The p-principal points of a random variable X with finite second moment are those p points in R minimizing the expected squared distance from X to the closest point. Although the determination of principal points involves in general the resolution of a multiextremal optimization problem, existing procedures in the literature provide just a local optimum. In this paper we show that standard Glob...

*Corresponding author: Dr. Ali Reza Kamali Asl, Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran. Fax: +98 21 22431780 E-mail: [email protected] Background: A variable resolution X-ray (VRX) CT scanner provides a great increase in the spatial resolution. In VRX CT scanners, the spatial resolution of the system and its field of view (FOV) can be changed according to the...

Introduction: Mini Computed Tomography (mini-CT) was suggested in biomedical research to investigate tissues and small animals. We present designed and built a mini x-ray computed tomography (mini-CT) for small animals as well as industrial component imaging. Materials and Methods: The system used in this study includes a X-ray tube 20kV to 160kV and a flat pa...

A curved-crystal x-ray emission spectrometer has been designed and built to measure 2-5 keV x-ray fluorescence resulting from a core-level excitation of gas phase species. The spectrometer can rotate 180 degrees, allowing detection of emitted x rays with variable polarization angles, and is capable of collecting spectra over a wide energy range (20 eV wide with 0.5 eV resolution at the Cl K edg...

Three species of the genus Xylaria (Xylariaceae) are presented based on collections from Guilan Province, Iran. Both morphological and molecular characteristics were used in order to identify these species. Xylaria longissima sp. nov. is described and illustrated as a new Xylaria species and X. cf. striata and X. xylarioides are reported as new records from Iranian mycobiota. Xylaria longissima...

three species of the genus xylaria (xylariaceae) are presented based on collections from guilan province, iran. both morphological and molecular characteristics were used in order to identify these species. xylaria longissima sp. nov. is described and illustrated as a new xylaria species and x. cf. striata and x. xylarioides are reported as new records from iranian mycobiota. xylaria longissima...

Let K be a discretely valued field with ring of integers $$\mathcal {O}_K$$ perfect residue field. K(x) the rational function in one variable. $${\mathbb {P}}^1_{\mathcal {O}_K}$$ standard smooth model {P}}^1_K$$ coordinate x. $$f(x) \in \mathcal {O}_K[x]$$ squarefree polynomial corresponding divisor zeroes $${{\,\mathrm{div}\,}}_0(f)$$ on . We give an explicit description minimal embedded reso...