In merohedric twinning, the lattices of the individuals are perfectly overlapped and the presence of twinning is not easily detected from the diffraction pattern, especially in the case of inversion twinning (class I). In general, the investigator has to consider three possible structural models: a crystal with space-group type H and point group P, either untwinned (H model) or twinned through ...

Utilizing first-principles atomistic simulations we present a twin nucleation model based on the Peierls–Nabarro formulation. We investigated twinning in several important shape memory alloys, starting with Ni2FeGa (14M modulated monoclinic and L10 crystals) to illustrate the methodology, and predicted the twin stress in Ni2MnGa, NiTi, Co2NiGa, and Co2NiAl martensites, all of which were in exce...

A genetic correlation near unity between ovulation rate in heifers and later twinning frequency led to consideration of using measures of ovulation rate in heifers for each estrous cycle, beginning at puberty, to increase accuracy of selection for twinning rate. An initial evaluation with a multiple trait animal model for predicting breeding values included six genetic groups: 1) selected Scand...

Twinning in cattle is a complex trait that is associated with economic loss and health issues such as abortion, dystocia, and reduced calf survival. Twinning-rate QTL have been detected previously on BTA5 in the North American Holstein and Norwegian dairy cattle populations and in a USDA herd selected for high twinning rate. In previous work with the North American Holstein population, the stro...

microstructural evolutions of twinning induced plasticity (twip) steel during tensile straining wereinvestigated by in situ sem observations. the results indicated that slip lines and mechanical twins aswell as surface relief were increased with increasing strain, resulting in a stepped surface. additionally,these deformation mechanisms could change the shape of each grain via shear and rotatio...

Coarse-grained limestone samples were collected across the Hudson Valley Fold-Thrust Belt with the aim of determining the temporal and spatial relationship between calcite twinning strain and fold-thrust belt development. The majority of the samples have well defined oblate strain ellipsoids with the maximum shortening axes (e3) perpendicular to bedding strike, and e3 magnitudes that range from...

BACKGROUND/OBJECTIVES Multiple pregnancies have tripled in the United States over the past 3 decades. Attributed to increasing maternal age at delivery but more so assisted reproductive technological advances, an effort has been made to decrease twinning through elective single embryo transfer. We sought to review and evaluate risks of monochorionic twinning as a predictable consequence of incr...

A loss of function mutation in growth differentiation factor 9 (GDF9) in sheep causes increased ovulation rate and infertility in a dosage-sensitive manner. Spontaneous dizygotic (DZ) twinning in the human is under genetic control and women with a history of DZ twinning have an increased incidence of multiple follicle growth and multiple ovulation. We sequenced the GDF9 coding region in DNA sam...

Embryo development in plants initiates following the transverse division of a zygote into an apical, proembryo cell and a basal cell that gives rise to the suspensor. Although mutants affected in embryo development through changes in cell division have been described, little is known about the control of the first zygotic division that gives rise to the proembryo. Ascorbic acid (Asc) promotes c...

Deformation twinning from grain boundaries is often observed in face-centered cubic metals with low stacking fault energy. One of the possible factors that contribute to twinning origination from grain boundaries is the intergranular interactions during deformation. Nonetheless, the influence of mechanical interaction among grains on twin evolution has not been fully understood. In spite of ext...