Semi-arid ecosystems contribute about 40% to global net primary production (GPP) even though water is a major factor limiting carbon uptake. Evapotranspiration (ET) accounts for up to 95% of the water loss and in addition, vegetation can also mitigate drought effects by altering soil water distribution. Hence, partitioning of carbon and water fluxes between the soil and vegetation components is...

this paper represents a theoretical model from which the supply function for a durable goods is derived. it turns out that consumer at the equilibrium condition equates its user cost with the marginal value of services received by using an additional unit of durable goods. the stock price is obtained from this condition. in addition, at the equilbrium condition for producer, the stock price is ...

application of outflow water from treatment plants for irrigation as a non-usual water resource is being developed due to the lack of usual water resources in iran. activated carbon as a conditioner in water treatment procedures causes undesired changes in hydraulic properties of porous media and soil degradation. in this paper, the effects of activated carbon concentration on hydrodynamic prop...

User fees for municipal services may generate revenue for municipalities and their utility commissions, but they are equally important as prices for those services. Pricing services at marginal cost can lead to efficient production and consumption of the service, and efficient allocation of the service when capacity limits are reached; and it can help to guide investment on an efficient basis. ...

The upcoming stringent emission regulations and the depletion of oil resources have led to the development of alternate energy sources. In the present study the performance and emission characteristics of a singlecylinder directinjection diesel engine under neat diesel operation and blends of alternative fuels with pure diesel are examined. The hot outlet water from the engine was circulated in...

Background & Aims of the Study: Due to one-way flow of water in rivers Guilan, pollution trade theory and the system of Ratio-Trade (TRS) and Streeter - Phelps equation has been used. This system, with a view of the river self- purification and how the distribution and transport of pollutants, determined Ratio-Trade system (TRS) between the units and using this method offers optimal pat...

Ecological evidence suggests that heterotrophic diazotrophs fueled by organic carbon respiration in sediments play an important role in marine nitrogen fixation. However, fundamental knowledge about the identities, abundance, diversity, biogeography, and controlling environmental factors of nitrogen-fixing communities in open ocean sediments is still elusive. Surprisingly, little is known also ...

Based on a numerical model where climate change affects productivity, the second-best optimal carbon tax is found to exceed marginal social damage by 53 percent, and " marginal private damage " (aggregate households' marginal willingness to pay) by 73 percent. Annual welfare gains from carbon taxation are estimated at $3.58 billion when marginal damage is $40 per ton; employment also increases....