Introduction: The rapid use of computed tomography (CT) scan is of great concern, due to increase in patients’ dose. Optimization of CT protocol is a vital issue in dose reduction. This study aimed to optimize radiation dose in cranial CT and assess modifications in image quality under radiation dose reduction. Material and Methods: A poly(me...

background: radon is the second leading cause of lung cancer after smoking. in canada, the health authorities have no access to comprehensive profile of the communities built over uranium-rich micro-geological settings. the present indoor radon monitoring guideline is unable to provide an accurate identification of health hazards due to discounting several parameters of housing characteristics....

introduction the exposure of human beings to ionizing radiation from natural sources is a continuing and inescapable feature of life on earth. for most individuals, this exposure exceeds that from all man-made sources combined. materials and methods in this study, the annual effective dose in high level environmental background radiation areas (hlebras) of northern city of ramsar in iran was de...

Glioblastoma multiforme (GM) is the most common and most malignant astrocytoma in adults. After surgery, radiation therapy extends patient survival; however, in vivo response to radiation therapy is variable. The purpose of this investigation was to determine whether the cytogenetic abnormalities of GM differ according to patient response to radiation therapy. Radiation response was defined by ...

In many hydrological models, the amount of evapotranspired water is calculated using the potential evapotranspiration (PET) approach. The main driver of several PET approaches is net radiation, whose downward components are usually obtained from meteorological input data, whereas the upward components are calculated by the model itself. Thus, uncertainties can be large due to both the input dat...

Variable Line-Space gratings play an important role in focusing and aberration-reduced. They are widely used in spatial spectrum and synchrotron radiation facilities. However the design and fabrication methods of them are difficult. The problem is to be able to record holographically the expected grooves distribution. The geometric theory of aspheric wave-front recording optics is briefly descr...

[1] Seasonal coherence between satellite-derived phytoplankton parameters (chlorophyll a concentration (Chl) and phytoplankton bloom initiation time (BIT)), environmental variables (sea ice concentration, surface solar radiation, and wind speed), and climate patterns (El Niño 3.4, the Southern Annular Mode, the Pacific South America pattern, the semiannual oscillation, and the wave-3 stationary...

Solar surface irradiance is an important variable in many different fields, e.g., climate monitoring and solar energy. Remote sensing data are nowadays well established and the only observational data source in many regions of the world. Aerosols significantly affect the clear sky radiation and hence also the all sky radiation. In order to achieve the optimal accuracy for surface radiation, inf...

The effect of thermal radiation on the natural convection flow along a uniformly heated vertical porous plate with variable viscosity and uniform suction velocity was investigated numerically. The fluid considered in this study is of an optically dense viscous incompressible fluid of temperature-dependent viscosity. The laminar boundary layer equations governing the flow are shown to be nonsimi...

Linear polarization at the level of ∼ 1 − 3% has by now been measured in several GRB afterglows. Whereas the degree of polarization, P, was found to vary in some sources, the position angle, θp, was roughly constant in all cases. Until now, the polarization has been commonly attributed to synchrotron radiation from a jet with a tangled magnetic field that is viewed somewhat off axis. However, t...