a negative charge they do not easily join to soil and will wash out of the soil during rain and irrigation. High nitrate levels in drinking water is harmful for babies and can cause blue-baby syndrome. High nitrate levels can also cause too much algae growth in lakes and pools. This eutrophication can be harmful to fish and other water animals. The use of fertilizers is controlled because of this.
Where there is no oxygen, some bacteria will make nitrate into nitrogen gas (N) to extract energy. This starts the nitrogen cycle over again. This process is called "denitrification".
Moscow State University
Lomonosov Moscow State University (MSU; ) is the largest and oldest university in Russia. It was made in 1755 and is in Moscow. It was made by Ivan Shuvalov and Mikhail Lomonosov. It is named after Lomonosov.
The university building which can be seen in the picture, is an example of Stalinist architecture. In total, there are seven such towers around Moscow. The tower at the university is the largest one. The tower was designed by architect Lev Vladimirovich Rudnev. It was built after the war. He was awarded the Stalin Prize for its construction, in 1949. The building was the largest skyscraper outside New York for a long time. It was the tallest buildimg in Europe, until 1988. The central tower is 240m high. It has 36-stories. It is flanked by four huge wings of student and faculty accommodations. It is said to contain a total of 33 kilometers of corridors and 5,000 rooms. Facilities that are inside the building include a concert hall, a theatre, a museum, various administration services, a library, a swimming pool, a police station, a post office, a laundry, a hairdresser's salon, a canteen, bank offices, shops, cafeterias, and a bomb shelter. Along with the university administration, four of the main faculties - Faculty of Mechanics and Mathematics, the Faculty of Geology, the Faculty of Geography, and the Faculty of Fine and Performing Arts - now are in the Main building. The star on the top of the tower is large enough so that it has a small room and a viewing platform; it weighs 12 tons. The building's facades are decorated with giant clocks, barometers, and thermometers, statues, carved wheat sheaves, and Soviet crests (recently renovated). It stands before a terrace featuring statues of male and female students gazing optimistically and confidently into the future.
Boarding school
A boarding school is a school where students live and sleep. Some boarding schools have day students who go home at the end of the school day. If the school costs money, they don't have to pay as much money. A person who stays at a boarding school is called a "boarder". In the UK 1% of children go to boarding schools and 13% of private school pupils are boarders. Most boarding schools are private. This means that as well as having to pay to sleep there, students have to pay for their education.
In Ghana most secondary schools are boarding.