The open pit mine block sequencing problem (OPBS) seeks a discrete-time production schedule that maximizes the net present value of the orebody extracted from an open-pit mine. This integer program (IP) discretizes the mine’s volume into blocks, imposes precedence constraints between blocks, and limits resource consumption in each time period. We develop a “sliding time window heuristic” to sol...

Previous studies of the hydrodynamics of plant stems have shown that resistance to flow through bordered pits on the side walls of tracheids makes up a significant proportion of their total resistance, and that this proportion increases with tracheid diameter. This suggests a possible reason why tracheids with a diameter above around 100 microm have failed to evolve. This possibility has been i...

the determination of the ultimate pit limit (upl) is the first step in the open pit mine planning process. in this stage that parts of the mineral deposit that are economic to mine are determined. there are several mathematical, heuristic and meta-heuristic algorithms to determine upl. the optimization criterion in these algorithms is maximization of the total profit whilst satisfying the...

background: sacral pit is a shallow or deep dimple in the lower sacral region, with a reported prevalence of 3-5% among newborns. the aim of the present study was to investigate spinal cord abnormalities in newborns with sacral pit via ultrasound examinations. methods: in this descriptive study, 3071 infants born at 34-42 weeks of gestation were studied in hospitals affiliated to islamic azad u...

Poker is a game of imperfect information where players make inferences and investments under uncertainty. Winning requires skill as well as luck, and people play with different styles. Here I examine the roles of style and skill in a simplified poker game. I propose that style arises from mental limits in estimating odds and stakes, and I define style as a strategy for making decisions in light...

OBJECTIVE Elevated serum phosphate has emerged as a major risk factor for vascular calcification. The sodium-dependent phosphate cotransporter, PiT-1, was previously shown to be required for phosphate-induced osteogenic differentiation and calcification of cultured human vascular smooth muscle cells (VSMCs), but its importance in vascular calcification in vivo and the potential role of its homo...

Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but they likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height because of path-length resistance and gravit...

In the open-pit mining, one of the first decisions that must be made in production planning stage, after completing the design of final pit limits, is determining of the processing plant cut-off grade. Since this grade has an essential effect on operations, choosing the optimum cut-off grade is of considerable importance. Different goals may be used for determining optimum cut-off grade. One of...