The nitrogen cycle represents one of the most important nutrient cycles found in terrestrial ecosystems. Biological nitrogen removal is widely utilised for elimination of nitrogen from wastewater by means of nitrification and denitrification. Nitrogen removal can also be achieved through...

"We examine a model in which an upstream firm can sell directly online and through heterogeneous intermediaries to heterogeneous consumers engaging in time-consuming search. Direct online sales may be more or less convenient and involve costly returns if the good fits consumers poorly. Direct...

In a neoclassical growth model with public consumption, we show the following Pareto optimal tax rules. The government should tax leisure and private consumption at the same rate, and subsidize net investment at the same rate it taxes net capital income. Also, it should tax capital income more...

In a neoclassical growth model with public consumption, we show the following Pareto optimal tax rules. The government should tax leisure and private consumption at the same rate, and subsidize net investment at the same rate it taxes net capital income. Also, it should tax capital income more...

This paper studies optimal pay-as-you-go social security with positive bequests and endogenous fertility. With an investment externality, a competitive solution without social security su?ers from under-investment in capital and over-reproduction of population. We show that social security can...

In this paper we explore the implication of a morbidity risk for the relationship between longevity and annuitization. We divide old-age life into two periods with uncertain survival from the end of the first to the end of the second. We show that a rise in the survival rate causes different...

This paper examines the impact of demographic factors on saving, investment, and external balances. We derive a number of semi-structural equations from national accounting principle and the principle that external balances for the world as a whole must sum to zero. The resulting equations...

This paper examines how inflation taxation affects resource allocation and welfare in a neoclassical growth model with leisure, a production externality and money in the utility function. Switching from consumption taxation to inflation taxation to finance government spending reduces real money...