Engel groups and Engel elements became popular in 50s. We consider in the paper the more general nil-groups and nil-elements in groups. All these notions are related to nilpotent groups and nilpo-tent radicals in groups. These notions generate problems which are parallel to Burnside problems for periodic groups. The first three theorems of the paper are devoted to nil-groups and Engel groups, w...

BACKGROUND Outcome following epilepsy surgery has traditionally been measured in terms of relief of seizures. However, changes in health-related quality of life (HRQOL) after surgery for intractable epilepsy are also important to document. There are no studies on the Indian population which assess the outcome of epilepsy surgery in terms of HRQOL. MATERIALS AND METHODS We conducted a prospect...

Megalopta Smith, 1853, is a Neotropical genus of nocturnal or crepuscular bees. Two subgenera are recognized with most of its nearly 30 species placed in the nominate subgenus. Species of Megalopta s. str. are more commonly collected than species of Noctoraptor Engel et al. 1997, all presumably parasites of Megalopta s. str. Two new species of Megalopta are described here: M. (Megalopta) tetewa...