Regarding spontaneous or natural monozygotic twinning, a recent theory posits that monozygotic twins are formed after a blastocyst essentially collapses, splitting the progenitor cells ( those that contain the body's fundamental genetic material ) in half, leaving the same genetic material divided in two on opposite sides of the embryo.

This situation is not the same as the common form of fraternal twinning, in which two genetically different ova are fertilized by two genetically different sperm.

In 1992 a twinning agreement was reached with the Finsterwalde District of Brandenburg, unofficial relations between the two districts having existed since German reunification in 1990.

Factors influencing a crystal's habit include: a combination of two or more crystal forms ; trace impurities present during growth ; crystal twinning and growth conditions ( i. e., heat, pressure, space ); and specific growth tendencies like growth striations.

Plasticity in a crystal of pure metal is primarily caused by two modes of deformation in the crystal lattice, slip and twinning.

On 2 July 2005, two trees were planted to the north of the town hall to mark the 20th anniversary of the twinning between Yarm and the two towns.

* In animation, twinning refers to when two parts on opposite sides of a character's body move the same way

The mayor of Les Martres-de-Veyre proposed to honour the dead Canadian soldier through the twinning of their two small towns and the creation of a new large memorial at his gravesite.

* Town twinning or sister cities: two distant cities or towns agree to partner each other, for various reasons.

Note also that any twinning arrangement should be listed at two locations in the list: once for each of the towns involved in the arrangement.

This twinning operation was made possible by the partnership between the two Mayors.

Links between the two towns have their roots in the 1980s and the official ratification and twinning ceremony took place in 2002.

The twinning charter is written in Irish, English and French, and it commits the two towns to " developing social, economic, cultural, touristic, and sporting links " between the two communities.

The upgrade to Highway 416 took place between 1989 and 1999 and was carried out through two separate projects: Highway 416 North was a freeway on a new alignment through Ottawa and an interchange at Highway 417, and Highway 416 South was the twinning of of Highway 16 New and an interchange at Highway 401.

Their finest hour was when they met two German people of much the same nature when attending a celebration of a twinning of two towns.

Most universities, including many who offer " twinning " courses with local private colleges, outside these two countries do not consider MUET as an acceptable test for English language proficiency, preferring instead, the IELTS. However, in recent times, the MUET has lost its prominence as a requirement to be admitted into local universities, be it public or private ones.

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

In the 1960s, several exchange visits between the two towns took place, but the twinning formally ceased as a consequence of Dalum being absorbed by the much larger Odense.

With the twinning of the Blue Mountain, Kittatinny Mountain and Tuscarora Mountain tunnels under construction, the Commission turned its focus to the remaining two mainline tunnels, the Rays Hill Tunnel ( the shortest tunnel ) and the Sideling Hill Tunnel ( the longest tunnel ).

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.

The authors were unable to predict whether a healthy fetus could result from a polar body twinning.

The twinning is a result of Cornish migration during the Californian gold rush in which Cornish mining expertise was exported to the area.

Deformation twinning is a common result of regional metamorphism.

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.