Monozygotic twinning occurs in birthing at a rate of about three in every 1000 deliveries worldwide.

North American dizygotic twinning occurs about once in 83 conceptions, and triplets about once in 8000 conceptions.

Crystal twinning occurs when two separate crystals share some of the same crystal lattice points in a symmetrical manner.

Merohedral twinning occurs when the lattices of the contact twins superimpose in three dimensions, such as by relative rotation of one twin from the other.

When twinning occurs

Half-identical or semi-identical twins ( also referred to as " half twins ") are the result of a very rare form of twinning in which the twins inherit exactly the same genes from their mother but different genes from their father.

" TV Guide gave the film one star out of four, noting that it " suffers from some very dicey twinning effects when the brothers are in frame together.

The twinning charter was signed in 1994, but very little twinning activity takes place.

The twinning only lasted some 15 years and, after growing disputes between the Menotti family and the Spoleto Festival USA board, in the early ' 90s a separation was consummated.

Its early success ensured that, after local government reorganisation in both countries in the mid-seventies, the twinning was taken over by the new Councils of Märkischer Kreis and Wrexham Maelor Borough Council and, in 1996, by Wrexham County Borough Council.

As a precursor to the upcoming twinning project, the customs and toll collection booths on both sides were extensively reconfigured in the early 1990s.

Another early example of town twinning dates back to 1947 when Bristol Corporation ( later Bristol City Council ) sent five ' leading citizens ' on a goodwill mission to Hanover.

In the early 2000s the school set up a twinning with a School in the United Kingdom, Manningtree Highschool.

There is one test based on " Brazil law twinning " ( a form of quartz twinning where right and left hand quartz structures are combined in a single crystal ) which can be used to identify synthetic amethyst rather easily.

The City of Edinburgh has entered into 11 international twinning arrangements since 1954.

In an optical mineralogy analysis, thin sections of rock samples are analyzed through a petrographic microscope, where the minerals can be identified through their different properties in plane-polarized and cross-polarized light, including their birefringence, pleochroism, twinning, and interference properties with a conoscopic lens.

The twinning agreements include co-operation in the fields of culture, education and industry.

The sources of the stresses include deformation ( e. g. an increase in pressure ), exsolution, or twinning.

Crystal twinning is common in feldspars, especially polysynthetic twins in plagioclase and Carlsbad twins in alkali feldspars.

The party has close links with Plaid Cymru ( their partner in the EFA ) including a twinning arrangement with Plaid's Blaenau Gwent branch, and to a lesser extent with the SNP.

A number of cities around the world ( especially those which had suffered similar wartime devastation ) established sister / friendship / twinning links ( see list below ) in the spirit of solidarity or reconciliation.

The crystal should be sufficiently large ( typically larger than 0. 1 mm in all dimensions ), pure in composition and regular in structure, with no significant internal imperfections such as cracks or twinning.

Crystals can be marred by twinning, which can occur when a unit cell can pack equally favorably in multiple orientations ; although recent advances in computational methods may allow solving the structure of some twinned crystals.

Feldspar within a pegmatite may display exaggerated and perfect twinning, exsolution lamellae, and when affected by hydrous crystallization, macroscale graphic texture is known, with feldspar and quartz intergrown.

The city of Poznań has international twinning arrangements with the English county of Nottinghamshire.

Zakopane participates in town twinning to foster international links.

Until this point in development, twinning is possible.

In the 1960s, Turku became the first Western city to sign a twinning agreement with Leningrad in the Soviet Union, leading to greater inter-cultural exchange and providing a new meaning to the city's ' gateway ' function.

This muddy situation possibly originated from the indirect nature of the experimental evidence, as well as experimental issues such as sample quality, impurity scattering, twinning, etc.

Other important investments that have helped position Sydney as an eastern hub of Nova Scotia include the twinning of Highway 125 and the creation of the Centre for Sustainability in the Environment at nearby Cape Breton University, which draws hundreds of international students each year.

There are plans for further twinning of the highway from Lake Louise to Kamloops, although a completion date has not been set.

It turns out the ' twinning ' of Bideford with Manteo had been established 20 years before.

The Yoruba have the highest rate of twinning in the world, at 45-50 twin sets ( or 90-100 twins ) per 1, 000 live births, possibly because of high consumption of a specific type of yam containing a natural phytoestrogen which may stimulate the ovaries to release an egg from each side.

The world's highest rates of twinning are found across Central Africa, where there are 18-30 twin sets ( or 37-62 twins ) per 1, 000 live births.

Now time is also the concern of the fictional narrative, which is, at its simplest, the story of an action with, usually, a beginning, a middle, and an end -- elements which demand time as the first condition for their existence.

Body integrity identity disorder is a psychological condition in which an individual feels compelled to remove one or more of their body parts, usually a limb.

During thelarche, the developing breasts sometimes are of unequal size, and usually the left breast is slightly larger ; said condition of asymmetry is transitory and statistically normal to female physical and sexual development.

A condition identified as Borzoi Retinopathy is seen in some individuals, usually active dogs, which differs from progressive retinal atrophy in several ways.

Calves are usually weaned at about eight to nine months of age, depending on the season and condition of the dam, they might be weaned earlier.

The group maintains two inventories of " Heritage pubs ", the National Inventory ( NI ), which contains only those pubs that have been maintained in their original condition ( or have been modified very little ) for at least 30 years, but usually since at least World War II.

Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones ( congenital hypothyroidism ) usually due to maternal hypothyroidism.

Concubinage is an interpersonal relationship in which a person engages in an ongoing relationship ( usually matrimonially oriented ) with another person to whom they are not or cannot be married ; the inability to marry is usually due to a difference in social status or economic condition.

( Although mutual orthogonality is the only condition, these vectors are usually constructed for ease of decoding, for example columns or rows from Walsh matrices.

During this time, Munch received many commissions for portraits and prints which improved his usually precarious financial condition.

They are often portrayed as children with Williams syndrome ( which was not recognised as a medical condition but some specialist believe that people were enchanted with their character and appearance that they believed to be magical ), usually with fair hair.

This condition carries a good prognosis because children do not usually show cognitive decline or neurological deficits, and the seizures in the majority cease spontaneously with onging maturation.

Fluoroquinolones are not recommended as first-line antibiotics for acute sinusitis, as this condition is usually self-limiting, and the risks outweigh the benefits in comparison to other antibiotic classes.

This is a condition where atypical blood vessels proliferate usually in a radially symmetric pattern around the pylorus of the stomach.

Although this condition does not otherwise harm a person's health, it is disfiguring and usually permanent.

Continuity of the balls ' condition is considered part of the game, so if a re-warm-up is required after an extended break in play ( usually due to rain ), then the re-warm-up is done using a separate set of balls, and use of the match balls is resumed only when play resumes.

The definitions that we have given here are the ones usually used today ; however, some authors switch the meanings of the two kinds of terms, or use all terms synonymously for only one condition.

When some effort at fulfilling some reparation condition fails, it must be repeated, usually by someone else after some intervening time-period ; history therefore exhibits a cyclic pattern.

The mutant condition that is often kept secret from the world can be analogous to feelings of difference and fear usually developed in everyone during adolescence.

Plutarch also states that Spartans treated the Helots " harshly and cruelly ": they compelled them to drink pure wine ( which was considered dangerous – wine usually being cut with water ) "... and to lead them in that condition into their public halls, that the children might see what a sight a drunken man is ; they made them to dance low dances, and sing ridiculous songs ..." during syssitia ( obligatory banquets ).

( In British usage, ASA and AAS are usually combined into a single condition AAcorrS-any two angles and a corresponding side.

This condition, however, usually results in spontaneous miscarriage in the first trimester.

An " escrow agent " is one kind of trustee who is a stakeholder, usually in a situation where part of the purchase price of property is being held until some condition is satisfied.

Doing so duplicates the condition check ( increasing the size of the code ) but is more efficient because jumps usually cause a pipeline stall.