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Contribuições ao estudo da influência de propriedades de agregados no comportamento de misturas asfálticas densas; Contributions to the study of effects of aggregate properties on mechanical behavior of hot mix asphalt (HMA)

Gouveia, Lilian Taís de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/12/2006 Português
Relevância na Pesquisa
36.11%
O objetivo principal desta pesquisa é avaliar a influência que as propriedades estudadas dos agregados exercem sobre propriedades volumétricas e mecânicas de misturas asfálticas densas. Para tanto, foram avaliadas as propriedades de consenso e de origem, especificadas pelo Superpave, de um conjunto de agregados, além de suas densidades, porosidade, absorção e adesividade. Foram estudados agregados de gabro, basalto e areia natural e três tipos de granulometrias, uma denominada AZR, passando acima da zona de restrição da especificação Superpave, e outras duas, obtidas através do sistema de seleção granulométrica Bailey. Também três níveis de energia de compactação foram aplicados às misturas, 75, 110 e 155 golpes por face do corpo-de-prova Marshall. Avaliou-se o comportamento mecânico das misturas através dos ensaios de estabilidade e fluência Marshall, fluência por compressão uniaxial uniforme, fluência por compressão uniaxial dinâmica, resistência à tração, módulo de resiliência e fadiga. Os resultados mostraram que, de uma maneira geral, o agregado de gabro apresentou superioridade em relação ao agregado de basalto e de areia natural, tanto quando analisado isoladamente como quando analisado nas misturas asfálticas. Suas características de forma...

Testing Consumption Optimality using Aggregate Data

Gomes, Fábio Augusto Reis; Issler, João Victor
Fonte: Escola de Pós-Graduação em Economia da FGV Publicador: Escola de Pós-Graduação em Economia da FGV
Tipo: Relatório
Português
Relevância na Pesquisa
46.07%
The objective of this paper is to test for optimality of consumption decisions at the aggregate level (representative consumer) taking into account popular deviations from the canonical CRRA utility model rule of thumb and habit. First, we show that rule-of-thumb behavior in consumption is observational equivalent to behavior obtained by the optimizing model of King, Plosser and Rebelo (Journal of Monetary Economics, 1988), casting doubt on how reliable standard rule-of-thumb tests are. Second, although Carroll (2001) and Weber (2002) have criticized the linearization and testing of euler equations for consumption, we provide a deeper critique directly applicable to current rule-of-thumb tests. Third, we show that there is no reason why return aggregation cannot be performed in the nonlinear setting of the Asset-Pricing Equation, since the latter is a linear function of individual returns. Fourth, aggregation of the nonlinear euler equation forms the basis of a novel test of deviations from the canonical CRRA model of consumption in the presence of rule-of-thumb and habit behavior. We estimated 48 euler equations using GMM, with encouraging results vis-a-vis the optimality of consumption decisions. At the 5% level, we only rejected optimality twice out of 48 times. Empirical-test results show that we can still rely on the canonical CRRA model so prevalent in macroeconomics: out of 24 regressions...

Testing Consumption Optimality using Aggregate Data*

Gomes, Fábio Augusto Reis; Issler, João Victor
Fonte: Escola de Pós-Graduação em Economia da FGV Publicador: Escola de Pós-Graduação em Economia da FGV
Tipo: Relatório
Português
Relevância na Pesquisa
46.02%
This paper tests the optimality of consumption decisions at the aggregate level taking into account popular deviations from the canonical constant-relative-risk-aversion (CRRA) utility function model-rule of thumb and habit. First, based on the critique in Carroll (2001) and Weber (2002) of the linearization and testing strategies using euler equations for consumption, we provide extensive empirical evidence of their inappropriateness - a drawback for standard rule- of-thumb tests. Second, we propose a novel approach to test for consumption optimality in this context: nonlinear estimation coupled with return aggregation, where rule-of-thumb behavior and habit are special cases of an all encompassing model. We estimated 48 euler equations using GMM. At the 5% level, we only rejected optimality twice out of 48 times. Moreover, out of 24 regressions, we found the rule-of-thumb parameter to be statistically significant only twice. Hence, lack of optimality in consumption decisions represent the exception, not the rule. Finally, we found the habit parameter to be statistically significant on four occasions out of 24.

A Bayesian Multi-level model for estimating the diet/disease relationship in a multicenter study with exposures measured with error: the EPIC study

Ferrari, Pietro; Carroll, Raymond J; Gustafson, Paul; Riboli, Elio
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 20/12/2008 Português
Relevância na Pesquisa
36.18%
In a multicenter study, the overall relationship between diet and cancer risk can be broken down into: [a] within-center relationships, which reflect the relationships at the individual level in each of the centers, and [b] a between-center relationship, which captures the association between exposure and disease risk at the aggregate level. In this work, we propose the use of a Bayesian multilevel model that takes into account the within- and between-center levels of evidence, using information at the individual and aggregate level. Correction for measurement error is performed in order to correct for systematic between-center measurement error in dietary exposure, and for attenuation biases in relative risk estimates within centers. The estimation of the parameters is carried out in a Bayesian framework using Gibbs sampling. The model entails a measurement, an exposure, and a disease component. Within the European Prospective Investigation into Cancer and Nutrition (EPIC) the association between lipid intake, assessed through dietary questionnaire and 24-hour dietary recall, and breast cancer incidence was evaluated. This analysis involved 21,534 women and 334 incident breast cancer cases from the EPIC calibration study. In this study...

Aggregate versus day level association between methamphetamine use and HIV medication non-adherence among gay and bisexual men

Parsons, Jeffrey T.; Kowalczyk, William; Botsko, Michael; Tomassilli, Julia; Golub, Sarit A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/2013 Português
Relevância na Pesquisa
36.15%
Methamphetamine use is associated with HIV infection, especially among gay and bisexual men. Methamphetamine use contributes to disease progression both directly, by increasing viral load and damaging the immune system, and indirectly, by decreasing medication adherence. Research examining the association of methamphetamine use and non-adherence has traditionally compared groups of users and nonusers on adherence, compared methamphetamine use between participants above or below some threshold level of adherence (e.g. >90% dose adherence), or examined aggregate relationships. Using Timeline Follow-back procedures, the present study examined aggregate, threshold, and day-level associations of methamphetamine use with non-adherence in 210 HIV-positive gay and bisexual methamphetamine-using men. Methamphetamine use was not associated with adherence behavior at the aggregate-level, but methamphetamine use on a given day was associated with 2.3 times the odds of non-adherence on that day. Threshold results were equivocal. These data suggest that the methamphetamine and non-adherence relationship is complicated: non-adherence is more likely to occur on days in which methamphetamine is used, but participants reported more non-adherence days in which methamphetamine was not used. This seeming paradox generates questions about the selection of analytical techniques and has important implications for behavioral interventions targeting substance use and adherence among HIV-positive individuals.

Zooming In : From Aggregate Volatility to Income Distribution

Calderón, César; Yeyati, Eduardo Levy
Fonte: Banco Mundial Publicador: Banco Mundial
Português
Relevância na Pesquisa
36.12%
In contrast with a growing literature on the drivers of aggregate volatility in developing countries, its consequences in terms of individual incomes have received less attention. This paper looks at the impact of cyclical output fluctuations and extreme output events (crises) on unemployment, poverty, and inequality. The authors find robust evidence that aggregate volatility has a regressive, asymmetric, and non linear impact, as reflected in the strong influence of extreme output drops. The findings show that, in addition to the mitigating role of personal wealth, public expenditure and labor protection exert a similar benign effect. These findings are in line with the income substitutions view of social safety nets, and cast a new light on the value of social programs and labor market regulation in crisis prone developing countries.

Social Impacts of Climate Change in Peru : A District Level Analysis of the Effects of Recent and Future Climate Change on Human Development and Inequality

Andersen, Lykke E.; Suxo, Addy; Verner, Dorte
Fonte: Banco Mundial Publicador: Banco Mundial
Português
Relevância na Pesquisa
56.05%
This paper uses district level data to estimate the general relationship between climate, income and life expectancy in Peru. The analysis finds that both incomes and life expectancy show hump-shaped relationships, with optimal average annual temperatures around 18-20ºC. These estimated relationships were used to simulate the likely effects of both past (1958-2008) and future (2008-2058) climate change. At the aggregate level, future climate change in Peru is estimated to cause a small reduction in average life expectancy of about 0.2 years. This average, however, hides much larger losses in the already hot areas as well as substantial gains in currently cold areas. Similarly, the average impact on incomes is a modest reduction of 2.3 percent, but with some districts experiencing losses of up to 20 percent and others gains of up to 13 percent. Future climate change is estimated to cause an increase in poverty (all other things equal), but to have no significant effect on the distribution of incomes.

Does Employment Generation Really Matter for Poverty Reduction?

Gutierrez, Catalina; Orecchia, Carlo; Paci, Pierella; Serneels, Pieter
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
36.19%
This paper analyzes how the employment/productivity profile of growth and its sectoral pattern are correlated with poverty reduction. The authors use a sample of 104 short-run growth spells in developing countries, between 1980 and 2001. They also identify some conditions of the labor market and the economic environment that are associated with employment-intensive growth or specific sectoral growth. The results show that, in the short run, although the aggregate employment-rate intensity of growth does not matter for poverty reduction any more than the aggregate productivity intensity of growth, the sectoral pattern of employment growth and productivity growth is important. Employment-intensive growth in the secondary sector is associated with decreases in poverty, while employment-intensive growth in agriculture is correlated with poverty increases. Similarly, productivity-intensive growth in agriculture is associated with decreases in poverty. Although the study does not address causality, coincidence of these phenomena in this large sample of heterogeneous countries and periods suggests that...

Governance Matters V : Aggregate and Individual Governance Indicators for 1996–2005

Kaufmann, Daniel; Kraay, Aart; Mastruzzi, Massimo
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
36.11%
The authors report on the latest version of the worldwide governance indicators, covering 213 countries and territories and measuring six dimensions of governance from 1996 until end-2005: voice and accountability, political stability and absence of violence, government effectiveness, regulatory quality, rule of law, and control of corruption. The latest indicators are based on hundreds of variables and reflect the views of thousands of citizen and firm survey respondents and experts worldwide. Although global averages of governance display no marked trends during 1996-2005, nearly one-third of countries exhibit significant changes [for better or for worse] on at least one dimension of governance. Three new features distinguish this update. (1) The authors have moved to annual reporting of governance estimates. This update includes new governance estimates for 2003 and 2005, as well as minor backward revisions to biannual historical data for 1996-2004. (2) The authors are, for the first time, publishing the individual measures of governance from virtually every data source underlying the aggregate governance indicators. The ready availability of the individual data sources underlying the aggregate governance indicators is aimed at further enhancing the transparency of the methodology and of the resulting aggregate indicators...

Causes and Consequences of Civil Strife : Micro-Level Evidence from Uganda

Deininger, Klaus
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
46.15%
To bridge the gap between case studies and highly aggregate cross-country analyses of civil unrest, the author uses data from Uganda to explore determinants of civil strife (as contrasted to theft and physical violence) at the community level, as well as the potentially differential impact of these variables on investment and nonagricultural enterprise formation at the household level. He finds that distance from infrastructure (a proxy for scarcity of economic opportunities and government investment), asset inequality (social tension), the presence of cash crops (expropriable wealth), and lower levels of human capital (ability to take advantage of opportunities in the "regular" economy) all increase the propensity for civil strife. Furthermore, civil strife, in marked contrast to violence and theft, reduces investment and nonagricultural enterprise start-ups.

A Poverty Analysis Macroeconomic Simulator (PAMS) Linking Household Surveys with Macro-Models

Pereira da Silva, Luiz A.; Essama-Nssah, B.; Samake, Issouf
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
36.19%
The Poverty Analysis Macroeconomic Simulator (PAMS) is a model that links standard household surveys with macro frameworks. It allows users to assess the effect of macroeconomic policies-in particular, those associated with Poverty Reduction Strategies papers-on sectoral employment and income, the incidence of poverty, and income distribution. PAMS (in Excel) has three interconnected components: (1) A standard aggregate macro-framework that can be taken from any macro-consistency model (for example, RMSM-X, 123) to project GDP, national accounts, the national budget, the BoP, price levels, and so on, in aggregate consistent accounts. (2) A labor market model breaking down labor categories by skill level and economic sectors whose production total is consistent with that of the macro framework. Individuals from the household surveys are grouped in representative groups of households defined by the labor category of the head of the household. For each labor category, labor demand depends on sectoral output and real wages. Wage income levels by economic sector and labor category can thus be determined. In addition...

Policy Responses to a Dark Side of the Integration of Regions

Stark, Oded
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: ResearchPaper
Português
Relevância na Pesquisa
36.14%
In his paper I study policy responses to an increase in post-merger distress. I consider the integration of regions as a merger of populations which I view as a revision of social space, and I identify the effect of the merger on aggregate distress. The paper is based on the premise that the merger of groups of people alters their social landscape and their comparators. Employing a specific measure of social distress that is based on the sensing of relative deprivation, a merger increases aggregate distress: the social distress of a merged population is greater than the sum of the social distress of the constituent populations when apart. In response, policies are enacted to ensure that aggregate distress and/or that of individuals does not rise after a merger. I consider two publicly-financed, cost-effective policies designed so as not to reduce individuals’ incomes: a policy that reverses the negative effect of the merger on the aggregate level of relative deprivation, bringing it back to the sum of the pre-merger levels of aggregate relative deprivation of the two populations when apart; and a policy that is aimed at retaining the relative deprivation of each individual at most at its pre-merger level. These two policies are developed as algorithms. Numerical examples illustrate the application of the algorithms.

The Poverty Impacts of the Doha Round in Cameroon : The Role of Tax Policy

Emini, Christian Arnault; Cockburn, John; Decaluwe, Bernard
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
Português
Relevância na Pesquisa
36.12%
The authors aim to assess the possible impacts of the Doha Round of negotiations on poverty in Cameroon. During the recent period of economic recovery, Cameroon enjoyed a sharp decline in poverty, with the headcount index falling from 53.3 percent of inhabitants in 1996 to 40.2 percent in 2001, mostly due to economic growth rather than redistribution. Will the current trade negotiations under the Doha Round reinforce or curb this trend? They apply a computable general equilibrium (CGE) microsimulation model that involves 10,992 households in order to address this question. The authors find the Doha Round to be poverty-reducing for Cameroon. For the whole country, the estimate of the net number of people who are lifted out of poverty is 22,000 following this scenario. Further investigations indicate that more ambitious world trade liberalization leads to greater poverty alleviation at the national level, while Cameroon's domestic trade liberalization has adverse poverty and inequality impacts-despite giving rise to higher aggregate welfare. Under the Doha scenario, the cuts in Cameroon's tariffs are very small (the average tariff rate moves from 11.79 percent in the base run to merely 11.66 percent) so that world trade liberalization effects on prices more than offset the adverse own liberalization effects in this scenario. If the rest of the world and Cameroon full trade liberalizations are combined...

Markups, Returns to Scale, and Productivity: A Case Study of Singapore's Manufacturing Sector

Kee, Hiau Looi
Fonte: World Bank, Washington, D.C. Publicador: World Bank, Washington, D.C.
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
Português
Relevância na Pesquisa
36.12%
The results of this paper challenge the conventional wisdom in the literature that productivity plays no role in the economic development of Singapore. Properly accounting for market power and returns to scale technology, the estimated average productivity growth is twice as large as the conventional total factor productivity (TFP) measures. Using a standard growth accounting (production function) technique, Young (1992, 1995) found no sign of TFP growth in the aggregate economy and the manufacturing sector of Singapore. Based on Young's results, Krugman (1994) claimed that there was no East Asia miracle as all the economic growth in Singapore could be attributed to its capital accumulation in the past three decades. Citing evidence on nondiminishing market rates of return to capital investment in Singapore during the period of fast growth as an indication of high productivity growth, Hsieh (1999) challenged Young's findings using the dual approach. But all of these papers maintained the assumptions of perfect competition and constant returns to scale and used only aggregate macro-level data. Kee uses industry level data and focuses on Singapore's manufacturing sector. She develops an empirical methodology to estimate industry productivity growth in the presence of market power and nonconstant returns to scale. The estimation of industry markups and returns to scale in this paper combines both the production function (primal) and the cost function (dual) approaches while controlling for input endogeneity and selection bias. The results of a fixed effect panel regression show that all industries in the manufacturing sector violate at least one of the two assumptions. Relaxing the assumptions leads to an estimated productivity growth that is on average twice as large as the conventional TFP calculation. Kee concludes that productivity growth plays a nontrivial role in the manufacturing sector.

Export Diversi cation in a Transitioning Economy : The Case of Syria

Lim, Jamus Jerome; Saborowski, Christian
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
Português
Relevância na Pesquisa
46.04%
How does the process of export diversification play out in a transitioning economy, especially in light of government policy aimed at trade liberalization? This paper examines this question by considering a directed policy effort by Syria -- an economy transitioning from both economic centralization and resource dependence -- to liberalize its trade in 2001. In addition to documenting the patterns of diversification at the aggregate level since the implementation of the policy, we also examine factors that are related to diversification at the sectoral level. Our findings suggest that, while Syria has achieved reasonably rapid export diversification, this may to a large extent be the result of structural transformations in the economy, and that further consolidation of diversification gains may require continued policy reform along the lines of strengthening Syria's weak institutional and business environment.

Colombia - National Level Public Financial Management and Procurement Report : Public Financial Management Performance; Colombia - Informe de la gestion financiera publica y sistema de contratacion

World Bank; Inter-American Development Bank
Fonte: World Bank Publicador: World Bank
Tipo: Economic & Sector Work :: Other Financial Sector Study
Português
Relevância na Pesquisa
36.14%
This Public Financial Management Performance Report (PFMPR) analyzes the performance of Colombia's public financial management (PFM) institutions, systems and processes. It documents areas where performance is close to or follows international good practice, as well as opportunities to further enhance PFM contribution to the goals of strengthening fiscal discipline, enabling more efficient allocation of resources, increasing operational efficiency, and fostering transparency. It is expected that the identified opportunities will strengthen further the Government of Colombia's programs of continuous PFM improvement, as provided for under the National Development Plan pillar regarding a state at the service of its citizens: efficient and effective Government. The main challenges cited in the report could also be an important reference to future development plans and PFM reforms. Ensuring the sustainability and trajectory of PFM programs becomes even more critical in the context of public expenditure policies to deal with the current international economic crisis. The study is based on the 28 high-level indicators and 69 individual dimensions that compose the PFM performance measurement framework. Each indicator seeks to measure performance of a key PFM element against a scale from A to D. The highest score is warranted for an individual indicator if the core PFM element meets the relevant objective in a complete...

Indonesia : Oil and Gas Sector Study

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Português
Relevância na Pesquisa
45.93%
This study attempts to provide a broad, first cut review of the most pressing issues facing the sector, and to recommend ways to ameliorate or eliminate the problems. The main problems are: 1) petroleum product prices are heavily subsidized at the aggregate level and distorted at relative levels, and thus need to be rationalized within an economic framework; 2) the functions and role of the state oil and gas company (Pertamina) are problematic, and therefore Pertamina must be fundamentally restructured to eliminate the conflicts of interest and inefficiencies; 3) some of the provisions of the production sharing contracts are relatively regressive and need to be re-evaluated with a view to maximize the contribution of the sector to the economy, and to increase upstream investment by the private sector; 4) existing laws and regulations are inadequate and must be replaced; 5) petroleum products are of poor quality and must be improved, particularly by phasing out the lead from gasoline; and 6) energy sector institutions are weak and must be strengthened. Although the issues are complex and sweeping changes are needed...

Do Workers’ Remittances Promote Financial Development?

Aggarwal, Reena; Demirgüç-Kunt, Asli; Martinez Peria, Maria Soledad
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
Português
Relevância na Pesquisa
45.98%
Workers' remittances to developing countries have become the second largest type of flows after foreign direct investment. The authors use data on workers' remittance flows to 99 developing countries from 1975-2003 to study the impact of remittances on financial sector development. In particular, they examine whether remittances contribute to increasing the aggregate level of deposits and credit intermediated by the local banking sector. This is an important question considering the extensive literature that has documented the growth-enhancing and poverty-reducing effects of financial development. The findings provide strong support for the notion that remittances promote financial development in developing countries.

Productivity or Endowments? Sectoral Evidence for Hong Kong's Aggregate Growth

Hiau Looi Kee
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
Português
Relevância na Pesquisa
46.02%
The author provides sectoral evidence that sheds new light on the current debate regarding the sources of growth of the East Asian miracle. The author tests both the productivity-driven and endowment-driven hypotheses using Hong Kong's sectoral data. The results show that most of the growth in the services sector is driven by the rapidly accumulating capital endowments, and not by productivity growth. In addition, productivity growth in the manufacturing sector is also unimpressive. The manufacturing sector is more labor intensive and its growth is hindered by the reallocation of resources into the services sector as a result of the growth of capital endowments and imports. Overall, sectoral evidence supports the endowment-driven hypothesis for Hong Kong's aggregate growth.

Socioeconomic factors and suicide rates at large-unit aggregate levels : a comment

Neumayer, Eric
Fonte: London School of Economics and Political Science Research Publicador: London School of Economics and Political Science Research
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em /12/2003 Português
Relevância na Pesquisa
36.12%
Can socioeconomic factors seemingly explain variation in suicide rates at large-unit aggregate levels only due to an ecological fallacy? This is what Kunce and Anderson (2002) suggest based on fixed-effects estimation of US state suicide rates, in which they find little evidence that socioeconomic factors matter. We demonstrate that this result does not hold true for other large-unit aggregate levels in our analysis of suicide at the cross-national level. We find that many socioeconomic factors have a statistically significant impact. We conclude that sociological and economic theories explaining variation in suicide rates at the large-unit aggregate level with the help of aggregate socioeconomic factors cannot simply be dismissed because of an alleged ecological fallacy.