Concepts of spatial scale, such as extent, grain, resolution, range, footprint, support and cartographic ratio are not interchangeable. Because of the potential confusion among the definitions of these terms, we suggest that authors avoid the term ‘‘scale’’ and instead refer to specific concepts. In particular, we are careful to discriminate between observation scales, scales of ecological phen...

background: the main threats to human health from heavy metals are associated with exposure to plumb (pb), cadmium, mercury, and arsenic. some hazards that threat human health are the results of environmental factors and the relevant pollutions. some important categories of diseases including (cancers) have considerable differences in various places, as observed in their spatial prevalence and ...

one of the limitations of orthogonal frequency division multiplexing (ofdm) in many applications is its sensitivity to frequency shifts, errors normally referred to as carrier frequency offset (cfo). although, this small offset is negligible in conventional single carrier communication systems, it is a severe problem in the ofdm systems. because, the carriers in ofdm are inherently closely spac...