in this paper we present the problem of designing a three level hub center network. in our network, the top level consists of a complete network where a direct link is between all central hubs.  the second and third levels consist of star networks that connect the hubs to central hubs and the demand nodes to hubs and thus to central hubs, respectively. we model this problem in an incomplete net...

The tumoricidal mechanisms of microbeam radiation therapy, and the more recently proposed minibeam radiation therapy, for the treatment of brain tumors are as yet unclear. Moreover, from among the various parameters of beam geometry the impact of changing the beam width is unknown. In this study, suppression of tumor growth in human glioma cells implanted in mice was evaluated experimentally us...

The area over which boundary information contributes to the determination of the center of an extended object was inferred from results of a bisection task. The object to be bisected was a rectangle with two long sinusoidally modulated sides, i.e. a wiggly rectangle. The spatial frequency and amplitude of the edge modulation were varied. Two object widths were tested. The modulation of the perc...

The International Gamma-Ray Astrophysics Laboratory (INTEGRAL) is dedicated to the fine spectroscopy (∆E: 2 keV FWHM @ 1.3 MeV) and fine imaging (angular resolution: 12 FWHM) of celestial gamma-ray sources in the energy range 15 keV to 10 MeV with concurrent source monitoring in the X-ray (3 35 keV) and optical (V, 550 nm) range. The mission is conceived as an observatory led by ESA with contri...

Abstract. We study quantum transport in honeycomb lattice ribbons with either armchair or zigzag edges. The ribbons are coupled to semi-infinite linear chains serving as the input and output leads and we use a tight-binding Hamiltonian with nearest-neighbor hops. For narrow ribbons we find transmission gaps for both types of edges. The center of the gap is at the middle of the band in ribbons w...

pulse echo b - scan imaging systems have been used for years in medical diagnosis. the theroy of such systems have been investigated by several researchers. in this paper, we introduce a new model for b - scan imaging system based on gaussian type transducer. an imaging system is normally identified by its point response function. this function describes the image of a single physical point obj...

objective(s): a novel iq-specttm method has become widely used in clinical studies. the present study compares the quality of myocardial perfusion images (mpi) acquired using the iq-specttm (iq-mode),conventional (180° apart: c-mode) and l-mode (90° apart: l-mode) systems. we assessed spatial resolution, image reproducibility and quantifiability using various physical phantoms. materials and me...

Abstract This study is conducted to investigate the effect of off-center placement twisted tape on flow distribution and heat transfer in a circular tube. The width 20, 18, 16, 14 12 mm performance discussed under same twist ratio 2.0. numerical analysis field, average Nusselt number, friction factor thermo-hydraulic parameter tube are with Reynolds number ranged from 2600 8760. results indicat...

to determine the relationship between yield and components of it and identify the effective traits on yield, 97 tomato landraces from west azarbaijan in iran (83 landraces) and iğdır in turkey (14 landraces) along with three commercial cultivars were studied using an alpha lattice design with two replications. the experiment was carried out at the agriculture and natural resources research cent...