A Dual Characterization of Incentive Efficiency

We show that incentive e cient allocations in economies with adverse se- lection and moral hazard can be determined as optimal solutions to a linear programming problem and we use duality theory to obtain a complete charac- terization of the optima. Our dual analysis identi es welfare e ects associated with the incentives of the agents to truthfully reveal their private information. Because these welfare e ects may generate non-convexities, incentive e cient allocations may involve randomization. Other properties of incentive e cient allocations are also derived

Incentive compatibility and pricing under moral hazard

We study a simple insurance economy with moral hazard, in which random contracts overcome the non-convexities generated by the incentive-compatibility constraints. The novelty is that we use linear programming and duality theory to study the relation between incentive compatibility and pricing. Using linear programming has the advantage that we can impose the incentive-compatibility constraints on the agents that are uninformed (the insurance firms). In contrast, most of the general equilibrium literature imposes them on the informed agents (the consumers). We derive the two welfare theorems, establish the existence of a competitive equilibrium, and characterize the equilibrium prices and allocations. Our competitive equilibrium has two key properties: (i) the equilibrium prices reflect all the relevant information, including the welfare costs arising from the incentive-compatibility constraints; (ii) the equilibrium allocations are the same as when the incentive-compatibility constraints are imposed on the consumers

General Equilibrium with Asymmetric Information: A Dual Approach

We study markets where the characteristics or decisions of certain agents are relevant but not known to their trading partners. Assuming exclusive trans- actions, the environment is described as a continuum economy with indivis- ible commodities. We characterize incentive constrained eÆcient allocations as solutions to linear programming problems and appeal to duality theory to demonstrate the generic existence of external e ects in these markets. Because under certain conditions such e ects may generate non-convexities, random- ization emerges as a theoretic possibility. In characterizing market equilibria we show that, consistently with the personalized nature of transactions, prices are generally non-linear in the underlying consumption. On the other hand, external e ects may have critical implications for market eÆciency. With ad- verse selection, in fact, cross-subsidization across agents with di erent private information may be necessary for optimality, and so, the market need not even achieve an incentive constrained eÆcient allocation. In contrast, for the case of a single commodity, we nd that when informational asymmetries arise after the trading period (e.g. moral hazard; ex post hidden types) external e ects are fully internalized at a market equilibrium

Reinventing Female Fashion: From Victorian Apparel to Steampunk Expression of the Self

First impressions have always been said to be extremely important in most situations. Traditionally, outfit is linked to one’s conception of the society one lives in. Some scholars, such as Roberts, argue that fashion was used in Victorian times as a means of control. Crinolines, crinolinettes and tight-lacing were elements of repression deriving from the social consideration of women as objects that must observe certain rules of behaviour; as Ellis states, a woman was expected “to suffer and be still” (Roberts 556). However, the introduction of new materials and new designs has given rise to a reinterpretation of this Victorian apparel. This reinvented female fashion has become a distinguishing mark of the Steampunk Neo-Victorian sub-culture, which recovers nineteenth century female fashion and gives it a radically different meaning. My paper will focus on the transition from Victorian to Steampunk fashion and the new implications coming from the reinterpretation of the different elements used for female appearance. Different cultural productions of the twentieth and the twenty-first centuries will be used as examples of my main arguments, paying special attention to the character of Mina Harker as represented in Stoker’s masterpiece Dracula (1897) and in Norrington’s The League of Extraordinary Gentlemen (2003). As the members of this community are increasing not only in Britain, but worldwide, research on the different features of this movement become highly relevant for cultural studies. Fashion can be considered to be a good starting point for research on the topic of gender identities and new gender stereotypes within the steampunk trend. To provide my arguments with a relevant theoretical framework I will make reference to several works by experts in the field of gender and cultural studies. Foucaultian notions about control over female bodies will also be relevant in my paper, as well as Butlerian ideas about the construction of gender identity. Given that steampunk is set in a retro-futuristic world, some of Braidotti’s notions about the post-human will be also discussed. My main thesis is that steampunk female fashion has developed to a point in which it is not just a reinterpretation of the Victorian past, but something totally new that has enabled the twenty-first century woman to externalise her inner self and her true identity. For instance, Victorian tight-lacing has moved from being a means of patriarchal control to a way for women to show self-confidence and a control over their own bodies. Moreover, cross-dressing has also become part of this sub-culture, being highly frequent in steampunk conventions and meetings.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A Note on Walrasian Equilibria with Moral Hazard and Aggregate Uncertainty

In a fundamental contribution, Prescott and Townsend (1984) [PT] have shown that the existence and efficiency properties of Walrasian equilibria extend to economies with moral hazard, when agents' trades are observable (exclusive contracts can be implemented). More recently, Bennardo and Chiappori (2003) [BC] have argued that Walrasian equilibria may (robustly) fail to exist when the class of moral hazard economies considered by Prescott and Townsend is generalized to allow for the presence of aggregate, in addition to idiosyncratic, uncertainty and for preferences which are nonseparable in consumption and effort. We re-examine here the existence and efficiency properties of Walrasian equilibria in the moral hazard economy considered by Bennardo and Chiappori. We show that Walrasian equilibria always exist in such economy and are incentive efficient, so the results of Prescott and Townsend continue to hold in the more general set-up considered by Bennardo and Chiappori

The role of earthworms in nitrogen release from herbage residues : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Soil Science at Massey University

Decomposition and nutrient release from pasture litter were examined in two biotic systems; either with or without large organisms ("macrobes"). Earthworms were the test macrobe and nitrogen (N) the test nutrient. This experiment addressed the hypothesis that consumption of herbage residues by macrobes, as opposed to microbes, should result in more of the contained N becoming available for uptake by plants or for loss processes, because macrobes oxidise a greater proportion of the contained carbon (C) by energetics. Earthworms influenced both soil metabolism and mineral N availability, irrespective of litter type (ryegrass or clover) and temperature (15 or 22.5 C). Carbon dioxide evolution and oxygen consumption increased by 26% and 39%, respectively, in the presence of earthworms. After an 11-week incubation about 50% more mineral N was recorded in the soils containing earthworms. Moreover, less microbial biomass was recorded in the presence of worms. This influence of macrobes carried over into a subsequent, exhaustive cropping experiment, using ryegrass as the test plant. Where soils had been previously influenced by earthworms, there was a significant increase in plant growth and N uptake. Carbon dioxide evolved during incubation was highly correlated with soil mineral N (r= 0.84** ) present at the conclusion of incubation, and also with subsequent plant dry matter yield (r= 0.75** ) and plant N yield (r=0.85** ). The link between elaborated C and contained N has long been recognised as providing stability to organic residues in soils. In the design of this experiment, other influences of macrobes (e.g. mixing or structural influences) were largely obviated, so one can conclude that nitrogen availability was increased primarily through carbon respiration by the macrobial population. These results offer a fresh perspective on the balance between mineralisation and immobilisation in the soil-plant complex and, hence, on the dynamics of nutrients contained in organic matter. Better understanding of these relationships may allow improved management of the dynamics of soil organic matter in temperate grassland ecosystems

Inflation, Prices, and Information in Competitive Search

We study the effects of inflation in a competitive search model where each buyer’s utility is private information, and money is essential. The equilibrium is efficient at the Friedman rule, but inflation creates an inefficiency in the terms of trade. Buyers experience a preference shock after they are matched with a seller, and thus they have a precautionary motive for holding money. Sellers, who compete to attract buyers, post non-linear price schedules. As inflation rises, sellers post relatively flat price schedules, which reduce the need for precautionary balances. These price schedules induce buyers with a low desire to consume to purchase inefficiently high quantities because of the low marginal cost of purchasing goods. In contrast, buyers with a high desire to consume purchase inefficiently low quantities as they face binding liquidity constraints. The model fits historical US data on velocity and interest rates.Publicad