Pacman Refutes the Coase Conjecture: Durable-Goods Monopoly with Discrete Demand

We analyze a dynamic game between consumers with unit demands and the sole seller of a durable good. Unlike previous analyses, we assume there exists a finite collection of buyers rather than a continuum. We show that none of the main conclusions of the durable-goods literature survives this change in assumption. In particular, for any demand curve there exists a subgame-perfect equilibrium such that for discount factors near one the monopolist's profit approaches the profit attainable under perfect price discrimination. This contradicts Coase's conjecture (1972)--proved formally for the continuum case by Gul, Sonnenschein, and Wilson (1986)--that the monopolist's profit must always converge to zero. It also implies that renting or precommitting to a path of prices-which Bulow (1982) and Stokey (1979) have shown, respectively, must always increase profit with a continuum of buyers--may strictly reduce profits when the collection of buyers is finite. Hence, while in other contexts the assumption of a continuum of consumers has proved an innocuous and useful simplification, in the context of durable-goods monopoly it has proved misleading.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100809/1/ECON026.pd

Intertemporal Self-Selection with Multiple Buyers Under Complete and Incomplete Information

We consider a monopolist selling durable goods to consumers with unit demands but different preferences for quality. The seller can offer items of different quality at the same time to induce buyers to self-select, as in Mussa-Rosen (1978), but is not artifically constrained to offer only one such menu. Instead the seller can offer without precommitment a sequence of menus over time. In the two-buyer case where the seller has complete information about each buyer's marginal valuation for quality, the seller's profits exceed what can be obtained from a single menu and sometimes approximate the profits of a perfectly discriminating monopolist. This result is not mere artifact of the assumption of complete information. As we show, even if the seller has incomplete information about the realized distribution of buyer types, he still may obtain higher expected profits (smetimes the entire surplus) by making a sequence of offers rather than a single offer.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100831/1/ECON028.pd

Price Discrimination and Intertemporal Self-Selection

We consider a monopolist selling durable goods to consumers with unit demands but different preferences for quality. The seller can offer items of different quality at the same time to induce buyers to self-select, as in Mussa-Rosen (1978), but is not artifically constrained to offer only one such menu. Instead the seller can offer a sequence of menus over time. In the two-buyer case, the seller finds it optimal to abandon multi-item menus with their quality distortions and instead induces self-selection intertemporally. In the unique subgame-perfect equilibrium of the finite-horizon game and the particular equilibrium that we consider in the infinite-horizon game, the monopolist offers in succession single items of efficient quality. In the continuous-time limit of the infinite-horizon game (under both complete and incomplete information), the monopolist approximates the present value of perfect price discrimination. All of our qualitative results for the two-buyer case continue to hold with an arbitrary, finite number of buyers of different types in some equilibria of the complete-information, infinite-horizon game.Center for Research on Economic and Social Theory, Department of Economics, University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/100820/1/ECON027.pd

On the lease rate, convenience yield and speculative effects in the gold futures market

By examining data on the gold forward offered rate (GOFO) and lease rates over the period 1996- 2009, we conclude that the convenience yield of gold is better approximated by the lease rate than the interest-adjusted spread of Fama & French (1983). Using the latter quantity, we study the relationship between gold leasing and the level of COMEX discretionary inventory and exhibit that lease rates are negatively related to inventories. We also show that Futures prices have increasingly exceeded forward prices over the period, and this effect increases with the speculative pressure and the maturity of the contracts

Influence of antigen distribution on the mediation of immunological glomerular injury

Influence of antigen distribution on the mediation of immunological glomerular injury. To determine if the site of immune reaction could influence the mediation and morphological expression of glomerular injury in experimental anti-glomerular basement membrane (anti-GBM) nephritis and membranous nephropathy, we studied the events that followed the in situ reaction of rat antibody with antigen planted in either the GBM (especially the lamina rara interna) or in the subepithelial space (SE). Non-nephritogenic amounts of noncomplement-fixing sheep anti-GBM or anti-tubular brushborder antibody were injected into separate groups of rats to plant sheep IgG in the GBM and SE, respectively. Kidneys containing sheep IgG were then transplanted into naive recipients that were passively immunized with rat anti-sheep IgG. There was marked proteinuria after 2 days (antigen in GBM: 226 ± 50.7; antigen in SE: 69 ± 50.7 mg/24 hr) that was abrogated by prior depletion of complement in both groups (antigen in GBM: 10.2 ± 1.7; antigen in SE: 14.3 ± 8.7 mg/24 hr). When antigen was planted in SE, inflammatory-cell depletion with either anti-neutrophil (PMN) serum or lethal irradiation had no effect on proteinuria. In contrast, anti-PMN abolished proteinuria (12.0 ± 5.6 mg/24 hr) and irradiation reduced it by 60% when antigen was in GBM. Glomeruli of kidneys with antigen in GBM were significantly larger and more hypercellular than those with antigen in SE after transplantation into immunized recipients. Endothelial cell injury and adherence of inflammatory cells to denuded GBM were prominent in the former (antigen in GBM), while glomeruli with antigen in SE showed only subepithelial deposits, adjacent slit-diaphragm displacement, and epithelial cell foot-process effacement. Thus, the reaction of antigen and antibody in glomeruli produced complement-mediated injury which was cell-independent when complex formation occurred on the outer aspect of the GBM but was cell-dependent when the same reagents reacted more proximally to the circulation. We therefore conclude that antigen distribution can critically influence the mediation and morphologic expression of immune glomerular injury and may, in part, account for variations in the clinical and histological manifestations of antibody-induced glomerular disease in humans.Influence de la distribution antigénique sur la médiation des lésions glomérulaires immunologiques. Afin de déterminer si le site de la réaction immune pourrait influencer la médiation et l'expression morphologique des lésions glomérulaires lors d'une néphrite expérimentale anti-membrane basale glomérulaire (anti-GBM) et d'une néphropathie extra-membraneuse, nous avons étudié les événements qui suivaient la réaction in situ d'anticorps de rat avec un antigène fixé soit dans la GBM (surtout dans la lamina rara interna), soit dans l'espace sous-épithélial (SE). Des quantités non nephritogènes d'anticorps anti-GBM, ou anti-bordure en brosse tubulaire de mouton ne fixant pas le complément ont été injectées à différents groupes de rats pour fixer de l'IgG de mouton dans la GBM et le SE, respectivement. Les reins contenant l'IgG de mouton étaient alors transplantés à des receveurs vierges passivement immunisés avec de l'IgG de rat antimouton. Il existait une protéinurie marquée après deux jours (antigène dans la GBM: 226 ± 50,7; antigène dans SE: 69 ± 50,7 mg/24 hrs) qui à été abrogé par une déplétion du complement dans les deux groupes (antigène dans la GBM: 10,2 ± 1,7; antigène dans SE: 14,3 ± 8,7 mg/24 hr). Lorsque l'antigène était fixé dans SE, une déplétion en cellules inflammatoires par du sérum anti-neutrophile (PMN) ou une irradiation léthale n'avaient pas d'effet sur la protéinurie. A l'opposé, anti-PMN supprimait la protéinurie (12,0 ± 5,6 mg/24 hr) et l'irradiation la réduisait de 60% lorsque l'antigène était dans la GBM. Les glomérules de reins ayant l'antigène dans la GBM étaient significativement plus gros et plus hyper-cellulaires que ceux ayant l'antigène dans SE après transplantation chez des receveurs immunisés. Les lésions cellulaires endothéliales et l'adhérence des cellules inflammatoires à des GBM nues étaient prédominantes chez les premiers (antigène dans la GBM) alors que les glomérules ayant l'antigène dans SE présentaient uniquement des dépôts sous-épithéliaux, un déplacement du slit-diaphragme adjacent et un effacement des pédicelles des cellules épithéliales. Ainsi, la réaction d'un antigène et d'un anticorps dans des glomérules a produit des lésions à médiation complémentaire indépentantes des cellules lorsque la formation de complexes survenait dans la partie extérieure de la GBM, mais dépendantes des cellules lorsque les mêmes réactifs interagissaient de façon plus proximale dans la circulation. Nous concluons donc que la distribution antigénique peut influencer de manière critique la médiation et l'expression morphologique des lésions glomérulaires immunes et qu'elle peut, en partie, rendre compte de variations dans les manifestations cliniques et histologiques de glomérulopathies à médiation par anticorps chez l'homme

How do women at increased, but unexplained, familial risk of breast cancer perceive and manage their risk? A qualitative interview study

<p>Abstract</p> <p>Background</p> <p>The perception of breast cancer risk held by women who have not had breast cancer, and who are at increased, but unexplained, familial risk of breast cancer is poorly described. This study aims to describe risk perception and how it is related to screening behaviour for these women.</p> <p>Methods</p> <p>Participants were recruited from a population-based sample (the Australian Breast Cancer Family Study - ABCFS). The ABCFS includes women diagnosed with breast cancer and their relatives. For this study, women without breast cancer with at least one first- or second-degree relative diagnosed with breast cancer before age 50 were eligible unless a <it>BRCA1 </it>or <it>BRCA2 </it>mutation had been identified in their family. Data collection consisted of an audio recorded, semi-structured interview on the topic of breast cancer risk and screening decision-making. Data was analysed thematically.</p> <p>Results</p> <p>A total of 24 interviews were conducted, and saturation of the main themes was achieved. Women were classified into one of five groups: don't worry about cancer risk, but do screening; concerned about cancer risk, so do something; concerned about cancer risk, so why don't I do anything?; cancer inevitable; cancer unlikely.</p> <p>Conclusions</p> <p>The language and framework women use to describe their risk of breast cancer must be the starting point in attempts to enhance women's understanding of risk and their prevention behaviour.</p

Collusion through Joint R&D: An Empirical Assessment

This paper tests whether upstream R&D cooperation leads to downstream collusion. We consider an oligopolistic setting where firms enter in research joint ventures (RJVs) to lower production costs or coordinate on collusion in the product market. We show that a sufficient condition for identifying collusive behavior is a decline in the market share of RJV-participating firms, which is also necessary and sufficient for a decrease in consumer welfare. Using information from the US National Cooperation Research Act, we estimate a market share equation correcting for the endogeneity of RJV participation and R&D expenditures. We find robust evidence that large networks between direct competitors – created through firms being members in several RJVs at the same time – are conducive to collusive outcomes in the product market which reduce consumer welfare. By contrast, RJVs among non-competitors are efficiency enhancing