In this paper we obtain oscillation criteria for solutions of homogeneous and nonhomogeneous cases of second order neutral differential equations with positive and negative coefficients. Our results improve and extend the results of Manojlović, Shoukaku, Tanigawa and Yoshida [6].

Cognitive development is a process from an initial knowledge state at birth to a later mature one. The problem of developmental psychology is to describe and explain the intricacies of this process. In “The Scientist in the Crib”, Alison Gopnik, Andrew N. Meltzoff and Patricia K. Kuhl approach this problem from the perspective of one theory in developmental psychology — the theory theory. The b...

Good symmetric encryption schemes as well as randomization and hashing techniques are based on effective techniques of confusion and diffusion [1]. Quasigroups provide an excellent way to generate an astronomical number of keys and therefore they are excellent at confusion [2] but they are not equally good at diffusing the statistics of the plaintext. Specifically, the quasigroup transformation...

In 1987, Mitsuaki Yoshida proposed the following model (Yoshida and Seiki, 1987): "... T-cells activated through the endogenous p40x would express viral antigens including the envelope glycoproteins which are exposed on the cell surface. These glycoproteins are targets of host immune surveillance, as is evidenced by the cytotoxic effects of anti-envelope antibodies or patient sera. Eventually a...