Interpersonal interaction and economic theory: the case of public goods

Interpersonal interaction in public goods contexts is very different in character to its depiction in economic theory, despite the fact that the standard model is based on a small number of apparently plausible assumptions. Approaches to the problem are reviewed both from within and outside economics. It is argued that quick fixes such as a taste for giving do not provide a way forward. An improved understanding of why people contribute to such goods seems to require a different picture of the relationships between individuals than obtains in standard microeconomic theory, where they are usually depicted as asocial. No single economic model at present is consistent with all the relevant field and laboratory data. It is argued that there are defensible ideas from outside the discipline which ought to be explored, relying on different conceptions of rationality and/or more radically social agents. Three such suggestions are considered, one concerning the expressive/communicative aspect of behaviour, a second the possibility of a part-whole relationship between interacting agents and the third a version of conformism.

Evaluation of cumulative externality: environmental economics, oligopoly and the private provision of public goods

This paper evaluates environmental externality when the structure of the externality is cumulative. The evaluation exercise is based on the assumption that the agents in question form conjectural variations. A number of environments are encompassed within this classification and have received due attention in the literature. Each of these heterogeneous environments, however, possesses considerable analytical homogeneity and permit subscription to a general model treatment. These environments include environmental externality, oligopoly and the analysis of the private provision of public goods. We highlight the general analytical approach by focusing on this latter context, in which debate centers around four issues: the existence of free-riding, the extent to which contributions are matched equally across individuals, the nature of conjectures consistent with equilibrium, and the allocative inefficiency of alternative regimes. This paper resolves each of these issues, with the following conclusions: A consistent-conjectures equilibrium exists in the private provision of public goods. It is the monopolistic-conjectures equilibrium. Agents act identically, contributing positive amounts of the public good in an efficient allocation of resources. There is complete matching of contributions among agents, no free-riding, and the allocation is independent of the number of members within the community. Thus the Olson conjecture—that inefficiency is exacerbated by community size—has no foundation in a consistent-conjectures, cumulative-externality, context (212 words).

The social evolution of dispersal with public goods cooperation

Selection can favour the evolution of individually costly dispersal if this alleviates competition between relatives. However, conditions that favour altruistic dispersal also mediate selection for other social behaviours, such as public goods cooperation, which in turn is likely to mediate dispersal evolution. Here, we investigate – both experimentally (using bacteria) and theoretically – how social habitat heterogeneity (i.e. the distribution of public goods cooperators and cheats) affects the evolution of dispersal. In addition to recovering the well-known theoretical result that the optimal level of dispersal increases with genetic relatedness of patch mates, we find both mathematically and experimentally that dispersal is always favoured when average patch occupancy is low, but when average patch occupancy is high, the presence of public goods cheats greatly alters selection for dispersal. Specifically, when public goods cheats are localized to the home patch, higher dispersal rates are favoured, but when cheats are present throughout available patches, lower dispersal rates are favoured. These results highlight the importance of other social traits in driving dispersal evolution.

On the release of metronidazole from natural rubber latex membranes

The controlled release of drugs can be efficient if a suitable encapsulation procedure is developed, which requires biocompatible materials to hold and release the drug. In this study, a natural rubber latex (NRL) membrane is used to deliver metronidazole (MET), a powerful antiprotozoal agent. MET was found to be adsorbed on the NRL membrane, with little or no incorporation into the membrane bulk, according to energy dispersive X-ray spectroscopy. X-ray diffraction and FTIR spectroscopy data indicated that MET retained its structural and spectroscopic properties upon encapsulation in the NRL membrane, with no molecular-level interaction that could alter the antibacterial activity of MET. More importantly, the release time of MET in a NRL membrane in vitro was increased from the typical 6-8 h for oral tablets or injections to ca. 100 h. The kinetics of the drug release could be fitted with a double exponential function, with two characteristic times of 3.6 and 29.9 h. This is a demonstration that the induced angiogenesis known to be provided by NRL membranes can be combined with a controlled release of drugs, whose kinetics can be tailored by modifying experimental conditions of membrane fabrication for specific applications. (C) 2010 Elsevier B.V. All rights reserved.

Elastomeric Composites Based on Ethylene-Propylene-Diene Monomer Rubber and Conducting Polymer-Modified Carbon Black

Thermally stable elastomeric composites based on ethylene-propylene-diene monomer (EPDM) and conducting polymer-modified carbon black (CPMCB) additives were produced by casting and crosslinked by compression molding. CPMCB represent a novel thermally stable conductive compound made via ""in situ"" deposition of intrinsically conducting polymers (ICP) such as polyaniline or polypyrrole on carbon black particles. Thermogravimetric analysis showed that the composites are thermally stable with no appreciable degradation at ca. 300 degrees C. Incorporating CPMCB has been found to be advantageous to the processing of composites, as the presence of ICP lead to a better distribution of the filler within the rubber matrix, as confirmed by morphological analysis. These materials have a percolation threshold range of 5-10 phr depending on the formulation and electrical dc conductivity values in the range of 1 x 10(-3) to 1 x 10(-2) S cm(-1) above the percolation threshold. A less pronounced reinforcing effect was observed in composites produced with ICP-modified additives in relation to those produced only with carbon black. The results obtained in this study show the feasibility of this method for producing stable, electrically conducting composites with elastomeric characteristics. POLYM. COMPOS., 30:897-906, 2009. (C) 2008 Society of Plastics Engineers

Extraction of cellulose whiskers from cassava bagasse and their applications as reinforcing agent in natural rubber

In this work cassava bagasse, a by-product of cassava starch industrialization was investigated as a new raw material to extract cellulose whiskers. This by-product is basically constituted of cellulose fibers (17.5 wt%) and residual starch (82 wt%). Therefore, this residue contains both natural fibers and a considerable quantity of starch and this composition suggests the possibility of using cassava bagasse to prepare both starch nanocrystals and cellulose whiskers. In this way, the preparation of cellulose whiskers was investigated employing conditions of sulfuric acid hydrolysis treatment found in the literature. The ensuing materials were characterized by transmission electron microscopy (TEM) and X-ray diffraction experiments. The results showed that high aspect ratio cellulose whiskers were successfully obtained. The reinforcing capability of cellulose whiskers extracted from cassava bagasse was investigated using natural rubber as matrix. High mechanical properties were observed from dynamic mechanical analysis. (C) 2010 Elsevier B.V. All rights reserved.

Phenolic matrices and sisal fibers modified with hydroxy terminated polybutadiene rubber: Impact strength, water absorption, and morphological aspects of thermosets and composites

The aim of the present work was to investigate the toughening of phenolic thermoset and its composites reinforced with sisal fibers, using hydroxyl-terminated polybutadiene rubber (HTPB) as both impact modifier and coupling agent. Substantial increase in the impact strength of the thermoset was achieved by the addition 10% of HTPB. Scanning electron microscopy (SEM) images of the material with 15% HTPB content revealed the formation of some rubber aggregates that reduced the efficiency of the toughening mechanism. In composites, the toughening effect was observed only when 2.5% of HTPB was added. The rubber aggregates were found located mainly at the matrix-fiber interface suggesting that HTPB could be used as coupling agent between the sisal fibers and the phenolic matrix. A composite reinforced with sisal fibers pre-impregnated with HTPB was then prepared; its SEM images showed the formation of a thin coating of HTPB on the surface of the fibers. The ability of HTBP as coupling agent between sisal fibers and phenolic matrix was then investigated by preparing a composite reinforced with sisal fibers pre-treated with HTPB. As revealed by its SEM images, the HTPB pre-treatment of the fibers resulted on the formation of a thin coating of HTPB on the surface of the fibers, which provided better compatibility between the fibers and the matrix at their interface, resulting in a material with low water absorption capacity and no loss of impact strength. (C) 2009 Elsevier B.V. All rights reserved.

Graphite-silicone rubber composite electrode: Preparation and possibilities of analytical application

Composite electrodes were prepared using graphite powder and silicone rubber in different compositions. The use of such hydrophopic materials interned to diminish the swallowing observed in other cases when the electrodes are used in aqueous solutions for a long time. The composite was characterized for the response reproducibility, ohmic resistance, thermal behavior and active area. The voltammetric response in relation to analytes with known voltammetric behavior was also evaluated, always in comparison with the glassy carbon. The 70% (graphite, w/w) composite electrode was used in the quantitative determination of hydroquinone (HQ) in a DPV procedure in which a detection limit of 5.1 x 10(-8) mol L-1 was observed. HQ was determined in a photographic developer sample with errors lower then 1% in relation to the label value. (c) 2007 Elsevier B.V. All rights reserved.

THE POTENTIALITIES OF USING A GRAPHITE-SILICONE RUBBER COMPOSITE ELECTRODE IN THE DETERMINATION OF PROPRANOLOL

A graphite silicone-rubber composite electrode (GSR) was used for the determination of propranolol in drug formulation. Cyclic voltammetry (CV) at the GSR presented an irreversible oxidation peak at + 0.8V vs. SCE, in Britton Robinson (B-R) buffer pH 7.4. The quantitative determination was carried out using differential pulse voltammetry (DPV). Under optimized parameters a linear dynamic range from 5.0 to 80.6 mu mol L(-1) with a detection limit of 1.1 mu mol L(-1) was observed. A repeatability of 4.5 +/- 0.1 mu A (n = 10) peak current was found after 10 successive DPV voltammograms of propranolol in the same solution after surface renovations. Using the proposed electrode, propranolol was quantified in a pharmaceutical formulation with results that agreed within 95% confidence level (t-test) with those from an official method.

Analytical Potentialities of Carbon Nanotube/Silicone Rubber Composite Electrodes: Determination of Propranolol

A new composite electrode based on multiwall carbon nanotubes (MWCNT) and silicone-rubber (SR) was developed and applied to the determination of propranolol in pharmaceutical formulations. The effect of using MWCNT/graphite mixtures in different proportions was also investigated. Cyclic voltammetry and electrochemical impedance spectroscopy were used for electrochemical characterization of different electrode compositions. Propranolol was determined using MWCNT/SR 70% (m/m) electrodes with linear dynamic ranges up to 7.0 mu molL(-1) by differential pulse and up to 5.4 mu molL(-1) by square wave voltammetry, with LODs of 0.12 and 0.078 mu molL(-1), respectively. Analysis of commercial samples agreed with that obtained by the official spectrophotometric method. The electrode is mechanically robust and presented reproducible results and a long useful life.

Welfare and fiscal policy with public goods and infrastructure

We construct and simulate a model to study the welfare and macroeconomic impact of government actions when its productive role is taken into account. The trade-off between public investment and public consumption is also investigated, since public consumption is introduced as a public good that directly affects individuals' well-being. Our results replicate econometric evidence showing that part of the observed slowdown of U.S. productivity growth can be explained by the reduction of investment in infrastructure which also implied a sizable welfare 1085 to the popu1ation. Depending on the methodology used we found a welfare cost ranging from 4.2% to 1.16% of GNP. The impact of fiscal policy can be qualitative and quantitative distinct depending on Whether we assume a higher or smaller output elasticity to infrastructure. If it is high enough, increases in tax rates may stimulate accumulation and production, which is the opposite prediction of standard ncocJassica1 models.

Yet another reason to tax goods

The optimal taxation of goods, labor and capital income is considered in a two period model where: i) private information changes through time; ii) savings are not observed, and; iii) savings a§ect preferences conditional on the realization of types. The simultaneous appearance of these three elements cause optimal commodity taxes to depend on o§-equilibrium savings. As a consequence, separability no longer su¢ ces for the uniform taxation prescription of Atkinson and Stiglitz (AS) to obtain. If preferences are homothetic AS is partially restored: taxes are uniform within periods, however, future consumption is taxed at a higher rate than current consumption.

Um modelo exploratório para o processo de compra de MRO baseadas na internet Michelin Brasil

A presente dissertação tem por objetivo criar um modelo de compras de rMRO (manutenção, reparos e operações) baseado na Internet, para a Michelin no Brasil. Atualmente, a empresa Michelin está participando de uma comunidade virtual, sob a forma de um "vertal", criada pelas maiores empresas da indústria de pneu e borracha (Michelin, Goodyear, Pirelli, Continental, Cooper, Sumitomo, entre outras), e cuja intenção é desenvolver uma praça de mercado global para realização das suas compras e aprovisionamentos. A Rubbernetwork.com (RNC) foi fundada como uma empresa independente, reunindo o conjunto das compras da indústria de pneu e borracha, representando um valor de mais de cinqüenta bilhões de dólares por ano gastos em matérias-primas, equipamentos, maquinário, bens e serviços. Esta central de compras permitirá a seus membros aumentar a eficácia de suas operações e realizar economias substanciais nos custos de transação. Cada transação será protegida por apropriados sistemas advindos da implementação da tecnologia da informação, a fim de garantir a confidencialidade de todas as atividades comerciais de cada empresa individualmente. Os membros participantes estão convencidos de que a iniciativa possibilitará economias significativas e melhorará a eficiência de suas cadeias de valor. A comunidade virtual será aberta a todos os fabricantes e fornecedores relacionados à indústria de pneu e borracha, sendo também bem vindas oportunidades 2 de interação com outras comunidades virtuais, especialmente aquelas associadas à indústria automotiva. É dentro do contexto de implementação do projeto Rubbernetwork.com (RNC) que a dissertação se desenvolverá, tecendo estratégias e modelos de negócios concernentes aos processos de compras relacionados a MRO (manutenção, reparos e operações). O desenvolvimento de um "vertal" na Internet não impede que portais horizontais complementares, e não excludentes, sejam também acrescidos como alternativa de negócios. Há de se dar um tratamento específico às compras diárias que envolvem um grande número de diferentes fornecedores, várias áreas internas na empresa e consomem tempo desnecessário em trabalhos burocráticos, sem fins estratégicos. Cabe ressaltar que tal categoria de compras, denominada MRO, apesar de seu baixo valor por produto ou serviço adquirido, gera um elevado volume de transações e um alto impacto operacional. Pelo fato de tratar-se de uma experiência inovadora em setor de características próprias - mercado de pneu e borracha -, e de estar-se criando uma expectativa de cooperação entre empresas concorrentes, em busca da racionalização do processo de compras e divisão de custos operacionais, a metodologia utilizada, quanto aos seus fins, será exploratória e aplicada I. Quanto aos meios de investigação, a pesquisa realizada será: de campo, estudo de caso e bibliográfica. O universo da pesquisa restringir-se-á à empresa Michelin, onde o processo de compras de MRO baseado na Internet será contemplado, através de levantamento de dados nos E.UA e França, a fim de propor-se um modelo para a Michelin Brasil.

Municipalities secession and uncertainty on public goods provision

This paper investigates the causes of municipalities secession in Brazil. The theoretical model proposes that the median voter is not fully informed about the efficiency effect of secession on public good provision and uses the break up decision undertaken by neighbor’s municipalities within the state to account for his voting. Our empirical results confirms that prediction

Trade in intermediate goods and total factor productivity

We develop and calibrate a model where differences in factor endowments lead countries to trade intermediate goods, and gains from trade reflect in total factor productivity. We perform several output and growth decompositions, to assess the impact that barriers to trade, as well as changes in terms of trade, have on measured TFP. We find that for very poor economies gains from trade are large, in some cases representing a doubling of GDP. Also, that an improvement in the terms of trade - by allowing the use of a better mix of intermediate inputs in the production process - translates into productivity growth.