OBJECTIVE To examine the relation between coins ingested by children and the Dow Jones Industrial Average. DESIGN Observational study. Main outcome measures Total value of coins ingested and number of incidents of coins versus other objects swallowed, measured before and after the stock market crash of October 2008. RESULTS Eighteen objects, including 11 coins, were ingested (NASDAQ (numism...

It seems fitting that, at a seminar organized to celebrate the 100 th anniversary of the Numismatic Society of India, I present a paper that offers a solution to a problem even older than the Society. In 1905, E. J. Rapson had published a small group of five coins which he identified as „Coins with reverse type “Svastika.”‟ 2 The coins were unified by the presence on their reverses of a central...

In this study we report the underlying reasons to why bacteria are present on banknotes and coins. Despite the use of credit cards, mobile phone apps, near-field-communication systems, and cryptocurrencies such as bitcoins which are replacing the use of hard currencies, cash exchanges still make up a significant means of exchange for a wide range of purchases. The literature is awash with data ...

We consider the k-payment problem: given a total budget of N units, represent this budget as a set of coins, so that any k exact payment requests of total value at most N can be made using k disjoint subsets of the coins. The goal is to minimize the number of coins for any given N and k The actual payments are made on-line, namely without knowing all payment requests in advance. Our motivation ...

We consider the k-payment problem: given a total budget of N units, the problem is to represent this budget as a set of coins, so that any k exact payments of total value at most N can be made using k disjoint subsets of the coins. The goal is to minimize the number of coins for any givenN and k, while allowing the actual payments to be made on-line, namely without the need to know all payment ...

We consider combinatorial and computational issues that are related to the problem of moving coins from one configuration to another. Coins are defined as non-overlapping discs, and moves are defined as collision free translations, all in the Euclidean plane. We obtain combinatorial bounds on the number of moves that are necessary and/or sufficient to move coins from one configuration to anothe...