Most cosmological models for γ-ray bursts (GRBs) invoke the production of a “fireball” 1−3 in a compact region, as indicated by the short time variability of the observed GRBs. The high density of ee pairs in such fireballs inevitably makes them opaque to γ-rays and requires the γ-ray emission to take place only after the fireball has expanded and became optically thin to γ’s. Many of the “trad...

Allan Adams (MIT), Scott F. Anderson (Univ. of Washington), Andy Becker (U. Washington), Geoffrey C. Bower (UC Berkeley), Niel Brandt (Penn State), Bethany Cobb (UC Berkeley), Kem Cook (Lawrence Livermore National Laboratory/IGPP), Alessandra Corsi (INAF-Roma), Stefano Covino (INAF-Osservatorio Astronomico di Brera), Derek Fox (Penn State University), Andrew Fruchter (STSCI), Chris Fryer (Los A...

A conventional explanation of the dipole anisotropy of the cosmic microwave background (CMB) radiation is in terms of the Doppler effect: our galaxy is moving with respect to CMB frame with ∼ 600 km s. However, as the deep redshift surveys fail to reveal a convergence of the large scale flow to zero at distances as large as d ∼ H15, 000 km s (Lauer & Postman, 1994), the uniqueness of the conven...

safety of a dam depends upon not only design and construction but also on the monitoring at the early years after impoundment. shahr- chai dam is located on the shahr- chai river and 12 km away from urmia city in the south- west. the construction of dam was ended in winter 2004, and then both of the dam impoundment and monitoring instrument readings were started, immediately. after ending dam c...

Following Blumenthal et al. 1] and Piran et al. 2] I discuss a simple model for the gravitational formation of voids. This model enables us to estimate the primordial perturbation required on the scale of voids. A comparison of this condition with the constraints on the spectrum of uctuations derived from CMBR observations reveals that gravitational growth of large voids require more power on t...

Delineating positive psychological processes in inhabiting the body, as well as quantitative measures to assess them, can facilitate progress in the field of prevention of eating disorders by expanding outcome evaluation of prevention interventions, identifying novel mediators of change, and increasing highly needed research into protective factors. Moreover, enhancing positive ways of inhabiti...

The quality of life in cities is one the most attractive research cases for researchers and urban planners. Best-Worst Method (BWM) recent multi-criteria decision-making methods (MCDM). In this study, we have tried to rank districts 1, 2, 3 & 8 Tabriz city by using a combination BWM TOPSIS Geographic Information System (GIS) capabilities. Twenty criteria been considered study. At first, map was...