864 resultados para COMPETING OXYGEN TRANSFERS
Resumo:
The oxygen reduction reaction (ORR) was investigated on carbon-supported Pt-Co nanoparticle electrocatalysts with low Pt content in alkaline electrolyte. High resolution transmission electron microscopy, In situ X-ray absorption spectroscopy, and X-ray diffraction analysis evidenced large structural differences of the Pt-Co particles depending oil the route of the catalyst synthesis. It was demonstrated that although the Pt-Co materials contain low amounts of Pt, they show very good activities when the particles are formed by a Pt-rich shell and a Pt-Co core, which was obtained after submitting the electrocatalyst to a potential cycling in acid electrolyte. The high activity of this material was due to a major contribution from its higher surface area, as a result of the leaching of the Co atoms from the particle Surface. Furthermore, its high activity was ascribed to a minor contribution from the electronic interaction of the Pt atoms, at the particle surface, and the Co atoms located in the beneath layer, lowering the Pt cl-band center. As these electrocatalysts presented high activity for the ORR with low Pt content, the cost of the fuel cell cathodes could be lowered considerably. (c) 2009 Elsevier B.V. All rights reserved.
Resumo:
Despite rapid economic growth and poverty reduction, inequality in Chile has remained high and remarkably constant over the last 20 years, prompting academic and public interest in the subject. Due to data limitations, however, research on inequality in Chile has concentrated on the national and regional levels. The impact of cash subsidies to poor households on local inequality is thus not well understood. Using poverty-mapping methods to asses this impact, we find heterogeneity in the effectiveness of regional and municipal governments in reducing inequality via poverty-reduction transfers, suggesting that alternative targeting regimes may complement current practice in aiding the poor.
Resumo:
Externai debt service requires a dual resource transfer. Trade surpluses have to be generated in order to make foreign exchange revenues available for debt repayment. In addition, with developing countries' externai debt being largely a public liability, debt service requires that resources can be effectively transferred from the private to the public sector. This paper derives a statistical model for dealing with dual constraints in the presence of binary dependent variables and applies it to the dual resource transfer problem. The results from the estimation of the model for a sample of 31 middle-income developing countries in the period of 1980 to 1990, strongly support the hypothesis that both externai and fiscal constraints are important in explaining externai debt service disruptions.
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We study the effects of a conditional transfers program on school enrollment and performance in Mexico. We provide a theoretical framework for analyzing the dynamic educational decision and process inc1uding the endogeneity and uncertainty of performance (passing grades) and the effect of a conditional cash transfer program for children enrolled at school. Careful identification of the program impact on this model is studied. This framework is used to study the Mexican social program Progresa in which a randomized experiment has been implemented and allows us to identify the effect of the conditional cash transfer program on enrollment and performance at school. Using the mIes of the conditional program, we can explain the different incentive effects provided. We also derive the formal identifying assumptions needed to provide consistent estimates of the average treatment effects on enrollment and performance at school. We estimate empirically these effects and find that Progresa had always a positive impact on school continuation whereas for performance it had a positive impact at primary school but a negative one at secondary school, a possible consequence of disincentives due to the program termination after the third year of secondary school.
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This article first presents an econometric study suggesting that intergovernmental transfers to Brazilian municipalities are strongly partisan motivated. In light of that stylized fact, it develops an extension to Rogoff (1990)’s model to analyze the effect of partisan motivated transfers into sub-national electoral and fiscal equilibria. The main finding is that important partisan transfers may undo the positive selection aspect of political budget cycles. Indeed, partisan transfers may, on one hand, eliminate the political budget cycle, solving a moral hazard problem, but, on the other hand, they may retain an incompetent incumbent in office, bringing about an adverse selection problem.
Resumo:
This paper develops a two-period model with heterogeneous agents to analyze the e¤ects of transfers across locations on convergence, growth and welfare. The model has two important features. First, locations are asymmetric as it is assumed that there are more specialized occupations in the more developed one. Second, the returns on the investment to acquire new technology depend positively on the level of each region’s knowledge and on the level of the world knowledge assumed to be available to all. In one hand, the poor region has a disadvantage as it has a lower stock of knowledge. On the other hand, it has the advantage of not having yet exploited a greater stock of useable knowledge available in the world. Hence, there are two possible cases. When the returns are greater in the poor region, we obtain the following results: (i) the rich location grows slower; (ii) the transfers to the poor location enhances the country’s growth rate; and (iii) there is a positive amount of transfers to the poor region that is welfare improving. When the returns are greater in the rich region, the …rst two results are reversed and transfers to the rich region are welfare improving. In both cases, the optimal amount of transfer increases with the level of income disparity across regions and is not dependent on the level of the country’s economic development (measured by its income per capita). Barriers to the adoption of new technology available in the world can constrain the convergence process as it harms in greater length the poor region. The results do not change whether migration is allowed or not.
Resumo:
Cash transfers targeted to poor people, but conditional on some behavior on their part, such as school attendance or regular visits to health care facilities, are being adopted in a growing number of developing countries. Even where ex-post impact evaluations have been conducted, a number of policy-relevant counterfactual questions have remained unanswered. These are questions about the potential impact of changes in program design, such as benefit levels or the choice of the means-test, on both the current welfare and the behavioral response of household members. This paper proposes a method to simulate the effects of those alternative program designs on welfare and behavior, based on microeconometrically estimated models of household behavior. In an application to Brazil’s recently introduced federal Bolsa Escola program, we find a surprisingly strong effect of the conditionality on school attendance, but a muted impact of the transfers on the reduction of current poverty and inequality levels.
Resumo:
This study assesses the impact of unconditional transfer resources on the health indicators of Brazilian municipalities. This transfer refers to the Participation Fund of Municipalities (FPM) where at least 15% of its value should be spent on public health. Based on a discontinuity of the rules of transfers, we explore Regression Discontinuous Design for the years 2002 to 2010, and find: (i) no significant effect of FPM on mortality reduction; (ii) a robust and significant reduction in morbidity, treated municipalities – on the right side of thresholds – on average have a per capita rate of morbidity 0.00821% lower than those on the left side of the cutoff points; (iii) the mechanisms through which a reduction on morbidity could be operated would be due to estimated increases in preventive measures such as consultations and medical and nurses visits, these were bigger for the treated group in, respectively, 0.32%, 0.038% and 0.039%.
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We estimate the effects of unconditional (full fiscal decentralization) versus conditional (partial fiscal decentralization) block grants on local public spending in Brazilian municipalities. Our results suggest that the effect of unconditional and conditional transfers do not differ statistically. Their combination promotes a full crowding-in effect on aggregate public spending — i.e., for $1 of unconditional and conditional grant receipts; we find $1 of additional local public expenditures, greater than the corresponding effect of local income, providing further evidence for the flypaper effect. Moreover, the effect of unconditional transfers on education (health) spending is smaller than the effect of conditional education (health) transfers but greater than the corresponding effect of local income. We consider four strategies to identify causal effects of federal grants and the local income on fiscal responses regarding Brazilian local governments: (i) a fuzzy regression discontinuity design, (ii) Redistributive rules of education funds, (iii) Oil and Gas production, and (iv) Rainfall deviations from the historical mean.
Resumo:
This paper investigates the long-term e ects of conditional cash transfers on school attainment and child labor. To this end, we construct a dynamic heterogeneous agent model, calibrate it with Brazilian data, and introduce a policy similar to the Brazilian Bolsa Fam lia. Our results suggest that this type of policy has a very strong impact on educational outcomes, sharply increasing primary school completion. The conditional transfer is also able to reduce the share of working children from 22% to 17%. We then compute the transition to the new steady state and show that the program actually increases child labor over the short run, because the transfer is not enough to completely cover the schooling costs, so children have to work to be able to comply with the program's schooling eligibility requirement. We also evaluate the impacts on poverty, inequality, and welfare.
Resumo:
This paper investigates income tax revenues response to tax rate changes taking into consideration that cash-cum-in-kind transfers are used as a redistributive package to the community. First, we show that when cash and in-kind transfers are not tied to be substitute instruments, a marginal income tax increase may unambiguously decrease the quantity supplied of labor (and tax revenues therein). Next, we show that whenever the government chooses the optimum provision for the publicly provided good the tax revenue function has a negatively-sloped part with respect to tax rates except for one case. Last, we consider Brazilian data - PNAD - from 1976 to 2008 to test our theoretical implications. Our estimations suggest a weak evidence in favor of the existence of a La er-type curve for Brazilian income tax revenues data. Moreover, wend that the actual average income tax rate seems to be below the estimated optimum level. In a shorter sample from 1996-1999, we nd evidence that labor supply decreases with tax rate when cash and in-kind transfers are in play. Using a pseudo-panel from the same shorter sample, we try to estimate the elasticity of taxable income, following Creedy and Gemmell (2012) and Saez et al. (2009). We explore a small tax reform between 1997 and 1998 that a ected only the higher income tax bracket, and evidence that Brazil is on the revenue reducing side of the La er Curve, at least for individuals in the higher income tax bracket.
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This work had to verify the influence of massará, while mortar component, in the process of formation of saltpeter in cementitious plaster walls of buildings. The massará is a ceramic material, texture areno usually found in large volumes argillaceous sediments in Teresina, Piaui State capital, which is associated with the Portland cement mortar form for fixing and finishing in construction. Saltpeter or flowering is a pathology that happens in gypsum wallboard, which invariably reaction between soluble salts present in materials, water and oxygen. This pathology, supposedly credited to massará caused its use to suffer significant reduction in the market of the buildings. Verify this situation with particular scientific rigor is part of the proposal of this work. Grading tests Were performed, consistency limits (LL, LP and IP), determination of potential hydrogen, capacity Exchange (CTC), electrical conductivity (EC), x-ray fluorescence (FRX) and x-ray diffraction (DRX). Massará analysed samples in number six, including sample plastering salitrado presented potential hydrogen medium 5.7 in water and 5.2 on KCl n and electrical conductivity (EC), equal to zero. These results pointed to the affirmative that massará is a material that does not provide salinity content that can be taken into consideration. It is therefore concluded that the material analyzed not competing, at least with respect to the presence of soluble salts, for the formation of saltpeter