Background Amomum compactum is one of the basic species of the traditional herbal medicine amomi fructus rotundus, with great pharmacology effect. The system position of A. compactum is not clear yet, and the introduction of this plant has been hindered by many plant diseases. However, the correlational molecular studies are relatively scarce. Methods The total chloroplast (cp) DNA was extrac...

We define a compactum X to be AB-compact if the cofinality of the character χ(x, Y ) is countable whenever x ∈ Y and Y ⊂ X. It is a natural open question if every AB-compactum is necessarily first countable. We strengthen several results from [Arhangel’skii and Buzyakova, Convergence in compacta and linear Lindelöfness, Comment. Math. Univ. Carolin. 39 (1998), no. 1, 159–166] by proving the fol...

Teleost fish skin is a multifunctional natural material with high penetration resistance owing to specialized puncture mechanisms of both the individual scale and the intact scaled integument. In this paper, we explore the possible additional role of the skin in fish undulatory locomotion by examining the structural and mechanical properties of the dermal stratum (s.) compactum layer of striped...

Let X be a compactum such that dimQ X ≤ n, n ≥ 2. We prove that there is a Q-acyclic resolution r : Z −→ X from a compactum Z of dim ≤ n. This allows us to give a complete description of all the cases when for a compactum X and an abelian group G such that dimGX ≤ n, n ≥ 2 there is a G-acyclic resolution r : Z −→ X from a compactum Z of dim ≤ n.

We prove that for every abelian group G and every compactum X with dimG X ≤ n ≥ 2 there is a G-acyclic resolution r : Z −→ X from a compactum Z with dimG Z ≤ n and dimZ ≤ n + 1 onto X.

We prove that for every compactum X and every integer n ≥ 2 there are a compactum Z of dim ≤ n + 1 and a surjective UV n−1-map r : Z −→ X such that for every abelian group G and every integer k ≥ 2 such that dimG X ≤ k ≤ n we have dimG Z ≤ k and r is G-acyclic.

The Noetherian type of a space is the least κ such that it has a base that is κ-like with respect to reverse inclusion. Just as all known homogeneous compacta have cellularity at most c, they satisfy similar upper bounds in terms of Noetherian type and related cardinal functions. We prove these and many other results about these cardinal functions. For example, every homogeneous dyadic compactu...

The aim of this study was to report the occurrence of Austrodiplostomum compactum metacercariae in the eyes of 98 specimens of loricariid fish (Hypostomus ancistroides, H. hermanni, H. iheringii, H. margaritifer, H. regani, H. strigaticeps, Hypostomus sp. and Megalancistrus parananus) from the Chavantes reservoir (23°07'36″S and 49°37'35″W) located in the rio Paranapanema, upper Paraná river ba...

Under GCH, k(X) _< ~(X) for every homogeneous compactum X. CH implies that a homogeneous compactum of countable ~r-weight is first countable. There is a compact space of countable 7r-weight and uncountable character which is homogeneous under MA+-~CH, but not under CH.

We continue to study one of the classic problems in general topology raised by P. S. Alexandrov: when a Hausdorff space X has continuous bijection (a condensation) onto compactum? concentrate on situation not only but also $$X\setminus Y$$ can be condensed compactum whenever cardinality Y does exceed certain $$\tau$$ .