E-learning systems are tremendously popular. Lifelong learning, learning anytime and anywhere are one of most effective slogans for pushing distance learning. Unfortunately, the promises that all learners benefit from elearning could not be kept. The amount of frustrated, un-motivated users is quite huge proved by high drop out rates. Despite enormous efforts to provide high-level multimedia le...

In this paper we prove that every finitely generated Coxeter group has a finite index subgroup that is the fundamental group of a special cube complex. Some consequences include: Every f.g. Coxeter group is virtually a subgroup of a right-angled Coxeter group. Every word-hyperbolic Coxeter group has separable quasiconvex subgroups. © 2010 Elsevier Inc. All rights reserved. MSC: 53C23; 20F36; 20...

from your own language. The result would most probably be disastrous. However: better used at the beginning of a sentence followed by a comma. Avoid writing however in the middle of a sentence, where badly used commas can cause all sorts of problems. Impact factor: we all know what this is, but a journal with high impact factor is not necessarily your best bet when you want to publish a paper. ...