Disconnection motion along (10
12) and (11
21) twins in Zr is investigated
using atomic-scale simulation. In particular, the high mobility of glissile disconnections
is studied in terms of the atomic shears and shuffles involved.
Using a quasi-static simulation procedure, the displacements of individual
atoms are followed as they transit from matrix sites, through interfacial sites,
and hence to twin sites by repeated passages of disconnections along the interface.
It is found that the overall displacements for the cases studied are those
predicted by the Bilby and Crocker (1965) theory which invokes homogeneous
shear deformation. However, the present work enables atomic tracks to
be followed through the cores of moving disconnections. The combinations of
shears and shuffles in the two twinning systems are found to be quite distinct.
In addition to tracking their coordinates, the variation of hydrostatic pressure
experienced by the atoms is also quantified.

The pesticides have different adverse impacts on different life stages of fish species with attempts to
use dietary antioxidants to counteract their effects. So, the present study investigated the potential
protective effects of vitamin E (50 mg/kg BW), tomato paste (in terms of 9 mg lycopene/kg BW) and their
combination versus atrazine-induced changes in Clarias gariepinus. This species were exposed to
sublethal doses of atrazine of 1.7 and 3.4 mg/L for 15 and 30 days. Atrazine significantly (P<0.05)
induced free radicals in serum constituents. It caused a significant (P<0.05) increase in serum glucose,
mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and lipid peroxidation in liver.
Addition of vitamin E and/or tomato paste to the diet of atrazine-treated fish improved the serum
glucose, MCV, MCH and LPO levels in comparison to control fish. On the other hand, atrazine
significantly (P<0.05) led to decline in serum total protein, total lipid, blood hemoglobin, total
erythrocytes count, packed cell volume, and mean corpuscular hemoglobin concentration.These
atrazine-induced parameters were improved with the dietary supplemented tomato paste and/or vitamin
E.