Are there limits to human longevity? We suggest a new demographic model to describe human demographic trajectories. Specifically, the model mathematically defines the limits of longevity. Through the demographic analysis of trends for Sweden (between 1751 and 2002), Switzerland (between 1876 and 2002) and Japan (between 1950 and 1999), which are the longest-lived countries, we would like to dem...

The laws of physics imposes limits on increases in computing power. Two of these limits are interconnect wires in multicomputers and thermodynamic limits to energy dissipation in conventional irreversible technology. Quantum computing is a new computational technology that promises to eliminate problems of latency and wiring associated with parallel computers and the rapidly approaching ultimat...

in this study, a hybrid intelligent model has been designed to predict groundwater inflow to a mine pit during its advance. novel hybrid method coupling artificial neural network (ann) with genetic algorithm (ga) called ann-ga, was utilised. ratios of pit depth to aquifer thickness, pit bottom radius to its top radius, inverse of pit advance time and the hydraulic head (hh) in the observation w...

abandoned surface mine excavations can be a major environmental, social and/or human healthproblem for the mining industry as well as for the community living nearby. this problem is exacerbated by therapidly growing population encroaching on areas of historic mined lands. the aim of this studywas to assess thesafety status of the historic nyala mine excavation with the purpose of coming up wit...

Many proposed microfluidic biosensor designs are based on the measurement of the resonances of an optical microcavity. Fluorescence-based resonators tend to be simpler and more robust than setups that use evanescent coupling from tuneable laser to probe the cavity. In all sensor designs the detection limits depend on the wavelength resolution of the detection system, which is a limitation of fl...

BACKGROUND AND AIMS The lack of triangulation has restricted the growth of flexible endoscopic surgical techniques. In addition, endoscope channel size limits the type of tools that can be used. A novel percutaneous intragastric trocar (PIT) has been developed to address these issues. The aim of this study was to evaluate the procedural characteristics of PIT placement and removal, as well as i...