We consider a competitive version of the traditional aggregate production planning model with capacity constraints. In the general case, multiple products are produced by a few competing producers (oligopoly) with limited capacities. Production quantities, prices and consequently profits depend on production and allocation decisions of each producer. In addition, there is competition for the ra...

In view of the worldwide economic and environmental issues associated with the extensive use of petro-chemicals, there has been increasing research interest during the past decade in the value of residual biomass. Because of its renewable nature and abundant availability, residual biomass has attracted considerable attention as an alternate feedstock and potential energy source. To expand the r...

Impacts of toxic substances from oil production in the Alberta oil sands (AOS), such as polycyclic aromatic hydrocarbons (PAHs), have been widely debated. Studies have been largely restricted to exposures from surface mining in aquatic species. We measured PAHs in Woodland caribou (Rangifer tarandus caribou), moose (Alces americanus), and Grey wolf (Canis lupus) across three areas that varied i...

This paper presents a brief review on the current status of biodiesel production and its performance and emission characteristics as compression ignition engine fuel. This study is based on the reports on biodiesel fuel published in the current literature by different researchers. Biodiesel can be produced from crude vegetable oil, non-edible oil, waste frying oil, animal tallow and also from a...

Meningiomas as extra axial tumours, developing from arachnoid cap cells may occur from all dural structures, cranial and spinal and rarely outside of these structures (Whittle et al. 2004). The skull base is an area with multiple neural structures as well as brain supplying adjacent arteries and veins. Meningiomas, growing on or within the skull can thus be very challenging for the neurosurgeon...

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Helictites--an enigmatic type of mineral structure occurring in some caves--differ from classical speleothems as they develop with orientations that defy gravity. While theories for helictite formation have been forwarded, their genesis remains equivocal. Here, we show that a remarkable suite of helictites occurring in Asperge Cave (France) are formed by biologically-mediated processes, rather ...

Aneurysms arising from the petrous part of the internal carotid artery (ICA) are exceedingly uncommon. Only 21 angiographically proven cases have appeared in the literature [1-6) . The CT appearance of these rare lesions has not previously been reported. In the two cases described here, the CT pattern closely resembles that of the more common petrous apex meningioma. Consideration of a petrous ...

Carle M. Pieters*, Joseph Boardman, Bonnie Buratti, Alok Chatterjee, Roger Clark, Tom Glavich, Robert Green, James Head III, Peter Isaacson, Erick Malaret, Thomas McCord, John Mustard, Noah Petro, Cassandra Runyon, Matthew Staid, Jessica Sunshine, Lawrence Taylor, Stefanie Tompkins, Padma Varanasi and Mary White Department of Geological Sciences, Brown University, Providence, RI 02912, USA Anal...

Extraction and transportation of mineral resources today presents an increasing social problem, leading to environmental damage and the violation of human rights. In addition to economic and social controversies as well as political problems (such as corruption amongst state and local authorities), it caused population displacement on a large scale. The social costs of oil production illustrate...