The Lie derivation of multivector fields along multivector fields has been introduced by Schouten (see [10, 11]), and studdied for example in [5] and [12]. In the present paper we define the Lie derivation of differential forms along multivector fields, and we extend this concept to covariant derivation on tangent bundles and vector bundles, and find natural relations between them and other familiar concepts. Also in spinor bundles, we introduce a covariant derivation along multivector fields and call it the Clifford covariant derivation of that spinor bundle, which is related to its structure and has a natural relation to its Dirac operator.

The type of the applications for which Internet is being used has changed over the years. Multimedia applications, Real-time applications and Game playing require Quality of service. IEEE has proposed IEEE 802.11e, a quality of service extension to the wireless LAN standard IEEE 802.11. In this paper service DIFFERENTIATION ability of 802.11e is evaluated. Identical traffic is considered for all Access categories to quantitatively differentiate different Access categories. The results indicate, 802.11e achieves service DIFFERENTIATION with some limitations. NS-2.26 is used for simulation.

Reproduction in domestic animals, as a major source of food and other products for human, as great importance and study of related subjects including sex DIFFERENTIATION and gonadogenesis during fetal life can solve many questions on normal development and various disorders of urogenital system. Since studies on sex DIFFERENTIATION in goat fetus are scarce, this study was performed. Twenty-five goat fetuses with 5–40 mm crown-rump lengths (CRL) were obtained from slaughter-house and fixed in 10% formalin solution immediately. The development and features of external genitalia of these fetuses as well as their sex DIFFERENTIATION were then examined. In externally indifferentiated fetuses, the cranial half of the body was cut away at the diaphragmatic level and serial sections, 6-micron thickwere prepared and the ovarian and testicular DIFFERENTIATION was studied. Results showed that considering the development of the external genitalia, external sex DIFFERENTIATION occurs at 31 mm CRL in male fetuses and at 33 mm CRL in female fetuses. Microscopic studies suggested that testicular tissue DIFFERENTIATION occurs at 23 mm CRL with formation of tunica albuginea and medullary cords. Ovarian tissue DIFFERENTIATION occurs at 38 mm CRL with establishment of cortical and medullary regions.