Down syndrome comes from a problem with the genes. Humans are diploid organisms. This means that for each chromosome, there are two copies, one from the mother, and one from the father. During meiosis the number is reduced to one set of chromosomes. People with Down syndrome have an extra copy of chromosome 21, or part of it.
There are three ways that Down syndrome is caused. The most common cause of Down syndrome is trisomy. Trisomy is when the child receives two chromosomes from the mother and one from the father. This makes it so there are three chromosomes of chromosome #21. Another way Down syndrome is caused is when new cells are made. Sometimes even when the parent cells are normal chromosome 21 can be deformed when cells reproduce. This makes it so some cells have 47 chromosomes and others have 46. This is called a mosaic disorder. Mosaic means that they have a third chromosome from the replication of cells. The third way Down syndrome can be caused is called translocation. This happens when a normal chromosome breaks into two pieces. This results in three chromosomes.
For comprehensive lists of Down syndrome links see
By Country
Genetic disorder
A genetic disorder is an illness caused by abnormalities in the genome. They are heritable, and are passed down from the parents' genes. If a genetic disorder is present from birth, it is a type of congenital defect. Some only show up in later life. Genetic disorders, like other illnesses, can cripple and kill.
Most genetic disorders are quite rare and affect one person in every several thousands or millions. Sometimes they are relatively frequent in a population. These types of recessive gene disorders give an advantage in certain environments when only one copy of the gene is present. Sickle cell anaemia is an example.
The same disease, such as some forms of cancer, may be caused by an inherited genetic condition in some people, by new mutations in other people, and by nongenetic causes in still other people. A disease in only called a genetic disease when it is inherited.
Umberto Eco
Umberto Eco (January 5, 1932 – February 19, 2016) was an Italian writer and professor of medieval history in Bologna.
Eco was born in 1932 in northern Italy.
As a student, he studied philosophy, history, literature, and .
He finished his studies in 1954 with a doctoral thesis about Thomas Aquinas. In 1962, he married.
His career as a author began with "" in 1980, after he already written many academic papers.
Eco was born on January 5, 1932 in Alessandria. His family had 13 sons. He studied philosophy and humanities at the . He received a Ph.D. there.
Eco worked as a professor in different places. Starting in 1971, he held the chair of semiotics at the University of Bologna. At a university, a "chair" is the highest rank a professor can earn. He was also given honorary degrees by thirty different universities.
He had been named satrap of for his humorous works. One of his most important books is "How to Travel with a Salmon."
He was a member of UNESCO's Council of Sages. In 2000, he received the for Communications and Humanities.
Eco worked in the mass media as well, creating cultural programs. His interests were the Middle Ages, languages, and the classics. He was also an expert on James Bond.
On February 19, 2016, Eco died at his home in Milan, Italy, of pancreatic cancer. He was 84.
Balloon
A balloon is a bag that is usually filled with gas. This gas can be helium, hydrogen, or air.
A long time ago, balloons were made out of animal bladders. Now small balloons are made from a thin and stretchy material like rubber or plastic. Big balloons are made from fabric.
Balloons are used for many purposes.
Most small balloons are made for parties. These balloons are sometimes made to look like animals.
Some balloons are very big. Big balloons are used for people to fly into the sky. Big balloons are called aircraft. Most balloon aircraft are filled with hot air. They are called hot air balloons.
Balloons can also be filled with water. They are called "water balloons". Water balloons are a kind of toy.
AM
AM may refer to:
Einsteinium
Einsteinium is a chemical element with the atomic number 99. That means an Einsteinium atom has 99 protons and 99 electrons.
It is a synthetic element, so all isotopes are radioactive.
Einsteinium belongs to the actinoids, and it is the 7th of them. The most stable isotope of Einsteinium has 99 protons and electrons and 153 neutrons. There are 19 different (radioactive) isotopes.
Einsteinium is named after Albert Einstein. It was found for the first time in 1952 by Albert Ghiorso and his team of scientists in the debris of the first hydrogen bomb explosion, and identified as an element at the University of California, Berkeley.
Einsteinium isotopes have a half-life between 40 and 471 days. Einsteinium has been used to create the element Mendelevium for the first time, in 1955, although no practical uses are known.
Vulva
The vulva is the part of the body of female mammals (including women) where the outside parts of the reproductive system can be seen. The parts of the vulva that can be seen are the:
The mons pubis is the area of skin and fat above the other structures. It protects the other structures below it. The labia majora are thick areas of skin and fat located to the side of the urinary and vaginal openings. Smaller and thinner labia are the labia minora. These structures are connected to the hood of the clitoris . They are close to the vagina. Many people call the vagina when they mean the vulva. The vagina is the "tube" connecting the internal parts (the womb) to the vulva.
Congruence
In geometry, two figures or objects formula_1 and formula_2 are congruent (written as formula_3) if they have the same shape and size, or if one has the same shape and size as the mirror image of the other.
More formally, two sets of points are called congruent, if and only if one can be transformed into the other by isometry. For isometry, "rigid motions" are used.
This means that two geometrical figures are congruent if one object can be repositioned, rotated or reflected—but not resized—so that it coincides exactly with the other object. if one can be moved or rotated so that it fits exactly where the other one is, then the two figures are congruent. If one of the object has to change its size, then the two objects are not congruent: they are just called similar.
As an example, two distinct plane figures on a piece of paper are congruent if we can cut them out and then match them up completely (turning the paper over here is permitted).
Congruent polygons are polygons that if you fold a regular polygon in half that is a congruent polygon.
The following are a few rules to make new shapes congruent to the original one:
The relationship, that "a shape is congruent to another shape", has three famous properties:
The famous three properties, "reflexivity", "symmetry" and "transitivity", together make the notion of "equivalence". Hence, the property congruence is one sort of "equivalence" relation between shapes of a plane.
Deism
Deism is the belief that a higher being (like the Christian God) exists, but that the only revelation of God is in nature and reason, not in sacred books or prophets. Deism says that people should rely on logic and reason, and not traditions of a religion that is based on a holy book. People who follow deism are called deists.
Deists believe that a Higher Power created the world. They do not believe that the creation of the universe happened because of a spontaneous event. They usually reject supernatural events like miracles, and believe that God has set up natural laws, which govern how the universe works and how people should act, and does not interfere with these laws. Most deists also see holy books, such as the Bible and Qur'an, as writings made by people, rather than the writings of God.