Comparison between two surgical techniques for root coverage with an acellular dermal matrix graft

Aim: The aim of this randomized, controlled, clinical study was to compare two surgical techniques with the acellular dermal matrix graft (ADMG) to evaluate which technique could provide better root coverage. Material and Methods: Fifteen patients with bilateral Miller Class I gingival recession areas were selected. In each patient, one recession area was randomly assigned to the control group, while the contra-lateral recession area was assigned to the test group. The ADMG was used in both groups. The control group was treated with a broader flap and vertical-releasing incisions, and the test group was treated with the proposed surgical technique, without releasing incisions. The clinical parameters evaluated before the surgeries and after 12 months were: gingival recession height, probing depth, relative clinical attachment level and the width and thickness of keratinized tissue. Results: There were no statistically significant differences between the groups for all parameters at baseline. After 12 months, there was a statistically significant reduction in recession height in both groups, and there was no statistically significant difference between the techniques with regard to root coverage. Conclusions: Both surgical techniques provided significant reduction in gingival recession height after 12 months, and similar results in relation to root coverage.

Bullied by Budgets, Pushed by Patrons, Driven by Demand: Libraries and Tantalizing Technologies

Libraries are caught in the middle—between static or shrinking budgets on one hand and ever-expanding user needs on the other. How did we get here, and where do we go from here? This paper will offer two perspectives: Part I will present survey results about changing Library purchasing habits in light of changing formats, access, business models and user demands. Data from a previous survey on this topic will be compared and updated. Pricing trends and possible futures will be discussed. Part II will briefly trace the history of libraries’ roles in scholarly communication and connecting learners with knowledge. From there, we show an example of phasing in a patron-driven / demand-driven and short-term loan e-book program, complete with incorporating these tools in library instruction, research, and portable device loadability for field work.

Índices antecedentes e coincidentes da atividade econômica brasileira:uma aplicação da análise de correlação canônica

This paper uses canonical correlation analisys to identify leading and coincident indicators of economic activity in Brazil. ln contrast with the traditional literature on the subject, no restrictions are made regarding the number of common cycles that are necessary to explain the complete cyclical behavior of the coincident variables. For the brazillian data, it is found that three common cycles exhaust all the cyclical pattern of economic activity. Based on the methodology developed here, it is also sugested an alternative chronology of the recent brazillian recessions.

Ensaios em econometria aplicada

This thesis has three chapters. Chapter 1 explores literature about exchange rate pass-through, approaching both empirical and theoretical issues. In Chapter 2, we formulate an estate space model for the estimation of the exchange rate pass-through of the Brazilian Real against the US Dollar, using monthly data from August 1999 to August 2008. The state space approach allows us to verify some empirical aspects presented by economic literature, such as coe cients inconstancy. The estimates o ffer evidence that the pass-through had variation over the observed sample. The state space approach is also used to test whether some of the "determinants" of pass-through are related to the exchange rate pass-through variations observed. According to our estimates, the variance of the exchange rate pass-through, monetary policy and trade ow have infuence on the exchange rate pass-through. The third and last chapter proposes the construction of a coincident and leading indicator of economic activity in the United States of America. These indicators are built using a probit state space model to incorporate the deliberations of the NBER Dating Cycles Committee regarding the state of the economy in the construction of the indexes. The estimates o ffer evidence that the NBER Committee weighs the coincident series (employees in nonagricultural payrolls, industrial production, personal income less transferences and sales) di fferently way over time and between recessions. We also had evidence that the number of employees in nonagricultural payrolls is the most important coincident series used by the NBER to de fine the periods of recession in the United States.

Essays in macroeconomy and dynamic term-structure models

This thesis is composed of three articles with the subjects of macroeconomics and - nance. Each article corresponds to a chapter and is done in paper format. In the rst article, which was done with Axel Simonsen, we model and estimate a small open economy for the Canadian economy in a two country General Equilibrium (DSGE) framework. We show that it is important to account for the correlation between Domestic and Foreign shocks and for the Incomplete Pass-Through. In the second chapter-paper, which was done with Hedibert Freitas Lopes, we estimate a Regime-switching Macro-Finance model for the term-structure of interest rates to study the US post-World War II (WWII) joint behavior of macro-variables and the yield-curve. We show that our model tracks well the US NBER cycles, the addition of changes of regime are important to explain the Expectation Theory of the term structure, and macro-variables have increasing importance in recessions to explain the variability of the yield curve. We also present a novel sequential Monte-Carlo algorithm to learn about the parameters and the latent states of the Economy. In the third chapter, I present a Gaussian A ne Term Structure Model (ATSM) with latent jumps in order to address two questions: (1) what are the implications of incorporating jumps in an ATSM for Asian option pricing, in the particular case of the Brazilian DI Index (IDI) option, and (2) how jumps and options a ect the bond risk-premia dynamics. I show that jump risk-premia is negative in a scenario of decreasing interest rates (my sample period) and is important to explain the level of yields, and that gaussian models without jumps and with constant intensity jumps are good to price Asian options.

Constructing coincident and leading indices of economic activity for the brazilian economy

This paper has three original contributions. The first is the reconstruction effort of the series of employment and income to allow the creation of a new coincident index for the Brazilian economic activity. The second is the construction of a coincident index of the economic activity for Brazil, and from it, (re)establish a chronology of recessions in the recent past of the Brazilian economy. The coincident index follows the methodology proposed by TCB and it covers the period 1980:1 to 2007:11. The third is the construction and evaluation of many leading indicators of economic activity for Brazil which fills an important gap in the Brazilian Business Cycles literature.

Tópicos em Econometria Aplicada

This paper has three original contributions. The first is the reconstruction of employment and income series to allow the creation of a new coincident index for the Brazilian economic activity. The second is the construction of a coincident index of the economic activity for Brazil, and from it, (re) establish a chronology of recessions in the recent past of the Brazilian economy. The coincident index follows the methodology proposed by The Conference Board and it covers the period 1980:1 to 2007:11. The third is the construction and evaluation of many leading indicators of economic activity for Brazil which fills an important gap in the Brazilian Business Cycles literature.

Constructing coincident and leading indices of economic activity for the brazilian economy

This paper has three original contributions. The first is the reconstruction effort of the series of employment and income to allow the creation of a new coincident index for the Brazilian economic activity. The second is the construction of a coincident index of the economic activity for Brazil, and from it, (re) establish a chronology of recessions in the recent past of the Brazilian economy. The coincident index follows the methodology proposed by The Conference Board (TCB) and it covers the period 1980:1 to 2007:11. The third is the construction and evaluation of many leading indicators of economic activity for Brazil which fills an important gap in the Brazilian Business Cycles literature.

Constructing coincident and leading indices of economic activity for the Brazilian economy

This paper has three original contributions. The fi rst is the reconstruction effort of the series of employment and income to allow the creation of a new coincident index for the Brazilian economic activity. The second is the construction of a coincident index of the economic activity for Brazil, and from it, (re) establish a chronology of recessions in the recent past of the Brazilian economy. The coincident index follows the methodology proposed by The Conference Board (TCB) and it covers the period 1980:1 to 2007:11. The third is the construction and evaluation of many leading indicators of economic activity for Brazil which fills an important gap in the Brazilian Business-Cycle literature.

Estimating Brazilian Monthly GDP: a State-Space Approach

This paper has several original contributions. The first is to employ a superior interpolation method that enables to estimate, nowcast and forecast monthly Brazilian GDP for 1980-2012 in an integrated way; see Bernanke, Gertler and Watson (1997, Brookings Papers on Economic Activity). Second, along the spirit of Mariano and Murasawa (2003, Journal of Applied Econometrics), we propose and test a myriad of interpolation models and interpolation auxiliary series- all coincident with GDP from a business-cycle dating point of view. Based on these results, we finally choose the most appropriate monthly indicator for Brazilian GDP. Third, this monthly GDP estimate is compared to an economic activity indicator widely used by practitioners in Brazil - the Brazilian Economic Activity Index - (IBC-Br). We found that the our monthly GDP tracks economic activity better than IBC-Br. This happens by construction, since our state-space approach imposes the restriction (discipline) that our monthly estimate must add up to the quarterly observed series in any given quarter, which may not hold regarding IBC-Br. Moreover, our method has the advantage to be easily implemented: it only requires conditioning on two observed series for estimation, while estimating IBC-Br requires the availability of hundreds of monthly series. Third, in a nowcasting and forecasting exercise, we illustrate the advantages of our integrated approach. Finally, we compare the chronology of recessions of our monthly estimate with those done elsewhere.

Growing research where economies grow: essays on strategy and international expansion of companies from emerging countries

In recent years, emerging countries have assumed an increasingly prominent position in the world economy, as growth has picked up in these countries and slowed in developed economies. Two related phenomena, among others, can be associated with this growth: emerging countries were less affected by the 2008-2009 global economic recession; and they increased their participation in foreign direct investment, both inflows and outflows. This doctoral dissertation contributes to research on firms from emerging countries through four independent papers. The first group of two papers examines firm strategy in recessionary moments and uses Brazil, one of the largest emerging countries, as setting for the investigation. Data were collected through a survey on Brazilian firms referring to the 2008-2009 global recession, and 17 hypotheses were tested using structural equation modeling based on partial least squares. Paper 1 offered an integrative model linking RBV to literatures on entrepreneurship, improvisation, and flexibility to indicate the characteristics and capabilities that allow a firm to have superior performance in recessions. We found that firms that pre-recession have a propensity to recognize opportunities and improvisation capabilities for fast and creative actions have superior performance in recessions. We also found that entrepreneurial orientation and flexibility have indirect effects. Paper 2 built on business cycle literature to study which strategies - pro-cyclical or counter-cyclical – enable superior performance in recessions. We found that while most firms pro-cyclically reduce costs and investments during recessions, a counter-cyclical strategy of investing in opportunities created by changes in the environment enables superior performance. Most successful are firms with a propensity to recognize opportunities, entrepreneurial orientation to invest, and flexibility to efficiently implement these investments. The second group of two papers investigated international expansion of multinational enterprises, particularly the use of distance for their location decisions. Paper 3 proposed a conceptual framework to examine circumstances under which distance is less important for international location decisions, taking the new perspective of economic institutional distance as theoretical foundation. The framework indicated that the general preference for low-distance countries is lower: (1) when the company is state owned, rather than private owned; (2) when its internationalization motives are asset, resource, or efficiency seeking, as opposed to market seeking; and (3) when internationalization occurred after globalization and the advent of new technologies. Paper 4 compared five concurrent perspectives of distance and indicated their suitability to the study of various issues based on industry, ownership, and type, motive, and timing of internationalization. The paper also proposed that distance represents the disadvantages of host countries for international location decisions; as such, it should be used in conjunction with factors that represent host country attractiveness, or advantages as international locations. In conjunction, papers 3 and 4 provided additional, alternative explanations for the mixed empirical results of current research on distance. Moreover, the studies shed light into the discussion of differences between multinational enterprises from emerging countries versus those from advanced countries.

Estimating brazilian monthly GDP: a state-space approach

This paper has several original contributions. The rst is to employ a superior interpolation method that enables to estimate, nowcast and forecast monthly Brazilian GDP for 1980-2012 in an integrated way; see Bernanke, Gertler and Watson (1997, Brookings Papers on Economic Activity). Second, along the spirit of Mariano and Murasawa (2003, Journal of Applied Econometrics), we propose and test a myriad of interpolation models and interpolation auxiliary series all coincident with GDP from a business-cycle dating point of view. Based on these results, we nally choose the most appropriate monthly indicator for Brazilian GDP. Third, this monthly GDP estimate is compared to an economic activity indicator widely used by practitioners in Brazil - the Brazilian Economic Activity Index - (IBC-Br). We found that the our monthly GDP tracks economic activity better than IBC-Br. This happens by construction, since our state-space approach imposes the restriction (discipline) that our monthly estimate must add up to the quarterly observed series in any given quarter, which may not hold regarding IBC-Br. Moreover, our method has the advantage to be easily implemented: it only requires conditioning on two observed series for estimation, while estimating IBC-Br requires the availability of hundreds of monthly series. Third, in a nowcasting and forecasting exercise, we illustrate the advantages of our integrated approach. Finally, we compare the chronology of recessions of our monthly estimate with those done elsewhere.

A monthly indicator of Brazilian GDP. The Brazilian business cycle and growth cycle

This paper constructs an indicator of Brazilian GDP at the monthly ftequency. The peculiar instability and abrupt changes of regimes in the dynamic behavior of the Brazilian business cycle were explicitly modeled within nonlinear ftameworks. In particular, a Markov switching dynarnic factor model was used to combine several macroeconomic variables that display simultaneous comovements with aggregate economic activity. The model generates as output a monthly indicator of the Brazilian GDP and real time probabilities of the current phase of the Brazilian business cycle. The monthly indicator shows a remarkable historical conformity with cyclical movements of GDP. In addition, the estimated filtered probabilities predict ali recessions in sample and out-of-sample. The ability of the indicator in linear forecasting growth rates of GDP is also examined. The estimated indicator displays a better in-sample and out-of-sample predictive performance in forecasting growth rates of real GDP, compared to a linear autoregressive model for GDP. These results suggest that the estimated monthly indicator can be used to forecast GDP and to monitor the state of the Brazilian economy in real time.

The impact of the 2008 economic recession on three residential property type investments: a case study of five diverse zip codes in Washington DC, USA

There has been 47 recessions in the United States of America (US) since 1790. US recessions have increasingly affected economies of other countries in the world as nations become more and more interdependent on each other. The worst economic recession so far was the “Great Depression” – an economic recession that was caused by the 1929 crash of the stock market in the US. The 2008 economic recession in the US was a result of the burst of the “housing bubble” created by predatory lending. The economic recession resulted in increased unemployment (according to NBER 8.7 million jobs were lost from Feb. 2008 to Feb. 2010); decrease in GDP by 5.1%; increase in poverty level from 12.1% (2007) to 16.0% (2008) (NBER) This dissertation is an attempt to research the impact of the 2008 economic recession on different types of residential investments: a case study of five (5) diverse neighborhoods/zip codes in Washington DC, USA The main findings were that the effect of the 2008 economic depression on the different types of residential properties was dependent on the location of the property and the demographics/socio-economic factors associated with that location.

Speed of adjustment of capital structure: empirical study

We analyze the impact of firm-specific characteristics as well as economic factors on the speed of adjustment to the target debt ratio. Using different methods, we document speeds of adjustment ranging from 14.4% to 37%. The results indicate that the speed of adjustment is affected by business-cycle variables: The interaction term related to term spread reveals, as expected, faster adjustment in booms than in recessions and a negative relationship between short term spread and adjustment speed. We also show that the speed of adjustment becomes stationary when the increasing fractions of zero-debt firms are considered.