Contractually stable networks

We develop a theoretical framework that allows us to study which bilateral links and coalition structures are going to emerge at equilibrium. We define the notion of coalitional network to represent a network and a coalition structure, where the network speciÖes the nature of the relationship each individual has with his coalition members and with individuals outside his coalition. To predict the coalitional networks that are going to emerge at equilibrium we propose the concept of contractual stability which requires that any change made to the coalitional network needs the consent of both the deviating players and their original coalition partners. We show that there always exists a contractually stable coalitional network under the simple majority decision rule and the component-wise egalitarian or majoritarian allocation rules. Moreover, requiring the consent of group members may help to reconcile stability and e¢ ciency.Networks ; Coalition Structures ; Contractual Stability ; Allocation Rules Networks ; Strong efficiency

Social Rationalizability

Social environments constitute a framework in which it is possible to study how groups of agents interact in a society.The framework is general enough to analyse both non-cooperative and cooperative games.We identify a number of shortcomings of existing solution concepts that are used for social environments and propose a new concept called social rationalizability.The concept aims to identify the consequences of common knowledge of rationality and farsightedness within the framework of social environments.The set of socially rationalizable outcomes is shown to be non-empty for all social environments and it can be computed by an iterative reduction procedure.We introduce a definition of coalitional rationality for social environments and show that it is satisfied by social rationalizability.Social environments;rationalizability;coalitional rationality

Increasing Fiber and Protein Contents of Baked Products Using Local Produce

Consumers are increasingly opting for healthier food products, and two current trends are high fiber and high protein options. Using locally available produce or their manufacturing by-products may lower ingredient cost when making these products. Durian rind, which is generally thrown away, comprises 60% of a durian fruit and has about 27% crude fiber. Mung bean has about 23% protein and is relatively inexpensive. In this study, durian rind was cleaned, dried, ground, and added to muffins while mung beans were oven-roasted, ground, and added to crackers. Quality and acceptability of the products were evaluated. Among the ratios tested, the most preferred formulation for muffins had 10% durian rind powder, while that of crackers had 50% mung bean flour. Consumer acceptability of the products was tested using a 9-point hedonic scale. The control and fiber-fortified muffins had similar mean consumer acceptability scores of 8 (liked highly) for color, texture, taste, and overall acceptability. Crackers with mung bean flour had significantly higher mean scores than the control (7.5–8.0 vs. 6.8–7.4) for appearance, texture, flavor, and overall acceptability. The fiber-fortified muffin had 6.26% crude fiber while the mung bean crackers had 9.98% crude protein. The addition of durian rind powder and mung bean flour to baked products may adversely affect some quality parameters like texture, but there are ways to lessen these effects. The improvement in nutrition profile of the products shows the market potential of durian rind powder and mung bean flour

Social rationalizability

Social environments constitute a framework in which it is possible to study how groups of agents interact in a society.The framework is general enough to analyse both non-cooperative and cooperative games.We identify a number of shortcomings of existing solution concepts that are used for social environments and propose a new concept called social rationalizability.The concept aims to identify the consequences of common knowledge of rationality and farsightedness within the framework of social environments.The set of socially rationalizable outcomes is shown to be non-empty for all social environments and it can be computed by an iterative reduction procedure.We introduce a definition of coalitional rationality for social environments and show that it is satisfied by social rationalizability.

Fuzzy Play, Matching Devices and Coordination Failures

We revisit n-player coordination games with pareto-ranked nash equilibria. As a novelty, we introduce fuzzy play and a matching device. By fuzzy play we mean that each player does not choose which pure strategy to play, but instead chooses a nonempty subset of his strategy set that he submits to the matching device. The matching device is a very simple one. It randomly selects a match if possible, and it selects randomly some strategy belonging to the strategy set sent by each player otherwise. That is, it does not impose that the best alternatives are matched. Using the concepts of perfect nash equilibrium and of trembling-hand perfect rationalizability, we show that players coordinate directly on the pareto optimal outcome. This implies that they neither use the option of fuzzy play, nor make use of the matching device

Development of GCP ontology for sharing crop information.

Poster presented at 3rd international Biocuration Conference. Berlin (Germany). 17 Apr 2009

Communication networks, externalities and the price of information

Information goods (or information for short) play an essential role in modern economies. We consider a trading framework where information has some idiosyncratic value for each consumer, exerts externalities and can be freely replicated and transmitted through links in a communication network. Prices paid for information are determined via the (asymmetric) Nash Bargaining Solution with endogenous disagreement points. This decentralized approach leads to unique prices and payoffs in any exogenous network. We use these payoffs to find connection structures that emerge under different externality regimes in pre-trade network formation stage. An application to citation graphs results in eigenvector-like measures of intellectual influence

Transient and intensive pharmacological immunosuppression fails to improve AAV-based liver gene transfer in non-human primates

BACKGROUND: Adeno-associated vectors (rAAV) have been used to attain long-term liver gene expression. In humans, the cellular immune response poses a serious obstacle for transgene persistence while neutralizing humoral immunity curtails re-administration. Porphobilinogen deaminase (PBGD) haploinsufficiency (acute intermittent porphyria) benefits from liver gene transfer in mouse models and clinical trials are about to begin. In this study, we sought to study in non-human primates the feasibility of repeated gene-transfer with intravenous administration of rAAV5 vectors under the effects of an intensive immunosuppressive regimen and to analyze its ability to circumvent T-cell immunity and thereby prolong transgene expression. METHODS: Three female Macaca fascicularis were intravenously injected with 1x1013 genome copies/kg of rAAV5 encoding the human PBGD. Mycophenolate mofetil (MMF), anti-thymocyte immunoglobulin, methylprednisolone, tacrolimus and rituximab were given in combination during 12 weeks to block T- and B-cell mediated adaptive immune responses in two macaques. Immunodeficient and immunocompetent mice were intravenously injected with 5x1012 genome copies/kg of rAAV5-encoding luciferase protein. Forty days later MMF, tacrolimus and rituximab were daily administrated to ascertain whether the immunosuppressants or their metabolites could interfere with transgene expression. RESULTS: Macaques given a rAAV5 vector encoding human PBGD developed cellular and humoral immunity against viral capsids but not towards the transgene. Anti-AAV humoral responses were attenuated during 12 weeks but intensely rebounded following cessation of the immunosuppressants. Accordingly, subsequent gene transfer with a rAAV5 vector encoding green fluorescent protein was impossible. One macaque showed enhanced PBGD expression 25 weeks after rAAV5-pbgd administration but overexpression had not been detected while the animal was under immunosuppression. As a potential explanation, MMF decreases transgene expression in mouse livers that had been successfully transduced by a rAAV5 several weeks before MMF onset. Such a silencing effect was independent of AAV complementary strand synthesis and requires an adaptive immune system. CONCLUSIONS: These results indicate that our transient and intensive pharmacological immunosuppression fails to improve AAV5-based liver gene transfer in non-human primates. The reasons include an incomplete restraint of humoral immune responses to viral capsids that interfere with repeated gene transfer in addition to an intriguing MMF-dependent drug-mediated interference with liver transgene expression