Abstract types and distributions in independent private value auctions

In this note, in an independent private values auction framework, I discuss the relationship between the set of types and the distribution of types. I show that any set of types, finite dimensional or not, can be extended to a larger set of types preserving incentive compatibility constraints, expected revenue and bidder’s expected utilities. Thus for example we may convexify a set of types making our model amenable to the large body of theory in economics and mathematics that relies on convexity assumptions. An interesting application of this extension procedure is to show that although revenue equivalence is not valid in general if the set of types is not convex these mechanism have underlying distinct allocation mechanism in the extension. Thus we recover in these situations the revenue equivalence.

A Common-feature approach for testing present-value restrictions with financial data

It is well known that cointegration between the level of two variables (labeled Yt and yt in this paper) is a necessary condition to assess the empirical validity of a present-value model (PV and PVM, respectively, hereafter) linking them. The work on cointegration has been so prevalent that it is often overlooked that another necessary condition for the PVM to hold is that the forecast error entailed by the model is orthogonal to the past. The basis of this result is the use of rational expectations in forecasting future values of variables in the PVM. If this condition fails, the present-value equation will not be valid, since it will contain an additional term capturing the (non-zero) conditional expected value of future error terms. Our article has a few novel contributions, but two stand out. First, in testing for PVMs, we advise to split the restrictions implied by PV relationships into orthogonality conditions (or reduced rank restrictions) before additional tests on the value of parameters. We show that PV relationships entail a weak-form common feature relationship as in Hecq, Palm, and Urbain (2006) and in Athanasopoulos, Guillén, Issler and Vahid (2011) and also a polynomial serial-correlation common feature relationship as in Cubadda and Hecq (2001), which represent restrictions on dynamic models which allow several tests for the existence of PV relationships to be used. Because these relationships occur mostly with nancial data, we propose tests based on generalized method of moment (GMM) estimates, where it is straightforward to propose robust tests in the presence of heteroskedasticity. We also propose a robust Wald test developed to investigate the presence of reduced rank models. Their performance is evaluated in a Monte-Carlo exercise. Second, in the context of asset pricing, we propose applying a permanent-transitory (PT) decomposition based on Beveridge and Nelson (1981), which focus on extracting the long-run component of asset prices, a key concept in modern nancial theory as discussed in Alvarez and Jermann (2005), Hansen and Scheinkman (2009), and Nieuwerburgh, Lustig, Verdelhan (2010). Here again we can exploit the results developed in the common cycle literature to easily extract permament and transitory components under both long and also short-run restrictions. The techniques discussed herein are applied to long span annual data on long- and short-term interest rates and on price and dividend for the U.S. economy. In both applications we do not reject the existence of a common cyclical feature vector linking these two series. Extracting the long-run component shows the usefulness of our approach and highlights the presence of asset-pricing bubbles.

Forecasting multivariate time series under present-value-model short- and long-run co-movement restrictions

It is well known that cointegration between the level of two variables (e.g. prices and dividends) is a necessary condition to assess the empirical validity of a present-value model (PVM) linking them. The work on cointegration,namelyon long-run co-movements, has been so prevalent that it is often over-looked that another necessary condition for the PVM to hold is that the forecast error entailed by the model is orthogonal to the past. This amounts to investigate whether short-run co-movememts steming from common cyclical feature restrictions are also present in such a system. In this paper we test for the presence of such co-movement on long- and short-term interest rates and on price and dividend for the U.S. economy. We focuss on the potential improvement in forecasting accuracies when imposing those two types of restrictions coming from economic theory.

Insights on corporate sustainability and share value: an event study for Brazilian market

Em meio ao crescente volume de publicações sobre sustentabilidade e finanças, diversas pesquisas internacionais e brasileiras têm abordado a relação entre empresas classificadas como sustentáveis e o retorno de suas ações. Nesta mesma linha, este trabalho utilizou o método de estudos de eventos para verificar se entre 2005 e 2013 houve retornos anormais quando as empresas entraram e saíram do Índice de Sustentabilidade Empresarial (ISE). Além de contemplar um período mais atualizado do que seus precedentes, este estudo difere-se dos demais ao analisar o as observações individualmente e ao buscar estabelecer uma relação dos retornos anormais acumulados com as variáveis governança corporativa, tamanho, rentabilidade e alavancagem. Os resultados mostraram que embora não haja evidências conclusivas quando os casos são tomados individualmente, em conjunto eles indicam que a inclusão e a exclusão do ISE geram retornos anormais significativos, positivos e negativos respectivamente, em linha com a teoria dos stakeholders. Quanto às variáveis de controle, nenhuma apresentou relação com os retornos anormais acumulados.

Análise dos fundamentos do modelo value-based health care delivery à luz das teorias de estratégia

O setor de saúde, globalmente, apresenta problemas relacionados aos seus custos, qualidade e acesso. Porter e Teisberg (2004, 2006) propuseram modelo de gestão específico para a administração estratégica na área, o Value-Based Health Care Delivery (VBHCD). O modelo teve relativa repercussão e vem influenciando muitos atores no setor. Contudo, o modelo vem sendo aceito sem o devido questionamento de seus fundamentos e consistência com a teoria em estratégia. O presente trabalho busca, por meio de um ensaio teórico, analisar o modelo proposto à luz de paradigmas gerais da estratégia empresarial como, por exemplo, o modelo de Porter e a Visão Baseada em Recursos (RBV). Inicialmente, o artigo sintetiza as explicações teóricas do modelo porteriano clássico e da RBV. Em seguida, o VBHCD é examinado comparado a essas explicações, buscando-se relações e, eventualmente, contradições. Conclui-se que o modelo VBHCD não se alinha integralmente a nenhum corpo teórico isoladamente. Mesmo sendo proposto por Porter, parte de seus fundamentos advém, na verdade, de outras correntes teóricas. Esta abordagem integradora de teorias concorrentes, apesar de presente na literatura, ainda apresenta dificuldades e barreiras, um aspecto que não está explícito no modelo

The impact of negative social environmental events on the market value of supply chain partners

The present work analyzes the impact of negative social / environmental events on the market value of supply chain partners. The study offers a contextualized discussion around important concepts which are largely employed on the Operations Management and Management literature in general. Among them, the developments of the literature around supply chains, supply chain management, corporate social responsibility, sustainable development and sustainable supply chain management are particularly addressed, beyond the links they share with competitive advantage. As for the theoretical bases, the study rests on the Stakeholder Theory, on the discussion of the efficient-market hypothesis and on the discussion of the adjustment of stock prices to new information. In face of such literature review negative social / environmental events are then hypothesized as causing negative impact in the market value of supply chain partners. Through the documental analysis of publicly available information around 15 different cases (i.e. 15 events), 82 supply chain partners were identified. Event studies for seven different event windows were conducted on the variation of the stock price of each supply chain partner, valuing the market reaction to the stock price of a firm due to triggering events occurred in another. The results show that, in general, the market value of supply chain partners was not penalized in response to such announcements. In that sense, the hypothesis derived from the literature review is not confirmed. Beyond that, the study also provides a critical description of the 15 cases, identifying the companies that have originated such events and their supply chain partners involved.

A prisão sem muros da Queer Theory nos contos dama da noite e o rapaz mais triste do mundo de Caio Fernando Abreu

In this dissertation, we analyze, in a comparative perspective, the link between the short stories: Dama da Noite‟ and O Rapaz mais triste do mundo‟, of Caio Fernando Abreu. In order to reveal, analyze and establish relevant dialogues with Queer Theory, it‟s important, above all, make a misreading guided in the discursive contextuality of postmodern literature. In order to justify and clarify the many issues that arises in the emblematic relationships of characters that are present in the text and in the cultural context, historically and socially. It also highlights the utterance comparative value identified in the works, given the peculiarities of each one of them, not being possible to classify them as `figures of language` with which the comparison can be cited as an example. In this case, they serve to inspire the ways that may lead us to a better understanding of the parallels created between a world of the binary value and adjectives suggested by society and so well portrayed in the ideas and writings of Caio Fernando Abreu

Sharp bounds for the extreme zeros of classical orthogonal polynomials

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Generating Erler-Schnabl-type solution for the tachyon vacuum in cubic superstring field theory

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dressing approach to the nonvanishing boundary value problem for the AKNS hierarchy

We propose an approach to the nonvanishing boundary value problem for integrable hierarchies based on the dressing method. Then we apply the method to the AKNS hierarchy. The solutions are found by introducing appropriate vertex operators that takes into account the boundary conditions.

Towards a Realization of the Condensed-Matter-Gravity Correspondence in String Theory via Consistent Abelian Truncation of the Aharony-Bergman-Jafferis-Maldacena Model

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Non-stationary frequency analysis of extreme daily rainfall in São Paulo, Brazil

This work is an assessment of frequency of extreme values (EVs) of daily rainfall in the city of São Paulo. Brazil, over the period 1933-2005, based on the peaks-over-threshold (POT) and Generalized Pareto Distribution (GPD) approach. Usually. a GPD model is fitted to a sample of POT Values Selected With a constant threshold. However. in this work we use time-dependent thresholds, composed of relatively large p quantities (for example p of 0.97) of daily rainfall amounts computed from all available data. Samples of POT values were extracted with several Values of p. Four different GPD models (GPD-1, GPD-2, GPD-3. and GDP-4) were fitted to each one of these samples by the maximum likelihood (ML) method. The shape parameter was assumed constant for the four models, but time-varying covariates were incorporated into scale parameter of GPD-2. GPD-3, and GPD-4, describing annual cycle in GPD-2. linear trend in GPD-3, and both annual cycle and linear trend in GPD-4. The GPD-1 with constant scale and shape parameters is the simplest model. For identification of the best model among the four models WC used rescaled Akaike Information Criterion (AIC) with second-order bias correction. This criterion isolates GPD-3 as the best model, i.e. the one with positive linear trend in the scale parameter. The slope of this trend is significant compared to the null hypothesis of no trend, for about 98% confidence level. The non-parametric Mann-Kendall test also showed presence of positive trend in the annual frequency of excess over high thresholds. with p-value being virtually zero. Therefore. there is strong evidence that high quantiles of daily rainfall in the city of São Paulo have been increasing in magnitude and frequency over time. For example. 0.99 quantiles of daily rainfall amount have increased by about 40 mm between 1933 and 2005. Copyright (C) 2008 Royal Meteorological Society

A cooperative game theory analysis for transmission loss allocation

This paper presents an analysis and discussion, based on cooperative game theory, for the allocation of the cost of losses to generators and demands in transmission systems. We construct a cooperative game theory model in which the players are represented by equivalent bilateral exchanges and we search for a unique loss allocation solution, the Core. Other solution concepts, such as the Shapley Value, the Bilateral Shapley Value and the Kernel are also explored. Our main objective is to illustrate why is not possible to find an optimal solution for allocating the cost of losses to the users of a network. Results and relevant conclusions are presented for a 4-bus system and a 14-bus system. (c) 2007 Elsevier B.V. All rights reserved.

Correlation functions in super liouville theory

We calculate three- and four-point functions in super Liouville theory coupled to a super Coulomb gas on world sheets with spherical topology. We first integrate over the zero mode and assume that a parameter takes an integer value. We find the amplitudes, give plausibility arguments in favor of the result, and formally continue the parameter to an arbitrary real number. Remarkably the result is completely parallel to the bosonic case.