Market Sharing Agreements and Collusive Networks

This paper analyzes the formation of market sharing agreements among firms in oligopolistic markets and procurement auctions. The set of market sharing agreements defines a collusive network, and the paper provides a complete characterization of stable and efficient collusive networks when firms and markets are symmetric. Efficient networks are regular networks, where firms have the same number of market sharing agreements. Stable networks are formed of complete alliances, of different sizes, larger than a minimal threshold. Typically, stable networks display fewer market sharing agreements than the optimal network for the industry and more market sharing agreements than the socially optimal network. When firms or markets are asymmetric, incomplete alliances can form in stable networks, and stable networks may be underconnected with respect to the social optimum.Market sharing, Collusion, Economic networks, Oligopoly, Auctions

Optimal Ownership Structures in Asymmetric Joint Ventures

This paper investigates the relation between asymmetries in the distribution of shares in joint ventures and asymmetries between the parent companies. When the joint venture and the parent companies are controlled by separate entities, we provide a simple formula to compute the optimal ownership structure. This formula is applied to various models of market interaction, showing that larger companies should have a larger fraction of shares, and so should companies whose goods are closer substitutes of the product of the joint venture, or companies who have a higher cost of transformation of the input produced by a joint venture.Joint ventures, Strategic alliances, Ownership structure, Asymmetries

Australian coal mining: Estimating technical change and resource rents in a translog cost function

This paper estimates a translog cost function for the Australian coal industry from 1968/69 to 2004/05. We use a variable measuring the shift to open-pit mining to capture the impact of embodied technical change, while using a time trend to capture the impact of other technical change and changing resource rents. The cost function is estimated with Zellner's SUR procedure. The shift to open-cut mining is shown to be important in lowering cost during the 1970s and 1980s, but more recently cost reduction is captured by the time trend

Working on the railroad: coastal streams prioritization to inform restoration planning

Puget Sound’s nearshore has been substantially modified since the Industrial Revolution with extensive infrastructure developed along the shoreline. In Washington State, the BNSF railroad right-of-way runs along 52 miles of the shoreline, while another 73 miles of railroad is within 200 feet of the shoreline. In many places, the railroad forms a barrier between the coastal watershed and the shoreline preventing the delivery of water, sediment, wood and organic matter into the nearshore. This creates ongoing degradation of habitat quality in the nearshore, including small estuaries and coastal embayments, which provide important habitat to juvenile Chinook salmon. In addition, the modifications associated with the railroad also limit juvenile salmon movements in estuaries, including juvenile chinook who are documented using the estuaries and freshwater habitats of non-natal streams. Nearshore restoration along the railroad is expensive and requires extensive planning. To maximize environmental benefits, restoration efforts should be focused on those areas that provide substantial benefits to fish habitat and nearshore processes. Confluence Environmental is leading a project to prioritize and evaluate coastal embayments and streams along the 125 miles of railroad-impacted shoreline. The project is synthesizing existing data, as well as identifying and filling data gaps for use in the prioritization. This prioritization will be integrated with a list of known railroad maintenance and upgrade needs. An advisory team is guiding the development of the prioritization to ensure it can support identified local and regional restoration outcomes. The outcome of the project will include a prioritized list of coastal embayments and streams to support strategic restoration choices and potential matching of upgrades and maintenance along the railroad to mitigation projects that will benefit fisheries and shoreline processes. The list will also enable independent funders to evaluate the benefits among restoration projects

The significance of guinea worm infection in the immunological diagnosis of onchocerciasis and bancroftian filariasis

Infections with Dracunculus medinensis frequently occur in the same geographical area as infections with Onchocerca volvulus and Wuchereria bancrofti. This study analysed the significance of D. medinensis infections for the specificity and sensitivity of available tests for antibody-based diagnosis of onchocerciasis (using individual recombinant clones OV-10, OV-11 and OV-16, and the OV-7/OV-10/OV-16 tri-cocktail, in an enzyme-linked immunosorbent assay) and for circulating antigen-based diagnosis of bancroftian filariasis (using the TroBio™ and the ICT™ card tests). Some immunological cross-reactivity was observed with all tests. When using individual recombinant O. volvulus antigens, the highest assay indices were obtained for clone OV-10, and the lowest for clone OV-16. Testing the serum responses against the tri-cocktail of recombinant antigens did not notably improve the assay indices. Two of 40 serum samples from individuals with patent dracunculiasis gave a false positive response in the ICT™ test and one of these was also positive in the TropBio™ test. Possible implications of applying these diagnostic assays in areas endemic for dracunculiasis are discusse

Childhood Obesity, Cortical Structure, and Executive Function in Healthy Children.

The development of executive function is linked to maturation of prefrontal cortex (PFC) in childhood. Childhood obesity has been associated with changes in brain structure, particularly in PFC, as well as deficits in executive functions. We aimed to determine whether differences in cortical structure mediate the relationship between executive function and childhood obesity. We analyzed MR-derived measures of cortical thickness for 2700 children between the ages of 9 and 11 years, recruited as part of the NIH Adolescent Brain and Cognitive Development (ABCD) study. We related our findings to measures of executive function and body mass index (BMI). In our analysis, increased BMI was associated with significantly reduced mean cortical thickness, as well as specific bilateral reduced cortical thickness in prefrontal cortical regions. This relationship remained after accounting for age, sex, race, parental education, household income, birth-weight, and in-scanner motion. Increased BMI was also associated with lower executive function. Reduced thickness in the rostral medial and superior frontal cortex, the inferior frontal gyrus, and the lateral orbitofrontal cortex partially accounted for reductions in executive function. These results suggest that childhood obesity is associated with compromised executive function. This relationship may be partly explained by BMI-associated reduced cortical thickness in the PFC.Wellcome Trust Bernard Wolfe Health Neuroscience Fun