Klimb, J., On the minimal covering of infinite sets, Discrete Applied Mathematics 45 (1993) 161-168. Minimal covering of infinite sets is studied. It is shown that if BC2’ is closed, then /* contains a minimal covering of X. If r// is a covering of X, then fl is closed on X if and only if there is an admissible functionf: X-1 4 which has no chain. For star type set systems Theorem 15 gives a su...

We give a construction of nonsmooth self-dual projective algebraic varieties. They appear as certain projectivized orbit closures for some linear actions of reductive algebraic groups. Applying this construction to adjoint representations, we obtain geometric characterization of distinguished nilpotent elements of semisimple Lie algebras [BC1], [BC2] (i.e., nilpotent elements whose centralizer ...

Iron chalcogenides, binary FeSe, FeTe and ternary FeTe x Se1-x , FeTe x S1-x and FeTe:O x , are the simplest compounds amongst the recently discovered iron-based superconductors. Thin films of iron chalcogenides present many attractive features that are covered in this review, such as: (i) easy fabrication and epitaxial growth on common single-crystal substrates; (ii) strong enhancement of supe...

Wild species are valued as a unique source of genetic variation, but they have rarely been used for the genetic improvement of quantitative traits. To identify trait-improving quantitative trait loci (QTL) alleles from exotic species, an accession of Oryza rufipogon, a relative of cultivated rice, was chosen on the basis of a genetic diversity study. An interspecific BC2 testcross population (V...

Genotypes of burley (cultivars B-21 and B-49), flue-cured (line VA-81 and cultivar PD-4), and Connecticut broadleaf (cultivar C9) tobacco (Nicotiana tabacum) resistant (R) or susceptible (S) to the tobacco cyst nematode Globodera tabacum tabacum were crossed. F1 progeny of burley and susceptible broadleaf were selfed and backcrossed to produce additional progeny for evaluation of resistance in ...

Maize (Zea mays) tassels underwent profound morphological changes during maize domestication and improvement. Although a number of genes affecting maize inflorescence development have been identified, the genetic basis of the morphological changes in maize tassels since domestication is not well understood. Here, using a large population of 866 maize-teosinte BC2 S3 recombinant inbred lines gen...

We present electronic transport and magnetic properties of single crystals of semimetallic half-Heusler phase LuPdBi, having theoretically predicted band inversion requisite for nontrivial topological properties. The compound exhibits superconductivity below a critical temperature Tc = 1.8 K, with a zero-temperature upper critical field Bc2 ≈ 2.3 T. Although superconducting state is clearly ref...

Wheat (Triticum aestivum L.) is known to be the world-leading cereal grain and the most important food in the world of agriculture.  Wheat offers a great wealth of material for genetic studies due to its wide ecological distribution and host of variation for various morphological and physiological characters.  To evaluate the genetic control of physical traits of grain in two crosses of winter ...