This paper formulates a mathematical model for the Green Vehicle Routing Problem (GVRP), incorporating bi-fuel (natural gas and gasoline) pickup trucks in a mixed vehicle fleet. The objective is to minimize overall costs relating to service (earliness and tardiness), transportation (fixed, variable and fuel), and carbon emissions. To reflect a real-world situation, the study considers: (1) a co...

We analyze the sequential choices of locations in the Hotelling [0, 1] space of variety-differentiated products. n firms locate in sequence, one at a time. In stage n+1, all firms choose prices simultaneously. Firms anticipate correctly the decisions of subsequent entrants, as well as the equilibrium prices, so we analyze subgame-perfect equilibria. We analyze two games. In the first, the numbe...

the study is an analysis of processing methods, marketing channels, and profitability determinants of selected cassava products in kogi state, nigeria. the study was carried out in kogi east senatorial district of the state. a multi-stage sampling technique was employed in the selection of 120 respondents from whom information were collected and analyzed. the data used for the study were collec...

the purpose of this study was to evaluate the profitability of hatchery litter recycling into poultry feedstuff supplement. the data were collected in 2011 in 4 provinces, by direct interviewing of all hatcheries which used the hatchery litter drying machine. net present value (npv), benefit-cost ratio (bcr), and internal rate of return (irr) methods were applied for this analysis. in the studi...

We investigate the polyhedral structure of the lot-sizing problem with inventory bounds. We consider two models, one with linear cost on inventory, the other with linear and fixed costs on inventory. For both models, we identify facet-defining inequalities that make use of the inventory bounds explicitly and give exact separation algorithms. We also describe a linear programming formulation of ...

Wepresent an analytically tractable dynamic stochastic general equilibrium model that incorporates micro-level fixed and convex adjustment costs. We provide an explicit characterization of equilibrium dynamics by a system of nonlinear stochastic difference equations. We provide general conditions under which our model features investment lumpiness at the microeconomic level, but aggregate dynam...

This paper investigates the effect of economic integration on the ability of firms to maintain a collusive understanding about staying out of each other’s markets. The paper distinguishes among different types of trade costs: ad valorem, unit, fixed. It is shown that for a sufficient reduction of ad valorem trade costs, a cartel supported by collusion on either quantities or prices will be weak...

This paper studies the impact of trade costs reduction on geographical concentration in the presence of firm heterogeneity and overhead type of export fixed costs. Firm heterogeneity with the export fixed costs hampers full agglomeration through weakening the forward and backward linkages and fortifying the market crowding effect. Rather than catastrophic agglomeration that the standard new eco...

BACKGROUND There are few published estimates of the cost of pediatric antiretroviral therapy (ART) in Africa. Our objective was to estimate the outpatient cost of providing ART to children remaining in care at six public sector clinics in Zambia during the first three years after ART initiation, stratified by service delivery site and time on treatment. METHODS Data on resource utilization (d...