This paper addresses a popular topic in science teaching and competitions for primary secondary school students. Experiments with colliding coins are relatively easy to perform therefore lessons. We used the idea competition we organized pupils aged 6 13 years. The is based on few experiments that participants have carry out before competition. Some years ago, 10- 11-year-old had experiment coi...

This paper studies the trade-off between two different kinds of pure exploration: breadth versus depth. We focus on the most biased coin problem, asking how many total coin flips are required to identify a “heavy” coin from an infinite bag containing both “heavy” coins with mean ✓ 1 2 (0, 1), and “light" coins with mean ✓ 0 2 (0, ✓ 1 ), where heavy coins are drawn from the bag with proportion ↵...

OBJECTIVES To determine the quantity and quality of bacterial and fungi on money coins and to identify those that could pose a public health risk. DESIGN Random sampling of coins from subjects within predetermined categories. SETTING Westlands division of Nairobi Metropolitan province. SUBJECTS Twenty-shilling coin samples were collected from matatu (a common commuter vehicle in Kenya) ta...

Compact e-cash schemes allow a user to withdraw a wallet containing k coins in a single operation, each of which the user can spend unlinkably. One big open problem for compact e-cash is to allow multiple denominations of coins to be spent efficiently without executing the spend protocol a number of times. In this paper, we give a (partial) solution to this open problem by introducing two addit...

Divisible E-cash systems allow users to withdraw a unique coin of value 2 from a bank, but then to spend it in several times to distinct merchants. In such a system, whereas users want anonymity of their transactions, the bank wants to prevent, or at least detect, double-spending, and trace the defrauders. While this primitive was introduced two decades ago, quite a few (really) anonymous const...

Foreign body ingestion is a common emergency problem in children. Coins are the most common foreign bodies lodged in the esophagus. This is a retrospective study where we reviewed 21 consecutive paediatric cases of coins impacted in the upper esophagus. These children were attended at the BP Koirala Institute of Health Sciences, Dharan, from March 2007 to March 2008. In this study, Mc-Intosh la...