the-french-artist/wikipedia_20220301.simple_sentence_split huggingface dataset:
Large amounts of the vitamin are used in orthomolecular medicine and no harmful effects have been observed even in doses of 10,000 mg per day or more.
Therapeutic uses
Vitamin C is needed in the diet to prevent scurvy.
It also has a reputation for being useful in the treatment of colds and flu.
The evidence to support this idea, however, is ambiguous and the effect may depend on the dose size and dosing regime.
The Vitamin C Foundation recommends 8 grams of vitamin C every half hour to show an effect on cold symptoms.
Vitamin C advocacy
One meta-study of the published research examined the effectiveness of ascorbic acid in the treatment of infectious disease and toxins.
It was conducted in 2002 by Dr. Thomas Levy, Medical Director of the Colorado Integrative Medical Center in Denver.
It claimed that overwhelming scientific evidence exists for its therapeutic role.
Some vitamin C advocates say that vitamin C is not used therapeutically because it cannot be patented.
Pharmaceutical companies seek to generate revenue and profit their shareholders.
They may be reluctant to research or promote something that will make them little money.
DCPIP (its full name is 2,6-dichlorophenolindophenol) is a blue chemical used as a dye because when it is oxidized it is blue.
Once DCPIP is reduced (by addition of electrons) it does not have a color anymore.
This reaction can be reversed, and the colourless DCPIP will turn blue again, when it is oxidized.
DCPIP is often used to measure the electron transport chain in plants.
It has a higher redox potential (electron affinity) than the Fe-S complex in cytochrome b and will therefore "steal" electrons from it.
This means that cytochrome c does not  receive them.
The process cuts off the electron supply of  photosystem I. A common way to illustrate this change is by the addition of vitamin C solution.
This reduces the 'jelly' by transforming it to a colourless mass.
This experiment can be carried out to illustrate the effect of changing cell sizes on SA/V (surface area:volume ratio).
This is known as Titration.
Mathews, Ahern, Van Holde, Biochemistry, Addison Wesley Longman Inc., 2000 pp534–5
A healthy diet or balanced diet is a diet (what you eat) that contains the right amounts of all the food groups.
It includes fruit, vegetables, grains, dairy products, and protein.
It does not include too much or too little of any kind of food.
Eating wrong amounts of a food group, whether it be too much or too little, is called an "unhealthy diet" or an "imbalanced diet".
A healthy diet is one that includes more foods that come from plants and fewer convenience foods.
Basic nutrition
What is known about nutrition and diet keeps changing as more is learned.
However, basic nutrition remains much the same.
The best advice is to talk to a doctor or dietitian for personalized information based on an individual's lifestyle, health, and food likes and dislikes.
Basic nutrition begins with a diet based on the major food groups that includes vegetables, whole grains, and dairy products.
It should also have lean protein such as beans, legumes, nuts and seeds plus healthy fats.
A basic nutrition plan should include guidelines for how much food from each group to eat.
Foods should be those that can be found in local grocery stores instead of specialty and gourmet food stores.
A basic food plan should be based on an individual's budget, lifestyle and (healthy) preferences.
Drink fewer Soft drinks, energy drinks and sports drinks which usually have sugar.
Read the food labels to see what is in the foods.
For example, labels usually show what foods are lower in sodium such as in soup, bread, and frozen meals.
A healthy diet should include seafoods (such as salmon, tuna, and trout) and shellfish (such as crab, mussels, and oysters).
Seafood has protein, minerals, and omega-3 fatty acids which are heart-healthy.
Basic nutrition should contain balanced amounts of macronutrients for energy.
Carbohydrates are one of the three macro-nutrients in the human diet (fat and protein are the other two).
A healthy diet can replace dieting for weight loss.
Eating healthy, along with physical exercise and practicing moderation, can lead to better health in the long run.
Special diets
There are some diets made for people with some diseases.
DASH diet (Dietary Approaches to Stop Hypertension)
Gluten-free diet (Coeliac disease)
Ketogenic diet (Epilepsy)
Dye is a substance used to color materials.
It is often used to color the fabric used to make clothing.
It has low solubility.
A pigment won't do this because it won't stick to the fibers of the fabric and color them.
A dye can be natural, usually made from plant material such as berries, or artificial, meaning that it is made by humans from chemicals such as petrochemicals.
Most natural dyes are gotten from different parts of a plant like the roots, fruits, bark, leaves, wood, fungi and lichens.
Most dyes are synthetic and are made from petrochemicals.
Acid dyes can dissolve in water.
They are used on fibers such as silk, wool, nylon.
Most food coloring that are made by man are acid dyes.
Examples of acid dye are Alizarine Pure Blue B, Acid red 88, etc.
Basic dyes can dissolve in water.
They are mainly used on acrylic fibers.
They may also be used on wool and silk.
Basic dyes are also used to make paper colourful.
Food coloring#Natural food dyes
Poetry can be as short as a few words, or as long as a book.
A poem as short as one line is called a monostich.
A poem that is as long as a book is an epic.
There are many "poetic forms" (forms of poetry).
Some of forms are: Sonnet, Haiku, Ballad, Stev, Prose poem, Ode, Free verse, Blank verse, thematic, limerick and nursery rhymes.
Poetry can be used to describe (comparing, talking about, or expressing emotion) many things.
It can make sense or be nonsense, it can rhyme or not.
It can have many shapes and sizes; it can be serious or funny.
Digital Poetry
A more modern approach is digital poetry.
Computers and webtechnology is used to express poetry and make it interactive.
So called interdisciplinary poetry (wich means combination of different forms of poetry) are made possible by linking the poetic texts with audio, video or web-animation (e.g. with CSS) or among themselves via hyperlinks.
Modern artists use digital poetry to not only express artistic intention, but also to design a layout around their texts.
An example for this use of interdisciplinary art, which combines abstract text and abstract visuals is the german project "Schwarzer Flamingo".
It uses digital poetry to collect pieces of written art but also to give different artists a plattform.
So some projects of digital art can be described as a form of an artwork as well as an exhibition.
Literature is a group of works of art made up of words.
Most are written, but some are passed on by word of mouth.
Literature usually means a work of poetry, theatre or narrative.
There are many different kinds of literature, such as poetry, plays, or novels.
They can also be put into groups through their language, historical period, origin, genre, and subject.
The word "Literature" comes from the Latin word "Literatura" (English: "Learning", "Writing", "Grammar").
Most of the earliest works were epic poems.
Epic poems are long stories or myths about adventures.
Ramayana and Mahabharta, two Indian epics, are still read today.
Odyssey and Iliad are two famous Greek poems by Homer.
They were passed down through speaking and written down around the 8th century BC.
Imagination is the ability to form images of things or events in one's mind.
When someone imagines something, they are trying to picture something in their mind that they are not experiencing at the moment or that is not really happening.
A calorimeter is a tool that measures the amount of thermal energy contained in a substance, or released in a reaction.
A commonplace use is to measure heat of combustion.
In biology, a bolus (from the Latin word for ball), is a ball-shaped living thing.
In medicine, a bolus is a large amount of a drug given to patients to raise the blood level before treatment.
A bolus can also refer to a ball of food after it has been chewed.
It passes down the oesophagus by peristalsis.
The oesophagus (or esophagus) is also called the gullet.
It is the part of the gastrointestinal system between the mouth and the stomach.
It connects the pharynx and the stomach.
It is about  long.
The oesophagus is lined with muscle, and is lubricated.
Its muscle pushes food down into the stomach.
The oesophagus can contract or expand to allow for the passage of food.
The muscular movement that pushes the food down the oesophagus is called peristalsis.
At the entrance to the stomach there is a ring of muscle called a sphincter.
This is usually closed, but relaxes as food approaches, allowing it to enter the stomach.
In the stomach, the food is churned until it turns into a soupy mixture called chyme.
Anatomy of the digestive system
A protease is a digestive  enzyme.
It breaks down long chains of  proteins into shorter amino acids.
Proteases have evolved a number of times.
We know this because different kinds of protease can do the same reaction in completely different ways.
Proteases are found in animals, plants, bacteria, archaea and viruses.
Now more than 50 types of protease are known.
Each is a separate evolutionary origin of proteolysis.
serine proteases
threonine proteases
cysteine proteases
aspartate proteases
metallo proteases
glutamic acid proteases
Dental floss is a special type of thread.
It is used for cleaning spaces between teeth which cannot be reached by toothbrushes.
It is important to floss before brushing teeth and to floss at least once a day.
Tooth brushing will not clean food that is packed between teeth.
This 'food packing' can lead to unhealthy teeth and gums.
Bacteria grow in this 'packed food' between teeth.
These bacteria cause the surface of teeth (enamel) to break down.
Then the teeth and gums and sometimes even the jaw can become seriously diseased.
These bacteria that come from the food on the teeth and between the teeth are called "plaque" or "bacterial plaque" and also can cause the gums to become less healthy. "
Gingivitis" which means gum disease is one type of disease that flossing helps to prevent.
Very serious diseases can start on the teeth and move to the bone of the jaw, damaging the jaw badly.
Flossing your teeth reduces the danger of these serious diseases of the jaw bone.
These hard-to-cure jaw bone diseases are called "periodontal disease".
Food that is trapped between the teeth can be uncomfortable and even cause pain.
Some food is hard, for example meat, apple.
Ground meat is soft and so is apple sauce.
Chicken and turkey meat are hard and full of fibres and very often get trapped between the teeth.
When hard food is trapped between the teeth it can cause discomfort and sometimes pain.
When hard food is pressed by the teeth against the gum it can cause pain.
Some people use toothpicks to try to remove trapped food from between the teeth and other people use dental floss to do this.
Dental floss can do most things that a toothpick can do but dental floss is much thinner than a toothpick and can thus get to places that most toothpicks cannot reach.
So floss presumably does a better job at getting bits of food out from between the teeth, relieving discomfort and pain quicker.
When a person first starts flossing, bleeding can happen.
This is normal and happens because teeth and gums that are not flossed are less healthy.
It will stop as the teeth and gums get healthier with flossing.
Rickets is a disease that happens in young children.
It happens in children who do not get enough vitamin D and calcium.
It causes larger spaces inside bones, and makes them dry, like sponges.
It can make the legs curve toward each other (so the knees touch) or away from each other.
The word "rickets" comes from the Greek word rhakhis, which means "spine."
Vitamin D helps the bones absorb (take up) calcium.
Low vitamin D makes it hard to absorb calcium.
The human body makes vitamin D3 in the skin, from cholesterol.
Then the liver changes vitamin D3 into calcitriol, which sends calcium from the blood into the bones.
The bones need calcium to stay strong.
However, the skin will not make vitamin D3 unless enough ultraviolet light shines on it.
Sunlight contains ultraviolet light, so getting enough sun is one way of getting enough D3.
People need calcium for calcification.
Calcification uses calcium to help make bones bigger and stronger.
Low calcium makes bones delicate and easier to break.
The best way to do this is to get a lot of sunlight, and eat foods that have a lot of vitamin D and calcium in them.
However, people who cannot get enough vitamin D and calcium this way can take supplements (vitamin pills that have calcium and vitamin D in them).
Milk and other dairy products like cheeses
Some green vegetables, like broccoli, spinach, and kale
Today, many products are "fortified" with vitamin D: the vitamin was added when the food was made.
These foods include some kinds of orange juice, breakfast cereals, breads, and even bottled water.
The food's label will say how much calcium it has in it.
Calcium is absorbed best by the bones when it is taken in amounts of 1000mg or less.
Because of this, doctors suggest eating smaller amounts of foods with calcium in them, at different times in the day, instead of all at once.
There are three ways to get vitamin D: sunlight, foods, or supplements (vitamin pills that have vitamin D in them).
However, many people cannot get enough vitamin D just from their diet.
There are only a few foods that have a lot of vitamin D in them.
"Fatty fish" that were caught in the wild, like mackerel, salmon, and tuna
Cooked egg yolk
Vitamin D is added to some foods, like some kinds of dairy products, cereals, and orange juices
Breast milk may not have enough vitamin D in it to prevent rickets.
Babies who are only breastfed, and not fed any other foods, may be given vitamin D drops to make sure they do not get rickets.
However, this is not a significant risk if mothers and child have some exposure to sunlight.
Children with dark skin are more likely to need additional vitamin D.
They are between three and 36 months old.
Children this age are at the greatest risk for rickets because their bones are growing so quickly, and are supposed to get bigger and stronger during this time
They were born prematurely (earlier than normal)
They live in the Northern parts of the world, where there is less sunshine
They spend too little time outside
They always wear sunscreen when going out
Even mild sunscreen decreases the amount of vitamin D the body makes by 95% (by stopping the body from taking in vitamin D from sunlight)
However, people should still wear sunscreen when they might get sunburned
They do not eat enough food that has calcium or vitamin D in it, because of lactose intolerance or a strict vegan diet
They cannot make or use vitamin D because of a medical disorder, like coeliac disease, or because they take certain anti-seizure medications
Brittle (easily broken) bones or teeth
Bleeding more than normal
Stunted growth (not growing like a healthy child would)
Weakness (feeling tired all the time)
Body pain
Diseases and disorders of bones
Bile or gall is a green-yellow fluid.
It is secreted from the liver of most vertebrate animals, and is often stored in the gall bladder.
Bile helps digest fat.
Bile pigments
Bile salts
The name gall comes from the Greek word cholè meaning green or yellow.
Bile is also stored in bile ducts.
Often after liver transplants, bile comes out of the body.
The dental pulp is the part in the center of a tooth (pulp cavity).
It is made up of living soft tissue and cells.
It is surrounded by dentine and contains nerves and blood and lymph vessels.
Protoplasm is an old term, which  means the living substance that makes up a cell.
It is no longer much used.
Biologists prefer to talk about the cytoplasm and the cell nucleus.
In plant cells, it is surrounded by a cell wall.
In animal cells, the whole cell is made of protoplasm, surrounded by a cell membrane.
Protoplasm in living beings is made up of about 7580% water.
However, this is rather misleading because the cytoplasm is full of structures called organelles, which do various tasks.
The endoplasmic reticulum is the largest of these structures; there are many other organelles.
The word "protoplasm" was first used in 1846 by Hugo von Mohl to describe the substance in plant cells, apart from the cell wall, the cell nucleus and the vacuole.
After the invention of the electron microscope it was clear that a living cell is much more complicated than von Mohl knew.
More accurately, it is a family of similar enzymes which work in a wide range of animals, plants and fungi.
There are two variants in humans: alpha-amylase, and gamma-amylase.
Alpha-amylase is a major digestive enzyme.
Its optimum pH is 6.7–7.0.
It is found in saliva and pancreatic juice.
It takes starch chains and breaks them into smaller pieces with two or three glucose units.
It can break down starch into maltose.
It works in the mouth and stomach during digestion.
The gamma-amylase has most acidic optimum pH of all amylases because it is most active around pH 3.
Therefore, it works best in the stomach, which does have an acidic pH.
Apparently, early humans did not possess salivary amylase.
The closest evolutionary relatives of humans, chimpanzees and bonobos, have either one or no copies of the gene for producing salivary amylase.
A duplication event of the AMY1 gene led to the production of amylase in the saliva.
The same event occurred independently in rodents.
This shows the importance of salivary amylase in organisms that eat relatively large amounts of starch.
After the agricultural revolution, human diet began to rely more on plant and animal domestication in place of hunting and gathering.
This shift marked the beginning of a diet composed of 49% carbohydrates as opposed to the previous 35% observed in Paleolithic humans.
As such, starch became a staple of human diet.
Humans that contained amylase in the saliva would benefit from increased ability to digest starch more efficiently and in higher quantities.
Not all humans have the same number of copies of the AMY1 gene.
Populations which rely on carbohydrates have a higher number of AMY1 copies than populations that eat little starch.
The number of AMY1 gene copies in humans can range from six copies in agricultural groups such as European-American and Japanese (two high starch populations) to only 2-3 copies in hunter-gatherer societies such as the Biaka, Datog, and Yakuts.
The correlation between starch consumption and number of AMY1 copies suggests that more AMY1 copies in high starch populations is caused by natural selection.
It is a favorable phenotype for those individuals.
Therefore, it is likely that having more copies of AMY1 in a high starch population increases fitness and produces healthier, fitter offspring.
Geographically close populations with different eating habits possess a different number of copies of the AMY1 gene.
This offers strong evidence that natural selection has acted on this gene.
A variegated leaf is useful in conducting experiments to show that chlorophyll is needed for photosynthesis to happen.
They are also popular in horticulture.
Place the leaves in boiling water for six minutes to soften the cells, and then in ethanol (alcohol).
When the leaves are drained of colour, spread them out on a flat surface.
Soak the leaves in iodine and the green parts will turn blue/black and the non green parts will stay the yellowish brown colour of iodine liquid.
The green parts contain starch, which makes iodine turn blue/black.
The blue/black stain is what shows starch is present.
You could take "before & after" photos to prove the black areas were green at the start.
A seam ripper is a cutting tool.
It is used for removing stitches in sewing and cutting open buttonholes made on a sewing machine.
Sometimes it is also called a thread ripper.
The tool usually has a handle, shaft, and head.
The head has two points: one flattened to form a pointed blade and the other  forming a small point.
To use a seam ripper to remove sewn threads, the blade is placed underneath the thread to be cut.
The thread slips down between the two points, and the tool is then lifted upwards allowing the blade to cut through the thread.
Then the loose thread ends can be removed.
a plaque in biology is a flat growth-form, as for example,
the growth of bacterial colonies on an agar plate
a sticky, white film or fluid on the teeth, a mixture of bacteria and food
in atherosclerosis, a fat layer inside an artery.
a flat man-made object, such as a memorial plaque or other flat object
A pin cushion is small cushion used for holding pins and needles.
It is used so that the pins and needles are stored safely and can be taken out by pulling the head.
A chemical cell converts chemical energy into electrical energy.
Most batteries are chemical cells.
A chemical reaction takes place inside the battery and causes electric current to flow.
There are two main types of batteries - those that are rechargeable and those that are not.
A battery that is not rechargeable will give electricity until the chemicals in it are used up.
Then it is no longer useful.
It can be rightly called 'use and throw'.
A rechargeable battery can be recharged by passing electric current backwards through the battery; it can then be used again to produce more electricity.
It was Gaston Plante, a French scientist who invented these rechargeable batteries in 1859.
Batteries come in many shapes and sizes, from very small ones used in toys and cameras, to those used in cars or even larger ones.
Submarines require very large batteries.
Types of chemical cells
Simple cell
Electric cell
Electrochemical cells
An extremely important class of oxidation and reduction reactions are used to provide useful electrical energy in batteries.
A simple electrochemical cell can be made from copper and zinc metals with solutions of their sulphates.
In the process of the reaction, electrons can be transferred from the zinc to the copper through an electrically conducting path as a useful electric current.
An electrochemical cell can be created by placing metallic electrodes into an electrolyte where a chemical reaction either uses or generates an electric current.
Electrochemical cells which generate an electric current are called voltaic cells or galvanic cells, and common batteries consist of one or more such cells.
In other electrochemical cells an externally supplied electric current is used to drive a chemical reaction which would not occur spontaneously.
Such cells are called electrolytic cells.
Voltaic cells
An electrochemical cell which causes external electric current flow can be created using any two different metals since metals differ in their tendency to lose electrons.
Zinc more readily loses electrons than copper, so placing zinc and copper metal in solutions of their salts can cause electrons to flow through an external wire which leads from the zinc to the copper.
As a zinc atom provides the electrons, it becomes a positive ion and goes into aqueous solution, decreasing the mass of the zinc electrode.
On the copper side, the two electrons received allow it to convert a copper ion from solution into an uncharged copper atom which deposits on the copper electrode, increasing its mass.
The two reactions are typically writtenZn(s) --> Zn2+(aq) + 2e-Cu2+(aq) + 2e- --> Cu(s)The letters in parentheses are just reminders that the zinc goes from a solid (s) into a water solution (aq) and vice versa for the copper.
It is typical in the language of electrochemistry to refer to these two processes as "half-reactions" which occur at the two electrodes.
In order for the voltaic cell to continue to produce an external electric current, there must be a movement of the sulfate ions in solution from the right to the left to balance the electron flow in the external circuit.
The metal ions themselves must be prevented from moving between the electrodes, so some kind of porous membrane or other mechanism must provide for the selective movement of the negative ions in the electrolyte from the right to the left.
Energy is required to force the electrons to move from the zinc to the copper electrode, and the amount of energy per unit charge available from the voltaic cell is called the electromotive force (emf) of the cell.
Energy per unit charge is expressed in volts (1 volt = 1 joule/coulomb).
Clearly, to get energy from the cell, you must get more energy released from the oxidation of the zinc than it takes to reduce the copper.
The cell can yield a finite amount of energy from this process, the process being limited by the amount of material available either in the electrolyte or in the metal electrodes.
For example, if there were one mole of the sulfate ions SO42- on the copper side, then the process is limited to transferring two moles of electrons through the external circuit.
The amount of electric charge contained in a mole of electrons is called the Faraday constant, and is equal to Avogadro's number times the electron charge:Faraday constant = F = NAe = 6.022 x 1023 x 1.602 x 10-19 = 96,485 Coulombs/moleThe energy yield from a voltaic cell is given by the cell voltage times the number of moles of electrons transferred times the Faraday constant.
Electrical energy output = nFEcellThe cell emf Ecell may be predicted from the standard electrode potentials for the two metals.
For the zinc/copper cell under the standard conditions, the calculated cell potential is 1.1 volts.
A simple cell typically has plates of copper (Cu) and zinc (Zn) in dilute sulphuric acid.
The zinc dissolves and bubbles of hydrogen appear on the copper plate.
These hydrogen bubbles interfere with the passage of current so a simple cell can only be used for a short time.
To provide a steady current, a depolarizer (an oxidizing agent) is needed to oxidize the hydrogen.
In the Daniel cell, the depolarizer is copper sulphate, which exchanges the hydrogen for copper.
In the Leclanche battery, the depolarizer is manganese dioxide, which oxidizes the hydrogen to water.
Daniel cell
Zinc rod = negative terminal
H2SO4 = dilute sulphuric acid electrolyte
Porous pot separates the two liquids
CuSO4 = copper sulphate depolarizer
Copper pot = positive terminal
Das Lied der Deutschen ("The Song of the German people"), also known as Deutschlandlied, ("The Song of Germany"), is a song written by Joseph Haydn and Hoffmann von Fallersleben.
Part of this song is the national anthem of Germany (German National Anthem).
A line from this song, "Einigkeit und Recht und Freiheit" ("Unity and justice and freedom") is the considered to be the unofficial motto of Germany.
The music was written by Haydn in 1797 as the anthem of Austria.
It was called "Gott erhalte Franz den Kaiser" ("God protect our Emperor Franz").
The words which are used today were written by the poet August Heinrich Hoffman von Fallersleben in 1841.
Today, the first line "Germany, Germany above all" sounds too strong for some people, and is often misunderstood.
Fallersleben wanted a united Germany when he wrote it.
At that time, Germany was not one country, but many small countries.
So "Germany above all" meant that the most important thing to do was to have a unified Germany.
Also, the poet was in Heligoland, where people spoke German but were ruled by the British.
Fallersleben's music was very popular in Germany during the second part of the 19th century.
This song was not a national anthem then, but a patriotic song supporting a united German state.
In 1918, it replaced the anthem of the German Empire "Heil Dir im Siegerkranz" ("Praise to the war-winner"), when the Emperor Wilhelm II lost power at the end of the First World War.
In 1921, a "fourth stanza", a new part or verse, was written by poet Albert Matthai with words about the difficult life in Germany at that time.
This verse was rarely used.
During the time of Hitler, only the first part of the song was used.
This was often followed by a Nazi party song.
This offended the international audience as the first stanza supports Germany holding colonial powers in non-consenting nations.
After the Second World War, Germany was divided into two countries.
In 1949, the new Western Germany tried to get a new song for the national anthem.
Another song was chosen, written by poet Rudolf Alexander Schröder.
It was not very popular.
Finally, the third part of the Fallersleben song was made into the national anthem.
In the other part of Germany, the Eastern Germany, the words of poet Johannes R. Becher ("Auferstanden aus Ruinen" - "Re-built from the Ruins") were used with a song written by Hanns Eisler.
It was not very popular, and from the 1970s the words were not sung, because of the line "Germany, [our] unified fatherland".
After East and West Germany united again in 1990, the Fallersleben song again became the national anthem of Germany but only the third part is used.
Today, the first part of the song is popular with nationalist extremists.
German National Anthem
Dental cavity, damage to teeth.
Another hollow area within the body.
Such as a nasal cavity.
Evidence is something that is used to support an argument.
It gives examples of why something is true.
For example, if someone come across a cup of spilled milk, that person could look for evidence as to how the milk was spilled.
If hairs of a cat and paw prints were found on the ground, they could be evidence that a cat was the cause of the spilled milk.
If a witness saw the cat spilling the milk, her testimony would also be evidence.
A dyadic is a math function that needs two things in order to give something out.
Addition and multiplication are dyadic.
Powers are also dyadic.
There are many more functions that are dyadic.
Dyadic communication
Dyadic counterpoint, the voice-against-voice conception of polyphony
Dyadic fraction
Dyadic product
Dyadic rational (also known as Dyadic solenoid)
Dyadic Relation (usually known as a Binary relation)
Dyadic tensor
Dyadic transformation
A hill is a landform that is higher than the surrounding terrain and that is smaller than a mountain.
Hill is a  highland  of much lower elevation than a mountain.
Normally it is not as steep as a mountain.
By definition, a hill is often described as being lower than 600 meters (about 2,000 feet).
However, some definitions say a hill is lower than 300 meters (about 1,000 feet).
The surface of a hill is much more stable than that of a dune.
Hill have long been used for hill forts
nds:Kommun Ås
An enzyme is a protein molecule in cells which works as a biological catalyst.
Enzymes speed up chemical reactions in the body, but do not get used up in the process, therefore can be used over and over again.
Almost all biochemical reactions in living things need enzymes.
With an enzyme, chemical reactions go much faster than they would without the enzyme.p39  Other biocatalysts are catalytic RNA molecules, called ribozymes.
The substances at the start of a reaction are called substrates.
The substances at the end of a reaction are the products.
Enzymes work on the substrates, and turn them into products.
The study of enzymes is called enzymology.
Enzyme structure
There are thousands of different enzymes and each one is specific to the reaction which it catalyses.
Enzymes have names which show what they do.
Enzyme names usually end in –ase to show that they are enzymes.
Examples of this include ATP synthase.
It makes a chemical called ATP.
Another example is DNA polymerase.
It reads an intact DNA strand and uses it as a template to make a new strand.
One example of an enzyme is amylase, found in saliva.
It breaks down starch molecules into smaller glucose and maltose molecules.
Another kind of enzyme is lipase.
It breaks down fats into smaller molecules, fatty acids and glycerol.
The proteases are a whole class of enzymes.
They break down other enzymes and proteins back into amino acids.
Nucleases are enzymes that cut DNA or RNA, often in specific place in the molecule.
Enzymes are not only for breaking large chemicals into smaller chemicals.
Other enzymes take smaller chemicals and build them up into bigger chemicals, and do many other chemical tasks.
The classification below lists the main types.
Biochemists often draw a picture of an enzyme to use as a visual aid or map of the enzyme.
This is hard to do because there may be hundreds or thousands of atoms in an enzyme.
Biochemists can not draw all this detail.
Instead, they use ribbon models as pictures of enzymes.
Ribbon models can show the shape of an enzyme without having to draw every atom.
Most enzymes will not work unless the temperature and pH are just right.
In mammals the right temperature is usually about 37oC degrees (body temperature).
The correct pH can vary greatly.
Pepsin is an example of an enzyme that works best when pH is about 1.5.
Heating an enzyme above a certain temperature will destroy the enzyme permanently.
It will be broken down by protease and the chemicals will be used again.
Some chemicals can help an enzyme do its job even better.
These are called activators.
Sometimes, a chemical can slow down an enzyme or even make the enzyme not work at all.
These are called inhibitors.
Most drugs are chemicals that either speed up or slow down some enzyme in the human body.
Lock and key model
Enzymes are very specific.
In 1894 Emil Fischer suggested that both the enzyme and the substrate have specific complementary geometric shapes that fit exactly into one another.
This is often referred to as "the lock and key" model.
However, this model fails to explain what happens next.
In 1958, Daniel Koshland suggested a modification to the lock and key model.
Since enzymes are rather flexible structures, the active site is reshaped by interactions with the substrate.
As a result, the substrate does not simply bind to a rigid active site.
The amino acid side-chains of the active site are bent into positions so the enzyme does its catalytic work.
In some cases, such as glycosidases, the substrate molecule also changes shape slightly as it enters the active site.
Substrate + Enzyme –> Substrate:Enzyme –> Product:Enzyme –> Product + Enzyme
Enzymes lower the activation energy of a reaction by forming an intermediary complex with the substrate.
This complex is called an enzyme-substrate complex.
For example, sucrase, 400 times the size of its substrate sucrose, splits the sucrose into its constituent sugars, which are glucose and fructose.
The sucrase bends the sucrose, and strains the bond between the glucose and fructose.
Water molecules join in and make the cleavage in a fraction of a second.
Enzymes have these key features:
They are catalytic.
They commonly increase the rate of reaction 10 billion-fold.p39 The enzyme itself is not changed by the reaction.
They are effective in tiny amounts.
One enzyme molecule may convert 1000 molecules of substrate a minute, and some are known to convert 3 million in a minute.p39
They are highly specific.
One enzyme will only carry out one of the many reactions of which a substrate is capable.
Control of enzyme activity
Enzyme production (transcription and translation of enzyme genes) can be increased or reduced in response to changes in the cell's environment.
This form of gene regulation is called enzyme induction and inhibition.
For example, in bacteria which are resistant to antibiotics such as penicillin, enzymes are induced which hydrolyse the penicillin molecule.
Enzymes can occur in different cellular compartments.
For example, fatty acids are synthesized by one set of enzymes in the cytosol, endoplasmic reticulum and Golgi apparatus.
Then they are used by a different set of enzymes as a source of energy in the mitochondria.
Enzymes can be regulated by their own products.
For example, the end product(s) often inhibit one of the first enzymes of the pathway.
Such a regulatory mechanism is called negative feedback, because the amount of the end product produced is regulated by its own concentration.
This prevents the cells making too much enzyme.
The control of enzyme action helps keep a stable internal environment in living organisms.
Enzymes can be regulated by being modified after their production.
An example is the cleavage of the polypeptide chain.
Chymotrypsin, a digestive protease, is produced in inactive form in the pancreas and transported in this form to the stomach where it is activated.
This stops the enzyme from digesting the pancreas or other tissues before it enters the gut.
This type of inactive precursor to an enzyme is known as a zymogen.
Some enzymes may become activated when they move to a different environment (e.g. from high pH to low pH).
For example, haemagglutinin in the influenza virus is activated by a change in shape.
This is caused by the acidic conditions which occur inside the host cell's lysosome.
Inhibitors can be used to stop an enzyme from binding to a substrate.
This may be done to slow down an enzyme-controlled reaction.
The inhibitors fit loosely or partially into the enzyme's active site.
This prevents or slows down an enzyme-substrate complex being formed.
Denaturation
Denaturation is the irreversible alteration of an enzyme's active site, caused by an extreme change in temperature or pH. It will decrease the rate of reaction because the substrate molecule will not be able to fit into the active site, so products cannot be formed.
Cofactors, or coenzymes, are helper molecules which are needed to make an enzyme work.
They are not proteins, and may be organic or inorganic molecules.
Both types of molecules sometimes contain a metal ion at the centre, such as Mg2+, Cu2+, Mn2+ or iron-sulphur clusters.
This is because such ions may act as electron donors, and this is important in many reactions.
The need of enzymes for various little helpers is the basic reason why animals, including ourselves, need trace elements and vitamins.
Enzymes have been classified by the International Union of Biochemistry.
Their Commission on Enzymes has grouped all known enzymes into six classes:
Oxido-reductases: catalyse transfer of electrons
Transferases: move functional group from one molecule to another
Hydrolases: add –OH (hydroxyl) group
Lyases: split chemical bonds, and often add double bond or ring structure
Isomerases: A –> B where B is an isomer of A
Ligases: join two large molecules: Ab + C –> A–C + b
The individual enzymes are given a four-figure number which classifies them in the database.p145
Uses of enzymes
making baby food - pre-digesting food for babies
softening the centres of chocolates
biological washing powder - which contains protease enzymes to break down the grime and dirt.
It breaks the large, insoluble molecules into small, soluble molecules.
It works at a lower temperature, so less energy is needed (thermostable)
A mountain is a large natural rise of the Earth's surface that usually has a "summit" (the name for a mountain's top, which can also be called a peak).
It is usually steeper and taller than a hill.
By definition, mountains are often thought of as being a hill which is higher than 600 meters (about 2,000 feet).
However, some definitions say a mountain is a hill higher than 300 meters (about 1,000 feet).
Definition of a mountain
The highest point of a mountain is called the peak.
A mountain's summit is the highest area where an individual can reach.
A mountain climber will not reach the peak of the mountain but can reach the summit.
Britannica Student Encyclopedia says that the term "mountain" usually means a rise of over 2,000 feet (610 m)".
Polytechnic Student Encyclopedia says that the term "mountain" usually means a rise of over 1,000 feet (300 m)".
The standard height for a mountain in England is 600 metres.
In England, this is important  because in English law people have the "Right to Roam" in mountains, but they do not have the same right to walk on someone-else's land.
The forming of a mountain is called orogeny.
Mountains are formed when rock layers in the ground are pushed from opposite sides, and by being pushed, they push the crust up.
A mountain range is a large group of mountains beside each other.
There are three main ways a mountain may be made:
Fold mountains
Fold mountains occur when two plates collide.
The less dense continental crust "floats" on the denser mantle rocks beneath.
The continental crust is normally much thicker under mountains, compared to lower lying areas.
Rock can fold either symmetrically or asymmetrically.
The upfolds are anticlines and the downfolds are synclines.
The Jura Mountains are an example of fold mountains.
Folded mountains make up some of the highest mountains in the world.
Folded mountains commonly form along boundaries, where 2 continents meet.
Some really complex folds are in parts of the Andes, Alps, Himalayas, Appalachians, and Russia's Ural Mountains.
These long mountain chains also show lots of signs of folding.
Block mountains
Block mountains are caused by faults in the crust: a seam where rocks can move past each other.
When rocks on one side of a fault rise relative to the other, it can form a mountain.
The uplifted blocks are block mountains or horsts.
The dropped blocks are called graben.
They can form extensive rift valley systems.
This form of landscape can be seen in East Africa, the Vosges, the Basin and Range province of Western North America and the Rhine valley.
These areas often occur when the regional stress is extensional and the crust is thinned.
Volcanic mountains
When a tectonic plate is pushed below another tectonic plate,
at a mid-ocean ridge or hotspot.
At a depth of around , melting occurs in rock above the slab (due to the addition of water), and forms magma that reaches the surface.
When the magma reaches the surface, it often builds a volcanic mountain, such as a shield volcano or a stratovolcano.
Examples of volcanoes include Mount Fuji in Japan and Mount Pinatubo in the Philippines.
The magma does not have to reach the surface in order to create a mountain: magma that solidifies below ground can still form dome mountains, such as Navajo Mountain in the states of Utah and Arizona, in the United States.
Volcanic mountains form when molten rock erupts onto the Earth's surface.
They can either form on land or in the ocean.
The Cascade Range in Washington, Oregon and northern California is made of volcanoes.
Some of the largest volcanoes are on divergent boundaries, which form the mid-ocean ridges.
The mid-ocean ridges have big volcanic mountain chains that run through the Atlantic, Pacific and Indian Oceans.
The mountains in the mid-ocean ridges can grow tall enough to create islands such as Iceland or the Azores.
Other volcanic mountains form over hot spots, pockets of magma beneath the crust which erupt onto Earth's surface.
The Hawaiian Islands are the tops of really high volcanic islands that have formed over a hot spot on the sea floor.
The main Hawaiian island is a volcano about  above the ocean floor.
Its base is about  wide.
Almost  of this island is above sea level.
Dome mountains
Dome mountains, like those in the Black Hills of South Dakota and the Adirondack Mountains of New York, are an unusual domish type of mountain that is formed when molten rock rises through the crust and push up the rock layers above it.
This creates a circular dome on the Earth's surface.
The molten rock later cools off and forms hardened rock.
When the pushed up rocks are worn away, the hardened rock is shown.
This hardened rock then wears away in places.
When it wears away, it leaves mountains, and they are called dome mountains.
Plateau mountains
Plateau mountains are formed a bit like folded mountains.
They are large areas of flat topped rocks that have been lifted high above the crust by continental plates.
Most plateaus are near folded mountains.
Tallest mountains
The highest known mountain in the Solar System is the Olympus Mons (27 km high) on Mars.
The highest mountain on earth is Mount Everest (8,848m) which is in Nepal and Tibet, in Asia.
The "tallest" mountain in the world is Mauna Loa, in Hawaii.
The "height" of a mountain is measured from sea level, but the "tallness" of a mountain is measured from its base, even if under water.
The highest mountain in North America is Mount McKinley (6,194m) in Alaska in the USA.
The highest in South America is Aconcagua (6,962m) in Argentina.
For Africa, it is Kilimanjaro (5,963m) of Tanzania.
In Europe, the highest mountain is in Russia called Elbrus (5,633m).
Antarctica's highest mountain is Vinsin Massiff (5,140m).
In Oceania, a mountain called Puncak Jaya (5,030m) is the highest there.
This particular mountain is in Papua New Guinea / Indonesia.
Machine code is a computer program written in machine language.
It uses the instruction set of a particular computer architecture.
It is usually written in binary.
Machine code is the lowest level of software.
Other programming languages are translated into machine code so the computer can execute them.
An instruction tells the process what operation to perform.
Each instruction is made up of an opcode (operation code) and operand(s).
The operands are usually memory addresses or data.
An instruction set is a list of the opcodes available for a computer.
Machine code is what assembly code and other programming languages are compiled to or interpreted as.
Machine code is sometimes called native code.
This is used when talking about things that work on only some computers.
Writing machine code
Using a number of switches.
This generates a sequence of 1 and 0.
This was used in the early days of computing.
Since the 1970s, it is no longer used.
Using a Hex editor.
This allows the use of opcodes instead of the number of the command.
Using an Assembler.
Assembly languages are simpler than opcodes.
Their syntax is easier to understand than machine language but harder than high level languages.
The assembler will translate the source code into machine code on its own.
Using a High-level programming language allows programs that use code that is easier to read and write.
These programs are translated into machine code.
The translation can happen in many steps.
Java programs are first optimized into bytecode.
Then it is translated into machine language when it is used.
Typical instructions of machine code
Arithmetical operations: Addition, subtraction, multiplication, division.
Logical operations: Conjunction, disjunction, negation.
Operations acting on single bits: Shifting bits to the left or right.
Operations acting on memory:  copying a value from one register to another.
Operations that compare two values: bigger than, smaller than, equal.
Operations that combine other operations: add, compare, and copy if equal to some value(as one operation), jump to some point in the program if a register is zero.
Operations that act on program flow: jump to some address.
Operations that convert data types: e.g. convert a 32-bit integer to a 64-bit integer, convert a floating point value to an integer (by truncating).
Many modern processors use microcode for some of the commands.
More complex commands tend to use it.
This is often done with CISC architectures.
Every processor or processor family has its own instruction set.
Instructions are patterns of bits that correspond to different commands that can be given to the machine.
Thus, the instruction set is specific to a class of processors using (mostly) the same architecture.
Newer processor designs often include all the instructions of a predecessor and may add additional instructions.
Sometimes, a newer design will discontinue or alter the meaning of an instruction code (typically because it is needed for new purposes), affecting code compatibility; even nearly completely compatible processors may show slightly different behavior for some instructions, but this is rarely a problem.
Systems may also differ in other details, such as memory arrangement, operating systems, or peripheral devices.
Because a program normally relies on such factors, different systems will typically not run the same machine code, even when the same type of processor is used.
Most instructions have one or more opcode fields.
They specify the basic instruction type.
Other fields may give the type of the operands, the addressing mode, and so on.
There may also be special instructions that are contained in the opcode itself.
These instructions are called immediates.
Processor designs can be different in other ways.
Different instructions can have different lengths.
Also, they can have the same length.
Having all instructions have the same length can simplify the design.
The MIPS architecture has instructions which are 32 bits long.