منابع مشابه
Dizygotic twinning.
The tendency to conceive spontaneous dizygotic (DZ) twins is a complex trait with important contributions from both environmental factors and genetic disposition. Twins are relatively common and occur on average 13 times per 1000 maternities, though the twinning frequency varies over time and geographic location. This variation is mostly attributed to the differences in DZ twinning rate, since ...
متن کاملTwinning in cattle.
INTRODUCTION The biological efficiency of traditional systems of beef production is low due to the low reproductive rate and the high proportion of total energy which is required for maintenance of the breeding herd. Dickerson (1978) estimated that 56% of the total feed energy intake for adult and market cattle is required solely for body maintenance (the non-productive energy requirement rises...
متن کاملTwinning rates in Tamilnadu.
A prospective study of human reproduction was conducted in Tamilnadu State, South India, from 1969 to 1975. This paper reports twinning rates and relates these to maternal age, parity, and consanguinity. Birth weights and other dimensions at birth and infant mortality are also studied. The overall twinning rate was 1 in 115 births. Dizygotic twinning rates increased significantly with maternal ...
متن کاملMagnetron Frequency Twinning
Pulsed magnetron oscillators sometimes show an instability known as “twinning” in which the spectrum shows two, or more, closely spaced peaks. This phenomenon is undesirable and can lead to problems when it occurs in magnetrons used in radars. An experimental investigation of twinning is described from which conclusions are drawn about the design parameters that affect it. It has been shown tha...
متن کاملTwinning-like lattice reorientation without a crystallographic twinning plane
Twinning on the plane is a common mode of plastic deformation for hexagonal-close-packed metals. Here we report, by monitoring the deformation of submicron-sized single-crystal magnesium compressed normal to its prismatic plane with transmission electron microscopy, the reorientation of the parent lattice to a 'twin' lattice, producing an orientational relationship akin to that of the conventio...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section A Foundations of Crystallography
سال: 2005
ISSN: 0108-7673
DOI: 10.1107/s0108767305094894