The control problem and Dynamic programming is a powerful tool in economics and management. We review the dynamic programming problem from its beginning up to its present stages. A problem which was involved in physics and mathematics in I 7” century led to a branch of mathematics called calculus of variation which was used in economic, and management at the end of the first quarter of the 20” ...

It is quite fitting for a symposium reviewing progress in infant nutrition in the 20th century to start with a review of infant mortality rates during that time period. Indeed, it has been a truism in public health that, within limits, the infant mortality rate of any community, large or small, reflected its general state of health better than any other single indicator. Although no longer vali...

T racheostomy is one of the oldest surgical procedures reported in ancient medicine books. It became widely used in the 19th century during the diphtheria epidemics in Europe, and then in the 20th century following a series of devastating poliomyelitis epidemics in the 1950s [1–3]. Around the turn of the 20th century, JACKSON [4] standardised the indications for tracheostomy, the technique itse...

Transcranial magnetic stimulation has become an important field for both research in neuroscience and for therapy since Barker in 1985 showed that it was possible to stimulate the human motor cortex with an electromagnet. Today for instance, transcranial magnetic stimulation can be used to measure nerve conduction velocities and to create virtual lesions in the brain. The latter option creates ...

The observed global warming of the past century occurred primarily in two distinct 20-year periods, from 1925 to 1944 and from 1978 to the present. Although the latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear because this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) fo...

Three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968. The latter 2 were in the era of modern virology and most thoroughly characterized. All 3 have been informally identified by their presumed sites of origin as Spanish, Asian, and Hong Kong influenza, respectively. They are now known to represent 3 different antigenic subtypes of influenza A v...

[1] The African Sahel experienced severe drying between the 1950s and the 1980s, with partial recovery since. We compare Sahel rainfall in the 20th century, pre-industrial, and increased greenhouse gases (GHG) simulations produced for the Intergovernmental Panel on Climate Change (IPCC). The simulations forced by 20th century concentrations of aerosol and GHG reproduce (i) a global change in SS...