bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Nascent Galectin-1 Chimeric Molecule for Studying the Role of Leukocyte Galectin-1 Ligands and Immune Disease Modulation
Authors: Cedeno-Laurent Filiberto , Barthel Steven R. , Opperman Matthew J. , Lee David M. , Clark Rachael A. , Dimitroff Charles J.
Published: September 2010

Galectin-1 (Gal-1), a β-galactoside–binding lectin, plays a profound role in modulating adaptive immune responses by altering the phenotype and fate of T cells. Experimental data showing recombinant Gal-1 (rGal-1) efficacy on T cell viability and cytokine production, nevertheless, is controversial due to the necessity of using stabilizing chemicals to help retain Gal-1 structure and function. To address this drawback, we developed a mouse Gal-1 human Ig chimera (Gal-1hFc) that did not need chemical stabilization for Gal-1 ligand recognition, apoptosis induction, and cytokine modulation in a variety of leukocyte models. At high concentrations, Gal-1hFc induced apoptosis in Gal-1 ligand+ Th1 and Th17 cells, leukemic cells, and granulocytes from synovial fluids of patients with rheumatoid arthritis. Importantly, at low, more physiologic concentrations, Gal-1hFc retained its homodimeric form without losing functionality. Not only did Gal-1hFc–binding trigger IL-10 and Th2 cytokine expression in activated T cells, but members of the CD28 family and several other immunomodulatory molecules were upregulated. In a mouse model of contact hypersensitivity, we found that a non-Fc receptor-binding isoform of Gal-1hFc, Gal-1hFc2, alleviated T cell-dependent inflammation by increasing IL-4+, IL-10+, TGF-β+, and CD25high/FoxP3+ T cells, and by decreasing IFN-γ+ and IL-17+ T cells. Moreover, in human skin-resident T cell cultures, Gal-1hFc diminished IL-17+ T cells and increased IL-4+ and IL-10+ T cells. Gal-1hFc will not only be a useful new tool for investigating the role of Gal-1 ligands in leukocyte death and cytokine stimulation, but for studying how Gal-1–Gal-1 ligand binding shapes the intensity of immune responses.
IL-21 Deficiency Influences CD8 T Cell Quality and Recall Responses following an Acute Viral Infection
Authors: Yi John S. , Ingram Jennifer T. , Zajac Allan J.
Published: September 2010

CD4 T cells are principal producers of IL-21 and are often required for optimal CD8 T cell responses. Therefore, we investigated the importance of IL-21 in determining the phenotypic attributes, functional quality, and maintenance of antiviral CD8 T cells following acute infection with the prototypic mouse pathogen lymphocytic choriomeningitis virus. Previous reports have documented an obligatory role for IL-21 in sustaining CD8 T cell responses during chronic infections. Here we show that the requirements for IL-21 are less stringent following acute infections; however, in the absence of IL-21, the capacity of CD8 T cells to attain the polyfunctional trait of IL-2 production is consistently reduced during both the effector and memory phases. This is further supported by in vitro studies showing that the addition of IL-21 promotes the differentiation of IL-2–producing CD8 T cells. Although the generation of memory CD8 T cells, which are capable of mounting protective recall responses, proceeds independently of IL-21, we demonstrate that IL-21 does function to support secondary responses, especially under competitive conditions. Collectively, these studies highlight the potential roles of IL-21 in determining the quality of CD8 T cell responses postinfection.
Thrombospondin-1 Derived from APCs Regulates Their Capacity for Allosensitization
Authors: Saban Daniel R. , Bock Felix , Chauhan Sunil K. , Masli Sharmila , Dana Reza
Published: September 2010

Thrombospondin (TSP)-1 is a matricellular glycoprotein with immunoregulatory properties, which include inhibition of APC function. We show in transplantation that TSP-1 inhibits T cell allosensitization and consequently suppresses immune rejection. This was revealed by comparing wild-type (WT) versus TSP-1 null allografts in corneal transplantation, as the cornea is a rich source of TSP-1. Compared with only 50% of rejected WT allografts, nearly all TSP-1 null allografts succumbed to rejection. This effect was reflected by donor-derived APCs, which exhibited a distinctively greater capacity for allosensitization in transplanted hosts. Corroborated in MLRs, greater proliferation levels and robust IFN-γ (but not IL-10)–positive T cells resulted from stimulation by TSP-1 null APCs relative to WT ones. Moreover, enhanced expression of MHC class II and B7 maturation markers were detected on TSP-1 null APCs during inflammation. Increased expression of CCR7 was further matched by enhanced lymph node migration of TSP-1 null APCs posttransplantation. We therefore conclude that APC-derived TSP-1 suppresses their capacity to allosensitize T cells, and this regulation stems from their resistance to taking on a mature form. Future strategies targeting APCs for TSP-1 upregulation may thus be effective in promoting allograft survival.
Lunatic Fringe Enhances Competition for Delta-Like Notch Ligands but Does Not Overcome Defective Pre-TCR Signaling during Thymocyte β-Selection In Vivo
Authors: Visan Ioana , Yuan Julie S. , Liu Ying , Stanley Pamela , Guidos Cynthia J.
Published: September 2010

Notch1 activation by Delta-like (DL) Notch ligands is essential to induce T cell commitment and to suppress B cell development from thymus-seeding progenitors. Thymus-seeding progenitor competition for DL4 is critically regulated by Lunatic Fringe (Lfng), which glycosylates epidermal growth factor repeats in the Notch1 extracellular domain to enhance binding avidity for DL ligands. Notch1 activation is also essential for the process of β-selection, which drives TCRβ+ CD4/CD8 double-negative 3 (DN3) precursors to proliferate and generate a large pool of CD4/CD8 double-positive thymocytes. We have used several genetic approaches to determine the importance of Lfng–Notch1 interactions in regulating competition of preselection and postselection DN3 thymocytes for DL ligands in vivo. Surprisingly, although Lfng overexpression enhanced DL4 binding by preselection DN3a thymocytes, it did not confer them with a competitive advantage in mixed chimeras. In contrast, Lfng overexpression enhanced competition of post–β-selection DN3b precursors for DL ligands. Lfng modification of O-fucose in the Notch1 ligand-binding domain contributed to but was not solely responsible for the developmental effects of Lfng overexpression. Although previous studies have suggested that pre–TCR-deficient DN3 thymocytes compete poorly for DL ligands, Lfng overexpression did not fully restore double-positive thymocyte pools from DN3b cells with pre-TCR signaling defects. Thus, pre-TCR and Notch signaling have largely nonoverlapping functions in β-selection. Collectively, our data reveal that Lfng enhances DN3b precursor competition for intrathymic DL ligands to maximize Notch-induced clonal expansion during the earliest stage of β-selection.
TLR Agonists That Induce IFN-β Abrogate Resident Macrophage Suppression of T Cells
Authors: Hamilton Melisa J. , Antignano Frann , von Rossum Anna , Boucher Jean-Luc , Bennewith Kevin L. , Krystal Gerald
Published: September 2010

Resident tissue macrophages (Mϕs) continually survey the microenvironment, ingesting Ags and presenting them on their surface for recognition by T cells. Because these Ags can be either host cell- or pathogen-derived, Mϕs must be able to distinguish whether a particular Ag should provoke an immune response or be tolerated. However, the mechanisms that determine whether Mϕs promote or inhibit T cell activation are not well understood. To investigate this, we first determined the mechanism by which murine resident peritoneal Mϕs suppress in vitro T cell proliferation in the absence of pathogens and then explored the effects of different pathogen-derived molecules on Mϕ immunosuppression. Our results suggest that, in response to IFN-γ, which is secreted by TCR-activated T cells, resident peritoneal Mϕs acquire immunosuppressive properties that are mediated by NO. However, pretreatment of Mϕs with LPS or dsRNA, but not CpG or peptidoglycan, eliminates their suppressive properties, in part via the induction of autocrine-acting IFN-β. These results suggest TLR agonists that activate TRIF, and consequently induce IFN-β, but not those that exclusively signal through MyD88, abrogate the immunosuppressive properties of Mϕs, and thus promote T cell expansion and elimination of invading microorganisms.
LATERAL SINUS THROMBOSIS IN OTOLOGY: A REVIEW
Authors: Visavanatha B , Naseeruddin Khaja
Published: September 2010

Lateral sinus thrombosis (LST) is usually occurs as a complication of middle ear infection .The involvement of lateral sinus during the course of ear infection was a well known complication in preantibiotic days .The decrease in the incidence of LST is due to the introduction of broad-spectrum antibiotics, early diagnosis and surgical treatment. Now, it is a rare complication of otitis media and poses a serious threat that warrants immediate medical and surgical treatment. The classical clinical picture is often changed by previous antibiotic therapy. An awareness of this rare potentially devastating condition and its varied presentations is necessary for early diagnosis and treatment. LST can also occur after head injury.
Numerical Resolution Near t = 0 of Nonlinear Evolution Equations in the Presence of Corner Singularities in Space Dimension 1
Authors: Chen Qingshan , Qin Zhen , Temam Roger
Published: September 2010

The incompatibilities between the initial and boundary data will cause singularities at the time-space corners, which in turn adversely affect the accuracy of the numerical schemes used to compute the solutions. We study the corner singularity issue for nonlinear evolution equations in 1D, and propose two remedy procedures that effectively recover much of the accuracy of the numerical scheme in use. Applications of the remedy procedures to the 1D viscous Burgers equation, and to the 1D nonlinear reaction-diffusion equation are presented. The remedy procedures are applicable to other nonlinear diffusion equations as well.
Variance-Based Global Sensitivity Analysis via Sparse-Grid Interpolation and Cubature
Authors: Buzzard Gregery T. , Xiu Dongbin
Published: September 2010

The stochastic collocation method using sparse grids has become a popular choice for performing stochastic computations in high dimensional (random) parameter space. In addition to providing highly accurate stochastic solutions, the sparse grid collocation results naturally contain sensitivity information with respect to the input random parameters. In this paper, we use the sparse grid interpolation and cubature methods of Smolyak together with combinatorial analysis to give a computationally efficient method for computing the global sensitivity values of Sobol’. This method allows for approximation of all main effect and total effect values from evaluation of f on a single set of sparse grids. We discuss convergence of this method, apply it to several test cases and compare to existing methods. As a result which may be of independent interest, we recover an explicit formula for evaluating a Lagrange basis interpolating polynomial associated with the Chebyshev extrema. This allows one to manipulate the sparse grid collocation results in a highly efficient manner.
A Review of David Gottlieb’s Work on the Resolution of the Gibbs Phenomenon
Authors: Gottlieb Sigal , Jung Jae-Hun , Kim Saeja
Published: September 2010

Given a piecewise smooth function, it is possible to construct a global expansion in some complete orthogonal basis, such as the Fourier basis. However, the local discontinuities of the function will destroy the convergence of global approximations, even in regions for which the underlying function is analytic. The global expansions are contaminated by the presence of a local discontinuity, and the result is that the partial sums are oscillatory and feature non-uniform convergence. This characteristic behavior is called the Gibbs phenomenon. However, David Gottlieb and Chi-Wang Shu showed that these slowly and non-uniformly convergent global approximations retain within them high order information which can be recovered with suitable postprocessing. In this paper we review the history of the Gibbs phenomenon and the story of its resolution.
Learning Causal Relations in Multivariate Time Series Data
Authors: Chen Pu , Chihying Hsiao
Published: September 2010

Applying a probabilistic causal approach, we define a class of time series causal models (TSCM) based on stationary Bayesian networks. A TSCM can be seen as a structural VAR identified by the causal relations among the variables. We classify TSCMs into observationally equivalent classes by providing a necessary and sufficient condition for the observational equivalence. Applying an automated learning algorithm, we are able to consistently identify the data-generating causal structure up to the class of observational equivalence. In this way we can characterize the empirical testable causal orders among variables based on their observed time series data. It is shown that while an unconstrained VAR model does not imply any causal orders in the variables, a TSCM that contains some empirically testable causal orders implies a restricted SVAR model. We also discuss the relation between the probabilistic causal concept presented in TSCMs and the concept of Granger causality. It is demonstrated in an application example that this methodology can be used to construct structural equations with causal interpretations.
Testing for Breaks in Cointegrated Panels − with an Application to the Feldstein-Horioka Puzzle
Authors: Di Iorio Francesca , Fachin Stefano
Published: September 2010

Stability tests for cointegrating coefficients are known to have very low power with small to medium sample sizes. In this paper we propose to solve this problem by extending the tests to dependent cointegrated panels through the stationary bootstrap. Simulation evidence shows that the proposed panel tests improve considerably on asymptotic tests applied to individual series. As an empirical illustration we examined investment and saving for a panel of European countries over the 1960-2002 period. While the individual stability tests, contrary to expectations and graphical evidence, in almost all cases do not reject the null of stability, the bootstrap panel tests lead to the more plausible conclusion that the long-run relationship between these two variables is likely to have undergone a break.
An Idealized View of Financial Intermediation
Authors: Sissoko Carolyn
Published: September 2010

We consider an environment where the general equilibrium assumption that every agent buys and sells simultaneously is relaxed. We show that fiat money can implement a Pareto optimal allocation only if taxes are type-specific. We then consider intermediated money by assuming that financial intermediaries whose liabilities circulate as money have an important identifying characteristic: they are widely viewed as default-free. The paper demonstrates that default-free intermediaries who issue deposit accounts with credit lines to consumers can resolve the monetary problem and make it possible for the economy to reach a Pareto optimum.
Hidden Economies and the Socially Optimal Fiscal-Tax to Liquidity-Tax Ratio
Authors: Ercolani Marco G.
Published: September 2010

Differential tax analysis is used to show how the socially optimal fiscal-tax to liquidity-tax ratio changes with the relative size of the tax-evading hidden economy. The smaller the relative size of the hidden economy, the larger the optimal fiscal-tax to liquidity-tax ratio. The empirical cross-section and panel evidence supports this theoretical result.
Shadow Economies and Corruption All Over the World: Revised Estimates for 120 Countries
Authors: Schneider Friedrich , Buehn Andreas
Published: September 2010

Estimations of the shadow economies for 120 countries, including developing, Eastern Europe and Central Asian and high income OECD countries over 1999 to 2006 are presented. The average size of the shadow economy (as a percent of “official” GDP) in 2004/05 in 76 developing countries is 35.5%, in 19 Eastern and Central Asian countries 36.7% and in 25 high income OECD countries 15.5%. An increased burden of taxation and social security contributions, combined with labour market regulations are the driving forces of the shadow economy. Furthermore, the results show that the shadow economy reduces corruption in high income countries, but increases corruption in low income countries. Finally, the various estimation methods are discussed and critically evaluated.
Production Constraints and the NAIRU
Authors: Driver Ciaran , Hall Stephen G.
Published: September 2010

This paper argues that the production constraints in the basic NAIRU model should be distinguished by type: capital constraints and labour constraints. It notes the failure to incorporate this phenomenon in standard macro models. Using panel data for UK manufacturing over 80 quarters we show that capital constraints became relatively more important during the 1980s as industry failed to match the increase in labour flexibility with rising capital investment.
The Single Currency’s Effects on Eurozone Sectoral Trade: Winners and Losers?
Authors: de Nardis Sergio , De Santis Roberta , Vicarelli Claudio
Published: September 2010

In this paper we study the effect of the single currency across industries for euro area members. This analysis may help to shed light on the main factors influencing the euro effect on trade flows. We intend to verify whether these factors are specific to individual sectors and/or countries or common to the entire euro area. We use a dynamic specification of an augmented gravity equation. Following the most recent econometric literature, we apply the “System GMM” dynamic panel data estimator of Blundell and Bond to avoid inconsistency and biases in the estimates, and introduce controls for heterogeneity.

Aggregate sector results average out country-level behaviours that, on their turn, are affected by different (unobserved) responses of firms, endowed with diverse production costs, to the enhancing and dampening impacts due to the euro. Due to this reason, the cancelling out at aggregate level of heterogenous behaviours induces an aggregation bias. So it is not surprising that when moving from sector to sector/country analysis the picture becomes much more variegated, with the emergence of a whole range of winners and losers among industries in the different nation.

Our empirical results are in line with theoretical framework we assumed as reference that considers the possibility of both stimulative and dampening effects coming from trade integration and points out the fact that sector exports impacts are the aggregation results of firm-level heterogenous behaviours.
The Demand for Currency Substitution
Authors: Seater John J.
Published: September 2010

A transactions model of the demand for multiple media of exchange is developed. Some results are expected, and others are both new and surprising. There are both extensive and intensive margins to currency substitution, and inflation may affect the two margins differently, leading to subtle incentives to adopt or abandon a substitute currency. Variables not previously considered in the literature affect currency substitution in complex and somewhat unexpected ways. In particular, the level of income and the composition of consumption expenditures are important, and they interact with the other variables in the model. Independent empirical work provides support for the theory.
Welfare Effects of Intellectual Property in a North-South Model of Endogenous Growth with Comparative Advantage
Authors: Saint-Paul Gilles
Published: September 2010

This paper develops a model for analyzing the costs and benefits of intellectual property enforcement in LDCs. The North is more productive than the South and is the only source of innovator. There are two types of goods, and each bloc has a comparative advantage in producing a specific type of good. If comparative advantage is strong enough, even under piracy there are goods that the South will not produce. Piracy will then lead to a reallocation of innovative activity in favor of these goods. That may harm consumers (including consumers in the South) to the extent that these goods have smaller dynamic learning externalities than the other goods, and that their share in consumption is small. Thus, whether or not piracy is in the interest of the South depends on how important are the goods for which it has a comparative advantage to its consumers, and what the growth potential of these goods is. While, all else equal, the North tends to lose more (or gain less) from piracy than the South, because monopoly profits eventually accrue to the North, the South may lose more than the North if there is a strong enough home bias in favor of the goods for which it has a comparative advantage.
The New Growth Theories and Their Empirics after Twenty Years
Authors: Capolupo Rosa
Published: September 2010

In this work the author updates the reviews on endogenous growth theories in order to explore whether recent empirical studies have become more supportive of their main predictions. Among the core topics studied in the growth econometric framework, namely convergence, identification of growth determinants and factors responsible for growth differences in the data, the primary focus of this paper is on the last two. The author will review, from macro growth regressions, studies that test primarily the performance of endogenous models in terms of significance and robustness of the coefficients of growth determinants. By highlighting methodological issues and critical discussion, she argues that: (i) causal inference drawn from the empirical growth literature remains highly questionable, (ii) there are estimates for a wide range of potential factors but their magnitude and robustness are still under debate. Her conclusion, however, is that, if properly interpreted, the predictions of endogenous growth models are gathering increasing empirical support.
The Pre-Eminence of Theory versus the European CVAR Perspective in Macroeconometric Modeling
Authors: Spanos Aris
Published: September 2010

The primary aim of the paper is to place current methodological discussions in macroeconometric modeling contrasting the ‘theory first’ versus the ‘data first’ perspectives in the context of a broader methodological framework with a view to constructively appraise them. In particular, the paper focuses on Colander’s argument in his paper “Economists, Incentives, Judgement, and the European CVAR Approach to Macroeconometrics” contrasting two different perspectives in Europe and the US that are currently dominating empirical macroeconometric modeling and delves deeper into their methodological/philosophical underpinnings. It is argued that the key to establishing a constructive dialogue between them is provided by a better understanding of the role of data in modern statistical inference, and how that relates to the centuries old issue of the realisticness of economic theories.
DSGE Models and Central Banks
Authors: Tovar Camilo E.
Published: September 2010

Over the past 15 years there has been remarkable progress in the specification and estimation of dynamic stochastic general equilibrium (DSGE) models. Central banks in developed and emerging market economies have become increasingly interested in their usefulness for policy analysis and forecasting. This paper reviews some issues and challenges surrounding the use of these models at central banks. It recognises that they offer coherent frameworks for structuring policy discussions. Nonetheless, they are not ready to accomplish all that is being asked of them. First, they still need to incorporate relevant transmission mechanisms or sectors of the economy; second, issues remain on how to empirically validate them; and finally, challenges remain on how to effectively communicate their features and implications to policy makers and to the public. Overall, at their current stage DSGE models have important limitations. How much of a problem this is will depend on their specific use at central banks.
The Balassa–Samuelson Hypothesis in Developed Countries and Emerging Market Economies: Different Outcomes Explained
Authors: García-Solanes José , Torrejón-Flores Fernando
Published: September 2010

This paper studies the Balassa–Samuelson effects in two areas with strong differences in economic development, sixteen OECD countries and sixteen Latin American economies. The USA is taken as a benchmark. Applying recent panel cointegration and bootstrapping techniques that solve for cross-sectional dependence and small panel size problems, we find some evidence for not rejecting the whole hypothesis in the LA area. In the context of OECD group, the second stage of the BS hypothesis, which relates relative sector prices with the real exchange rate, does not hold, probably because national markets remain to some extent segmented, as reflected in departures from PPP in the tradable sectors.
Climate Policy Options and the World Trade Organization
Authors: Hufbauer Gary Clyde , Kim Jisun
Published: September 2010

This paper examines whether the climate policy options policymakers are contemplating are compatible with core principles of the world trading system set forth in the General Agreement on Tariffs and Trade (GATT), the World Trade Organization (WTO), and Appellate Body decisions. The authors argue that border measures—both import restrictive measures and export subsidies—contemplated in US climate bills and the climate policies of other countries stand a fair chance of being challenged in the WTO. Given the prospect of foreseeable conflicts with WTO rules, the authors suggest that key WTO members should attempt to negotiate a new code that delineates a large “green space” for measures that are designed to limit GHG emissions both within the member country and globally. By “green space,” the authors mean policy space for climate measures that are imposed in a manner broadly consistent with core WTO principles even if a technical violation of WTO law could occur. To encourage WTO negotiating efforts along these lines, the authors recommend a time-limited “peace clause” to be adopted into climate legislation of major emitting countries. The peace clause would suspend the application of border measures or other extraterritorial controls for a defined period while WTO negotiations are under way.

Published as Policy Paper
Social Policy Targeting and Binary Information Transfer between Surveys
Authors: Gottlieb Daniel , Kushnir Leonid
Published: September 2010

In this paper we develop a methodology for identifying a population group surveyed latently in the (target) survey relevant for further processing, for example poverty calculations, but surveyed explicitly in another (source) survey, not suitable for such processing. Identification is achieved by transferring the binary information from the source survey to the target survey by means of a logistic regression determining group affiliation in the source survey by use of variables available also in the target survey. In the proposed methodology we improve on common matching procedures by optimizing the cut-value of the probability which assigns group affiliation in the target survey. This contrasts with the commonly used “Hosmer-Lemeshov” cut-values for binary categorization, which equates between the sensitivity and specificity curves. Instead we improve group identification by minimizing the sum of total errors as a percent of total true outcomes.

The Jewish ultra-orthodox population in Israel serves as a case study. This idiosyncratic community, committed to the observance of the Bible is only latently observed in the surveys typically used for poverty calculation. It is explicitly captured in the social survey, which is not suitable for poverty measurement.

This procedure is useful for ex-post enhancement of survey data in general.
Network Structure of Japanese Firms. Scale-Free, Hierarchy, and Degree Correlation: Analysis from 800,000 Firms
Authors: Konno Tomohiko
Published: September 2010

We analyze fundamental characteristics of the inter-firm transaction network through the data of 800,000 Japanese firms. We find that there exists a hierarchical structure and a negative degree correlation in this transaction network. We also find that this undirected network is a scale-free network. We bring to light these characteristics of the network and discuss why there is an important need to conduct research work on the actual network structure.
Heterogeneous Parameter Uncertainty and the Timing of Investment during Crisis
Authors: Ni Shawn , Ratti Ronald A.
Published: September 2010

We present a model in which investors observe the same macroeconomic data but have varying levels of information about the parameters that determine the distribution of the expected returns on investment. During a crisis that increases macroeconomic uncertainty and reduces asset prices, the threshold required return that triggers investment is lower for an informed investor than for an uninformed investor. Simulation of the model suggests that when macroeconomic uncertainty is high investment may increase, is mostly by informed investors, and as time goes on is progressively more by investors who were initially relatively uninformed about model parameters. For over 10,000 instances of firm-level FDI data for Korea from 1996 to 2001, regression results are consistent with the hypothesis that disproportionably more FDI is made by more informed investors during a period of high macroeconomic uncertainty.
Occupational Upgrading and the Business Cycle in West Germany
Authors: Büttner Thomas , Jacobebbinghaus Peter , Ludsteck Johannes
Published: September 2010

The occupational skill structure depends on the business cycle if employers respond to shortages of applicants during upturns by lowering their hiring standards. Devereux uses this implication to construct empirical tests for the notion of hiring standards adjustment (the so-called Reder hypothesis) and finds affirmative evidence for the U.S labour market. The authors replicate his analysis using German employment register data. Regarding the occupational skill composition they obtain somewhat lower but qualitatively similar responses to the business cycle despite of well known institutional differences between the U.S. and German labour market. The responsiveness of occupational composition wages to the business cycle is considerably lower in Germany.
Housing Wealth Isn’t Wealth
Authors: Buiter Willem H.
Published: September 2010

A fall in house prices due to a change in fundamental value redistributes wealth from those long housing (for whom the fundamental value of the house they own exceeds the present discounted value of their planned future consumption of housing services) to those short housing. In a closed economy representative agent model (the special case when the birth rate is zero, of the Yaari-Blanchard OLG model used in the paper), there is no pure wealth effect on consumption from a change in house prices if this represents a change in their fundamental value. When the birth rate is positive, higher fundamental house prices driven by the housing demand of future generations will boost current consumption.

There is a pure wealth effect on consumption from a change in house prices even in the representative agent model, if this reflects a change in the speculative bubble component of house prices.

Two other channels through which a fall in house prices can affect aggregate consumption are (1) redistribution effects if the marginal propensity to spend out of wealth differs between those long housing (the old, say) and those short housing (the young, say) and (2) collateral or credit effects due to the collateralisability of housing wealth and the non-collateralisability of human wealth. A decline in house prices reduces the scope for mortgage equity withdrawal. For given sequences of future after-tax labour income and interest rates, a fall in house prices will then depress consumption in the short run while boosting it in the long run.
The Crisis and Beyond: Thinking Outside the Box
Authors: Hillinger Claude
Published: September 2010

In this paper the author attempts an analysis of the current financial/economic crisis that is wider ranging and more fundamental than he has been able to find. He discusses alternatives to the financial bailouts and shows how the crisis could have been dealt with more efficiently and at little cost to taxpayers. Finally, the author discusses fundamental reforms that would reduce the volatility of financial markets and increase their efficiency. He reviews some social science literature that views the current crisis as an episode in the secular decline of the United States and more generally of the Western Democracies. The timidity of current reforms, which is striking when compared to those that followed the excesses of the Gilded Age and the Great Depression, can be understood in this framework. The author concludes that the industrialized world is now dominated by a ‘financial-political complex’ that maximizes speculative profits in good times and socializes losses in times of crisis.
A Tale of Two Debt Crises: A Stochastic Optimal Control Analysis
Authors: Stein Jerome L.
Published: September 2010

Creditors, banks and bank regulators should evaluate whether a borrower is likely to default. I apply several techniques in the extensive mathematical literature of stochastic optimal control/dynamic programming to derive an optimal debt in an environment where there are risks on both the asset and liabilities sides. The vulnerability of the borrowing firm to shocks from either the return to capital, the interest rate or capital gain, increases in proportion to the difference between the Actual and Optimal debt ratio, called the excess debt. As the debt ratio exceeds the optimum, default becomes ever more likely. This paper is “A Tale of Two Crises” because the same analysis is applied to the agricultural debt crisis of the 1980s and to the subprime mortgage crisis of 2007. A measure of excess debt is derived, and we show that it is an early warning signal of a crisis in both cases.
Selection Wages and Discrimination
Authors: Schlicht Ekkehart
Published: September 2010

Applicants for any given job are more or less suited to fill it, and the firm will select the best among them. Increasing the wage offer attracts more applicants and makes it possible to raise the hiring standard, thereby improving the productivity of the staff. Wages that optimize on the trade-off between the wage level and the productivity of the workforce are known as selection wages. As men react more strongly to wage differentials than females, the trade-off is more pronounced for men and a profit-maximizing firm will offer a higher wage for men than for women in equilibrium. The argument is not confined to issues of sex discrimination; rather it is of relevance for all labor markets where labor heterogeneity is important and supply elasticities vary systematically across occupations.
Disclosure Requirements, the Release of New Information and Market Efficiency: New Insights from Agent-based Models
Authors: Hermsen Oliver , Witte Björn-Christopher , Westerhoff Frank
Published: September 2010

We explore how disclosure requirements that regulate the release of new information may affect the dynamics of financial markets. Our analysis is based on three agent-based financial market models that are able to produce realistic financial market dynamics. We discover that the average deviation between market prices and fundamental values increases if new information is released with a delay, while the average price volatility is virtually unaffected by such regulations. Interestingly, the tails of the distribution of returns become fatter if fundamental data is released less continuously, indicating an increase in financial market risk.
Transaction Taxes and Traders with Heterogeneous Investment Horizons in an Agent-Based Financial Market Model
Authors: Demary Markus
Published: September 2010

This agent-based financial market model is a generalization of the model of Westerhoff (The Use of Agent-Based Financial Market Models to Test the Effectiveness of Regulatory Policies) by traders who are allowed to have different investment horizons as introduced by Demary (Who Does a Currency Transaction Tax Harm More: Short-Term Speculators or Long-Term Investors?). Our research goals are, first, to study what consequences the introduction of heterogeneous investment horizons has for agent-based financial market models, and second, how effective transaction taxes are in stabilizing financial markets. Numerical simulations reveal that under sufficiently small tax rates traders abstain from short-term trading in favour of longer investment horizons. This change in behavior leads to less volatility and less mispricings. When the tax rate exceeds a certain threshold, however, mispricings increase as also found in Westerhoff (Heterogeneous Traders and the Tobin Tax and The Use of Agent-Based Financial Market Models to Test the Effectiveness of Regulatory Policies). This emergent property is due to the fact that taxation reduces short-term fluctuations and causes longer lasting trends in the exchange rate. As a result, the longer term fundamentalist trading rule becomes unpopular in favor of the longer term trend-chasing rule.
Lethal and Sub-Lethal Effects of the Water-Soluble Fraction of a Light Crude Oil on the Planktonic Copepod Acartia tonsa
Authors: Avila T. R. , Bersano J. G. F. , Fillmann G.
Published: September 2010

In this study the acute and sub-lethal effects caused by the Water Soluble Fraction (WSF) of a light crude oil were assessed for the first time on the planktonic copepod Acartia tonsa. Chromatographic analysis was also performed to quantify the levels of hydrocarbons (total, aliphatic and polyaromatic hydrocarbons) to which copepods were exposed to. Male and female individuals were exposed to hydrocarbon concentrations varying from 12 to 196 μg.L–1 (Total hydrocarbons). The LC50 was 69.5 (24 hours) and 48.0 μg.L–1 (48 hours) for females and 84.8 (24 hours) and 70.1 μg.L–1 (48 hours) for males. Sub-lethal effects were also evaluated by exposing females to the equivalent of LC10. Females showed significant reduction in egg and fecal pellet production, and also a delay in the eggs hatching time. Thus, the toxic effects of WSF of oil may be crucial for the specie population maintenance, possibly influencing the equilibrium of marine ecosystems.
Aerobic Reactors for Biotreatment of Polluted Waters and Synthetic Effluents Containing 3-Chlorobenzoic Acid
Authors: Gallego A. , Rossen A. , Gemini V. , Fortunato M. S. , Rossi S. , Planes E. , Korol S.
Published: September 2010

The degradation of 3-chlorobenzoic acid in polluted waters and synthetic effluents by a previously isolated indigenous strain of Pseudomonas putida was studied. Batch biodegradation assays were performed using a 2 L microfermentor at 28 °C with agitation. To simulate polluted water, 100 mg.L–1 of 3-chlorobenzoic acid were added to surface river water. Continuous-flow assays were performed in an aerobic up-flow fixed-bed reactor constructed from PVC employing hollow PVC cylinders as support material. Synthetic wastewater was prepared by dissolving 3-chlorobenzoic acid in non-sterile groundwater. Biodegradation was evaluated by spectrophotometry, chloride release, gas chromatography and microbial growth. In batch experiments the indigenous strain of Pseudomonas putida degrades 100 mg.L–1 of 3-chlorobenzoic acid in 28 hours with a removal efficiency of 92.2 and 87.2%, expressed as compound and chemical oxygen demand removal, respectively. In the continuous-flow reactor the removal of an average influent concentration of 98.6 mg.L–1 reached 91.7% of compound and 88.9% of COD removal. The process efficiency remained approximately constant despite changes in the influent flow, compound concentration and temperature. The absence of metabolites was determined by gas chromatography performed at the end of the batch process and at the effluent of the continuous reactor. The ability of the isolated indigenous strain to degrade 3-chlorobenzoic acid in both batch and continuous reactors represents a promising feature to improve the treatment of effluents.
Total Mercury Distribution in Muscular Tissue of Hypostomus affinis (Steindachner, 1877) and Hypostomus c.f. luetkini (Barlenger, 1887) from Muriaé River, Itaperuna – RJ
Authors: Araujo B. F. , Carvalho C. E. V. , Andrade D. R. , Gomes R. S. , Souza C. T.
Published: September 2010

With the purpose of evaluating the consumed fish quality, total mercury concentration were analyzed in muscle samples from two tropical freshwater fish (Hypostomus affinis Steindachner,1877 and Hypostomus c.f. luetkini, Barlenger,1887) from the Muriaé River, Itaperuna Municipality, in the North of Rio de Janeiro State. A secondary objective of the present study was to compare mercury concentration in these two species during dry and wet seasons. In order to achieve these goals, five organisms from each species were monthly collected between August 2005 and January 2006. H. affinis always presented lower total mercury average concentration when compared with H. c.f. luetkini with exception of August 2005 when an opposite trend was observed. The highest mercury concentrations were observed in October for both species (H. affinis 33.4 ng.g–1 in wet weight and H. c.f. luetkini 39.5 ng.g–1 in wet weight) during the beginning of dry season. There was a clear trend of higher Hg concentrations during the dry season when compared to the wet season probably related with the dilution effect caused by the increasing water discharges during the wet season. All analyzed samples presented total mercury concentrations lower than the maximum permitted concentration for human consumption established by ANVISA and WHO (500 ng.g–1 in wet weight), therefore no risk for human consumption was observed.
Exploratory Analysis of the Incidence of Nitro-Naphthalenes in the of Airborne Particulate Matter from Petrochemical Influence Area
Authors: Apel M. A. , Rocha J. A. V. , Coronas M. V. , Vargas V. M. F.
Published: September 2010

Airborne­ particulate­ matter­ samples­ collected­ in­ sites­ under­ petrochemical­ influence,­ in­ Triunfo­ city­ –­ Rio­ Grande­ do­ Sul,­ Brazil,­ were­ analyzed ­by ­GC/MS-SIM­ for ­nitro-naphthalenes.­ Total­ Suspended­ Particulates ­(TSP)­ samples­ collected ­monthly,­ during­ summer,­ autumn,­ winter­ and­ spring­ of­ 2000­ and­ grouped­ into­ three­ pools,­ January-April;­ May-August;­ September- December,­ and­ three­ samples­ of­ particulate­ matter­ PM10,­ corresponding­ to­ the­ months­ of­ February,­ June­ and­ August­ of­ 2005 ­were­ analyzed. ­The­ organic ­extracts,­ obtained­ by­ sonication­ with­ dichloromethane,­ were­ previously­ investigated­ for­ the­ presence of nitrocompounds with mutagenicity activity, using Salmonella/microsome assay with sensitive strains for these substances.­ The ­mutagenic ­response­ was­ observed­ for­ all samples ­in­ different­ levels, ­demonstrating­ the­ presence ­of­ mono­ and­ dinitro-PAHs­ in­ the­ extracts.­ The­ chromatographic­ analysis­ allowed­ verifying­ the­ predominance­ of­ dinitronaphthalenes­ for­ the ­samples­ corresponding­ to­ the­ winter ­months,­ both ­for­ PTS­ sample,­ May-August,­ and­ PM10­ samples,­ relative­ to ­June­ and­ August.­ These ­results ­allowed­ characterizing, ­in ­agreement­ with ­the ­mutagenic ­assay,­ the ­presence ­of­ nitronaphthalenes­ in­ the­ samples.
Evaluation of the Genotoxicity of Petroleum Refinery Effluents Using the Comet Assay in Oreochromis niloticus (Nile tilapia)
Authors: Hoshina M. M. , Marin-Morales M. A.
Published: September 2010

In this study, the genotoxic effects of effluent and water samples from areas (Atibaia and Jaguarí rivers) related to a petroleum refinery were assessed by comet assay carried out in erythrocytes of Oreochromis niloticus (Nile tilapia). It was registered, for the negative control test (pure ground water), the lowest levels of nucleus with damage, followed by the waters collected in the Jaguarí river (environmental control). It was observed a higher level of nucleus with damage in the fishes exposed to the refinery effluents samples, which decrease with the increasing treatments levels. It was also observed, in relation to the negative control, a genotoxic effect in the Atibaia river sample collected after the effluents discharge. The results showed that, even after the treatments, the petroleum refinery effluents induced genotoxicity in the exposed fishes.
Baseline levels and trends of ground level ozone in Canada and the United States
Authors: Chan E. , Vet R. J.
Published: September 2010

Abstract. A statistical method was developed to extract baseline levels of ground level ozone in Canada and the US, and to quantify the temporal changes of baseline ozone levels on annual, seasonal, diurnal and decadal scales for the period 1997 to 2006 based on ground-level observations from 97 non-urban monitoring sites. Baseline ozone is defined here as ozone measured at a given site in the absence of strong local influences. The quantification of baseline levels involved using a Principal Component Analyses (PCA) to derive groups of commonly-varying sites in contiguous regions by season, followed by using backward air parcel trajectories to systematically select ozone mixing ratios associated with the baseline condition in each of the PCA-derived regions. Decadal trends were estimated by season for each of the regions using a generalized linear mixed model (GLMM). Baseline ozone mixing ratios determined by this method were found to vary geographically and seasonally. For the 1997–2006 period, baseline mixing ratios were calculated for annual and seasonal periods in seven regions of North America based on multi-site multi-year averages of the baseline data sets. The annual average (±1 standard deviation) baseline mixing ratios for the regions are as follows: Continental Eastern Canada=30±9 ppb, Continental Eastern US=30±10 ppb, Coastal Eastern Canada=27±9 ppb, Coastal Western Canada=19±10 ppb; Coastal Western US=39±10 ppb, Continental Western Canada=28±10 ppb and Continental Western US=46±7 ppb. Trends in the baseline mixing ratios were also found to vary by season and by geographical region. On a decadal scale, increasing baseline ozone trends (temperature-adjusted) were observed in all seasons along the Pacific coasts of Canada and the US, although the trends in California were not statistically significant. In the coastal zone of Pacific Canada, positive trends were found with a rate of increase of 0.28±0.26, 0.72±0.55, and 0.93±0.41 ppb/a in spring (MAM), summer (JJA) and winter (DJF), respectively. In the Atlantic coastal region, the trends were also positive in 3 of the 4 seasons (but only significantly so in MAM). In the high ozone precursor emission areas of the Eastern United States, decadal trends in baseline ozone are, in general, negative in the spring, summer and fall and appear to be controlled by the strong within-region changes induced by decreasing ozone precursor emissions.