Investment is often irreversible: once installed, capital has little or no value unless used in production. This paper proposes, solves and characterizes a model of sequential irreversible investment by a firm facing uncertainty in technology, demand and price of capital. The solution can be found in closed form if simple (but not totally unrealistic) functional forms are assumed, and can be gi...

introduction : post endodontic pain is often linked to the inflammatory process as well as additional central mechanisms. the purpose of the present double-blind randomized clinical trial study was to compare the prophylactic effects of a derivative of zingiber officinale , zintoma , and ibuprofen on post endodontic pain of molars with irreversible pulpitis. materials and methods: the post endo...

Many drug delivery systems suffer from undesirable interactions with the host immune system. It has been experimentally established that covalent attachment (irreversible adsorption) of suitable macromolecules to the surface of the drug carrier can reduce such undesirable interactions. A fundamental understanding of the adsorption process is still lacking. In this paper, the classical random ir...

Carrier lifetime degradation of reactive ion etch-processed silicon samples are investigated. Two types of carrier recombination: reversible and irreversible degradations induced by reactive ion etching (RIE) are identified. Irreversible carrier recombination is due to surface damage created by the RIE process that propagates a few microns deep into the silicon substrate. Reversible carrier rec...