In this letter we explore the suggestion of Quashnock and Lamb (1993) that nearest neighbor correlations among gamma ray burst positions indicate the possibility of burst repetitions within various burst sub-classes. With the aid of Monte Carlo calculations we compare the observed nearest neighbor distributions with those expected from an isotropic source population weighted by the published BA...

Collisions of particles in black hole ergospheres may result in an arbitrarily large center-of-mass energy. This led recently to the suggestion [M. Bañados, J. Silk, and S. M. West, Phys. Rev. Lett. 103, 111102 (2009)] that black holes can act as ultimate particle accelerators. If the energy of an outgoing particle is larger than the total energy of the infalling particles, the energy excess mu...

Depending upon the various models and assumptions, the existing literature on Gamma Ray Bursts (GRBs) mentions that the gross theoretical value of the duration of the burst in the hydrodynamical models is τ ∼ rγ/2ηc, where rγ is the radius at which the blastwave associated with the fireball (FB) becomes radiative and sufficiently strong. Here η ≡ E/Mc, c is the speed of light, E is initial lab ...

Sari & Piran 1997a have demonstrated that the time structure of gamma-ray bursts must reflect the time structure of their energy release. A model which satisfies this condition uses the electrodynamic emission of energy by the magnetized rotating ring of dense matter left by neutron star coalescence; GRB are essentially fast, high field, differentially rotating pulsars. The energy densities are...

background: cutaneous leishmaniasis constitutes a major public health problem in many parts of the world including iran. the primary objective of this study was to identify leishmania spe­cies in endemic districts of kerman province, south-eastern iran . methods: this study was conducted by random sampling as cross- sectional descriptive between 2008 and 2010. overall, 203 skin scraping smears ...

objective: the aim of this study is to provide a management plan for the sykan watershed of darre shahr city located in ilam province using gis in land use planning. methods: for land using of sykan watershed of ilam province with about 9 hectares area, map of classes, elevation, percent slope, geographical aspects, soil characteristics, vegetation density and the final map units were combined ...

depth of frost penetration is one of the main indices in agriculture, civil and transportation engineering. soil temperature is a function of several factors including: topography, solar radiation, air temperature, moisture content and other physical properties of soil such as thermal capacity, coefficient of heat conductivity, and specific heat. the main objective of the present paper is to de...

The spread of sewage in a coastal sea is a complex phenomenon that includes mechanisms that act on different environmental scales. In this work, a review of different mechanisms will be presented, all mostly confined to the hydrodynamic conditions of sewage that leaves a treatment plant and travels to the sea through sewage pipes (first stage), spreads into the sea through the diffuser orifices...