For every 1 ≤ i ≤ n, let Ti be a rooted star with root vi, where vi is not necessary to be its center. Then the union F = T1 ∪T2 ∪ . . .∪ Tn is called a rooted star forest with roots v1, v2, . . . , vn. Let P be a set of |F | points in the plane in general position containing n specified points p1, p2, . . . , pn, where |F | denotes the order of F . Then we show that there exists a bijection φ ...

We present the results of an XMM-Newton observation of the young (∼ 2 − 4 Myr) cluster around the hot star σ Orionis. In a previous paper we presented the analysis of the RGS spectrum of the central hot star; here we discuss the results of the analysis of the full EPIC field. We have detected 175 X-ray sources, 88 of which have been identified with cluster members, including very low-mass stars...

ABSTRACT We use Gemini GMOS-IFU observations of three luminous nearby Seyfert galaxies (Mrk 79, Mrk 348, and 607) to estimate the electron temperature (Te) fluctuations in inner 0.4–1.1 kpc region these galaxies. Based on Te determinations through [O iii]λ5007/λ4363 emission line ratio each spaxel, variations are quantified by computing integrated value fluctuation parameter (t2) projected plan...

In this paper our focus is to study certain covering properties in topological spaces by using semi-open covers. A part of this article deals with Rothberger-type covering properties. The notions of s-Rothberger, almost s-Rothberger, star s-Rothberger, almost star s-Rothberger, strongly star s-Rothberger spaces are defined and corresponding properties are investigated.

Let $D$ be an integral domain and $star$ a semistar operation stable and of finite type on it. We define the semistar dimension (inequality) formula and discover their relations with $star$-universally catenarian domains and $star$-stably strong S-domains. As an application, we give new characterizations of $star$-quasi-Pr"{u}fer domains and UM$t$ domains in terms of dimension inequal...

background: anti-angiogenic therapy is a crucial step in cancer treatment. the discovery of new anti-angiogenic compounds from marine organisms has become an attractive concept in anti-cancer therapy. because little data correlated to the pro- and anti-angiogenic efficacies of ophiuroidea, which include brittle star, the current study was designed to explore the anti-angiogenic potential of bri...