For each clone C on a set A there is an associated equivalence relation, called C-equivalence, on the set of all operations on A, which relates two operations iff each one is a substitution instance of the other using operations from C. In this paper we prove that if C is a discriminator clone on a finite set, then there are only finitely many C-equivalence classes. Moreover, we show that the s...

Every operation or relation on a base set A can be "lifted" to the power set P ( A ) . In this paper clones of operations and corresponding invariant relations are studied under this process of lifting (e.g. the clone generated by all lifted operations of a clone is characterized internally by 6-closure (Thm. 2.2) and externally by special invariant relations (Thm. 2.4, 3.3)). Generalizations t...

abstract east azarbaijan province is one of the most important areas for poplar production and has the highest suitability of poplar plantation in iran. three species of poplar trees included populus alba, p. nigra and p. x. euramericana are planted and usually attacked by different pests in this province. melasoma populi l., archips rosana (l.) and pemphigus filaginis are some of important pes...

For each clone C on a set A there is an associated equivalence relation analogous to Green’s R-relation, which relates two operations on A if and only if each one is a substitution instance of the other using operations from C. We study the maximal and submaximal clones on a three-element set and determine which of them have only finitely many relative R-classes.

Drawing upon our knowledge of microbial genetics, Burnet has proposed a theory of antibody formation which offers an explanation for certain poorly understood immunologic phenomena (for example, the persistence of antibody for long periods in the absence of contact with the antigen, and the failure to form antibodies to self-antigens under normal conditions). According to Burnet's hypothesis, a...

The effects of drought simulated via osmotic stress induced by polyethylene glycol (PEG) in the growing medium were examined on two Wild cherry (Prunus avium L.) clones (6A and 8A) based thirteen morphometric, physiological, biochemical traits. shoot tips exposed to PEG concentrations (20 50 g L-1) designed for micropropagation with axillary buds. results showed that all morphological physiolog...

Drawing upon our knowledge of microbial genetics, Burnet has proposed a theory of antibody formation which offers an explanation for certain poorly understood immunologic phenomena (for example, the persistence of antibody for long periods in the absence of contact with the antigen, and the failure to form antibodies to self-antigens under normal conditions). According to Burnet's hypothesis, a...

Poly(A)+ RNA isolated from the developing wheat endosperm var. Chinese Spring, has been used as template for the construction of a cDNA library. Within the library, clones have been identified by in vitro translation of hybrid-selected mRNA which encode alpha/beta gliadin related sequences and gamma-gliadin related sequences. The DNA sequence of one such clone has been determined and it shows h...

We prove that every clone of operations on a finite set A, if it contains a Malcev operation, is finitely related – i.e., identical with the clone of all operations respecting R for some finitary relation R over A. It follows that for a fixed finite set A, the set of all such Malcev clones is countable. This completes the solution of a problem that was first formulated in 1980, or earlier: how ...