The interplay between aromaticity and hydrogen bonding in 1,3-dihydroxyaryl-2-aldehydes is investigated by means of quantum-chemical calculations. The position of the extra ring formed by substituents interacting through the hydrogen bond (HB) is found to influence both the strength of the HB and the local aromaticity of the polycyclic aromatic hydrocarbon (PAH) skeleton. The HBs are stronger a...

A new characteristic property of von Neumann regular rings is proposed in terms of annihilators of elements. An ELT fully idempotent ring is a regular ring whose simple left (or right) modules are either injective or projective. Artinian rings are characterized in terms of Noetherian rings. Strongly regular rings and rings whose two-sided ideals are generated by central idempotents are characte...

The research program of Karl Ernst von Baer (1792-1876) intended to enhance the comparative approach of animal classification by demonstrating vertebrate affinities (homology). Baer visualized his ideas on development and evolution with an unpublished figure of a branching tree. To buttress his reflections on how species-specific embryogenesis produces a branching tree, he worked out a cladogra...

This paper is a continuation of our recent joint work with K.H. Leung on the real spectrum of a noncommutative ring 15]. The object of the present paper is to develop a theory of real places and valuations to accompany the theory of orderings developed in 15]. Because of the existence of integral domains which are not embeddable in a skew eld, it is necessary to deal directly with integral doma...

BACKGROUND Transient evoked otoacoustic emissions (TEOAE) are widely used for human neonatal deafness screening, but have not been reported for clinical use in dogs. HYPOTHESIS/OBJECTIVES To investigate the feasibility of TEOAE testing in conscious puppies and the ability of TEOAE testing to correctly identify deaf and hearing ears, as defined by brainstem auditory evoked response (BAER). A...

This paper studies the multiplicative ideal structure of commutative rings in which every finitely generated ideal is quasi-projective. Section 2 provides some preliminaries on quasi-projective modules over commutative rings. Section 3 investigates the correlation with well-known Prüfer conditions; namely, we prove that this class of rings stands strictly between the two classes of arithmetical...

Let n | m be positive integers with the same prime factors, such that p3 | n for some prime p. We construct a noncrossed product division algebra D with involution ∗, of index m and exponent n, such that D possesses a Baer ordering relative to the involution ∗. Using similar techniques we construct indecomposable division algebras with involution possessing a Baer

Reinhold Baer asked the relationship between certain properties in a nonempty set P with a partial operation (called an “add" by Baer [1]). The first paper in our sequence [Paper I] answered his question for a special type of an add called a pregroup by Stallings [12]. This paper [Paper II] answers an analogous question for a wider class of adds.

On the basis of the concept of grades of a fuzzy point to belongingness (∈) or quasi-coincident (q) or belongingness and quasi-coincident (∈ ∧q) or belongingness or quasi-coincident (∈ ∨q) in an intuitionistic fuzzy set of a ring, the notion of a (α,β )intuitionistic fuzzy subring and ideal is introduced by applying the Lukasiewicz 3-valued implication operator. Using the notion of fuzzy cut se...