Oscillation criteria are obtained for all solutions of the first-order linear delay differential equations with positive and negative coefficients where we established some sufficient conditions so that every solution of (1.1) oscillate. This paper generalized the results in [11]. Some examples are considered to illustrate our main results.

     The specimens of Camponotusxerxes Forel, 1904 were collected from different localities in Iraq; the purpose of morphological study of this species in details throughout the present study.

     The description was based on major workers belonging to this species, also some notes of polymorphism in workers have been mentioned; the most important of morphological features are illustrated and figured.

In this research some new nucleoside analogues were synthesized. Starting from α-D- glucose which was protected to glucose penta acetat α-D- glucose pyronside (1). Which was converted to active form 1-bromo protected sugar (2) as a sugar moiety. The base moiety 2-substituted imidazoline (3,4) was prepared from condensation of ethylene diamine with two kind of aromatic aldehydes, which were subjected to amino alkylation via Mannich reaction forming new nucleaobase derivatives (5-10). Condensation of nucleobase with bromo sugar through nucleophilic substitution of anomeric carbon with nitrogen forming new protected nucleoside analogues (11-16). De blocking of these nucleoside analogues with sodium methoxide in methanol afforded our targe

The effect of micro-and nano silica particles (silica SiO2 (100 μm), Fused silica (12nm)) on some mechanical properties of epoxy resin was investigated (Young's modulus, Flexural strength). The micro-and nano composites were prepared by using three steps process with different volume fraction of micro-and nano particles (1, 2, 3, 4, 5, 7, 10, 15, and 20 vol. %). Flexural strength and Young's modulus of nano composites were increased at low volume fraction (max. enhancement at 4 vol.% ). However at higher volume fraction both Young's modulus and flexural strength decrease. Moreover, above, the mechanical properties are enhanced more than that of neat epoxy resin. The flexural strength decreases with increasing the volume fraction of micr

In this paper an eco-epidemiological system has been proposed and studied analytically as well as numerically. The boundedness, existence and uniqueness of the solution are discussed. The local and global stability of all possible equilibrium point are investigated. The global dynamics is studied numerically. It is obtained that system has rich in dynamics including Hopf bifurcation.