The binary and ternary codes spanned by the rows of the point by block incidence matrices of some 2-designs and their complementary and orthogonal designs are studied. A new method is also introduced to study optimal codes.

A t-Cayley hypergraph X = t-Cay(G; S) is called normal for a finite group G, if the right regular representationR(G) of G is normal in the full automorphism group Aut(X) of X. In this paper, we investigate the normality of t-Cayley hypergraphs of abelian groups, where S < 4.

In order to evaluate the informal wheat seed contamination with seed-bornediseases, two most important provinces (East Azarbaijan and Khorasan Razavi) forwheat production were selected in cold region of Iran in 2008-2009 crop seasonsand ten different locations (city or village) were considered in each province andten informal seed farmers were selected randomly. A seed sample (1 kg) was takenfr...

Let $R$ be an arbitrary ring and $T$ be a submodule of an $R$-module $M$. A submodule $N$ of $M$ is called $T$-small in $M$ provided for each submodule $X$ of $M$, $Tsubseteq X+N$ implies that $Tsubseteq X$. We study this mentioned notion which is a generalization of the small submodules and we obtain some related results.

Three new records of Tanacetum L., namely, T. punctatum and T. zahlbruckneri from Azerbaidjan and T. vulgare from Mazandaran Provinces are reported for the first time from Iran. Illustrations and distribution map are also presented for each species.