Determinantes da Inflação em Cabo Verde

Um incremento do nível geral de preços pode ter impacto marcante no bem-estar económico e social, já que há perda de valor da moeda e consequente deterioração do poder de compra da população, conduzindo assim ao agravamento das condições e custo de vida. Contudo, torna-se necessário investigar as causas (fatores determinantes) da inflação, pois é uma das etapas fundamentais para o controlo do processo inflacionário. Neste sentido, o presente estudo tem como objetivo principal averiguar quais os determinantes da inflação em Cabo Verde. Para tal foi utilizado o método de co-integração, recentemente proposto por Pesaran et al. (2001) – Bound Test. Os resultados obtidos evidenciam que as componentes sazonais, cambiais, monetárias, orçamentais e externas explicam grande parte da Inflação em Cabo Verde.

The credit ratings game

The collapse of so many AAA-rated structured finance products in 2007-2008has brought renewed attention to the causes of ratings failures and the conflicts of interestin the Credit Ratings Industry. We provide a model of competition among Credit RatingsAgencies (CRAs) in which there are three possible sources of conflicts: 1) the CRA conflictof interest of understating credit risk to attract more business; 2) the ability of issuersto purchase only the most favorable ratings; and 3) the trusting nature of some investorclienteles who may take ratings at face value. We show that when combined, these give riseto three fundamental equilibrium distortions. First, competition among CRAs can reducemarket efficiency, as competition facilitates ratings shopping by issuers. Second, CRAs aremore prone to inflate ratings in boom times, when there are more trusting investors, andwhen the risks of failure which could damage CRA reputation are lower. Third, the industrypractice of tranching of structured products distorts market efficiency as its role is to deceivetrusting investors. We argue that regulatory intervention requiring: i) upfront paymentsfor rating services (before CRAs propose a rating to the issuer), ii) mandatory disclosure ofany rating produced by CRAs, and iii) oversight of ratings methodology can substantiallymitigate ratings inflation and promote efficiency.

Separated by a common currency? Evidence from the Euro changeover

We study the price convergence of goods and services in the euro area in 2001-2002. To measure the degree of convergence, we compare the prices of around 220 items in 32 European cities. The width of the border is the price di¤erence attributed to the fact that the two cities are in different countries. We find that the 2001 European borders are negative, which suggests that the markets were very integrated before the euro changeover. Moreover, we do not identify an integration effect attributable to the introduction of the euro. We then explore the determinants of the European borders. We find that different languages, wealth and population differences tend to split the markets. Historical inflation, though, tends to lead to price convergence.

What explains the Great Moderation in the US? A structural analysis

This paper investigates what has caused output and inflation volatility to fall in the USusing a small scale structural model using Bayesian techniques and rolling samples. Thereare instabilities in the posterior of the parameters describing the private sector, the policyrule and the standard deviation of the shocks. Results are robust to the specification ofthe policy rule. Changes in the parameters describing the private sector are the largest,but those of the policy rule and the covariance matrix of the shocks explain the changes most.

The transmission of US shocks to Latin America

I study whether and how US shocks are transmitted to eight Latin American countries. US shocks are identified using sign restrictions and treated as exogenous with respect to Latin American economies. Posterior estimates for individual and average effects are constructed. US monetary shocks produce significant fluctuations in Latin America, but real demand and supply shocks do not. Floaters and currency boarders display similar output but different inflation and interest rate responses. The financial channel plays a crucial role in the transmission. US disturbances explain important portions of the variability of LatinAmerican macrovariables, producing continental cyclical fluctuations and, in two episodes, destabilizing nominal exchange rate effects. Policy implications are discussed.

Pitfalls in the modeling of forward-looking price setting and investment decisions

The present paper makes progress in explaining the role of capital for inflation and output dynamics. We followWoodford (2003, Ch. 5) in assuming Calvo pricing combined with a convex capital adjustment cost at the firm level. Our main result is that capital accumulation affects inflation dynamics primarily through its impact on the marginal cost. This mechanism is much simpler than the one implied by the analysis in Woodford's text. The reason is that his analysis suffers from a conceptual mistake, as we show. The latter obscures the economic mechanism through which capital affects inflation and output dynamics in the Calvo model, as discussed in Woodford (2004).

A medium-scale open economy model of Australia

We estimate an open economy dynamic stochastic general equilibrium (DSGE)model of Australia with a number of shocks, frictions and rigidities, matching alarge number of observable time series. We find that both foreign and domesticshocks are important drivers of the Australian business cycle.We also find that theinitial impact on inflation of an increase in demand for Australian commoditiesis negative, due to an improvement in the real exchange rate, though there is apersistent positive effect on inflation that dominates at longer horizons.

Monetary policy and exchange rate volatility in a small open economy

We lay out a small open economy version of the Calvo sticky price model, and show how the equilibrium dynamics can be reduced to simple representation in domestic inflation and the output gap. We use the resulting framework to analyze the macroeconomic implications of three alternative rule-based policy regimes for the small open economy: domestic inflation and CPI-based Taylor rules, and an exchange rate peg. We show that a key difference amongthese regimes lies in the relative amount of exchange rate volatility that they entail. We also discuss a special case for which domestic inflation targeting constitutes the optimal policy, and where a simple second order approximation to the utility of the representative consumer can be derived and used to evaluate the welfare losses associated with the suboptimal rules.

Is the observed persistence spurious? A test for fractional integration versus short memory and structural breaks

Although it is commonly accepted that most macroeconomic variables are nonstationary, it is often difficult to identify the source of the non-stationarity. In particular, it is well-known that integrated and short memory models containing trending components that may display sudden changes in their parameters share some statistical properties that make their identification a hard task. The goal of this paper is to extend the classical testing framework for I(1) versus I(0)+ breaks by considering a a more general class of models under the null hypothesis: non-stationary fractionally integrated (FI) processes. A similar identification problem holds in this broader setting which is shown to be a relevant issue from both a statistical and an economic perspective. The proposed test is developed in the time domain and is very simple to compute. The asymptotic properties of the new technique are derived and it is shown by simulation that it is very well-behaved in finite samples. To illustrate the usefulness of the proposed technique, an application using inflation data is also provided.

Analysis of antiviral immunity in primary and chronic infections

Several evidences in humans underscored the contribution of CD4 and CD8 T-cell responses in controlling viral and bacterial infections. However, CD4 and CD8 Τ cells have distinct and specific effector functions leading to a hierarchical importance in responding to different types of pathogens. In this context, the present work aimed to investigate distinct CD8 T-cell features potentially influencing T-cell efficacy against viral infection. To achieve this-objective, CD8 Τ cells derived from HIV-infected patients and healthy donors harbouring virus-specific immune responses or immunized with an HTV vaccine candidate were studied. In particular, we performed a comprehensive cross-sectional and longitudinal analysis to characterize the function, the phenotype and the functional avidity of HIV-specific CD8 Τ cells during acute (PHI) and chronic infection and, in particular, we investigated immunological parameters potentially associated with the functional avidity of HIV-specific CD8 Τ cells. In addition, we studied the expression pattern of co-inhibitory molecules and the influence of CD 160 on the functions of CD8 Τ cells in absence of chronic infections. From these analyses we observed that the functional avidity of HIV-specific CD8 T- cell responses was significantly lower in acute than in chronic infection, but was not different between chronic progressive and non-progressive patients. Functional avidity remained low after several years of antiretroviral therapy in PHI patients, but increased in patients experiencing a virus rebound following treatment interruption in association with a massive renewal of the global CD8 complementarity-determining region 3 of the TCR. The functional avidity was also directly associated to T-cell exhaustion. In individuals with no sign of HIV or Hepatitis A, Β or C virus infection, CD8 Τ cells expressed higher levels of co-inhibitory molecules than CD4 Τ cells and this was dependent on the stage of T-cell differentiation and activation. The expression of CD 160 impaired the proliferation capacity and IL-2 production of CD8 Τ cells and was reduced upon CD8 T-cell activation, entitling CD 160 as unique marker of CD8 T-cell exhaustion. The CD 160 blockade restored the proliferation capacity of virus-specific CD8 Τ cells providing a potential new target for immunotherapy. All together, these results expand our knowledge regarding the interplay between the immune system and the viruses. - De nombreuses études chez l'Homme ont mis en évidence la contribution des réponses cellulaires Τ CD4 et CD8 dans le contrôle des infections virales et bactériennes. En particulier, les lymphocytes Τ ont différentes fonctions effectrices spécifiques qui leur confèrent un rôle clé lors d'infections par différents pathogènes. Ce travail vise à étudier différentes caractéristiques des cellules Τ CD8 affectant l'efficacité des réponses cellulaires contre les virus. Pour atteindre cet objectif nous avons étudié les cellules Τ CD8 provenant de patients infectés par le VIH et de donneurs sains avec des réponses immunitaires naturelles ou vaccinales contre des virus. Nous avons effectué plusieurs analyses transversales et longitudinales des fonctions, du phénotype et de l'avidité fonctionnelle des lymphocytes Τ CD8 spécifiques au VIH au cours d'infections aiguës et chroniques; en particulier, nous avons étudié les paramètres immunologiques qui pourraient être associés à l'avidité fonctionnelle. De plus, nous avons investigué le profil d'expression des principales molécules co-inhibitrices et en particulier le rôle du CD 160 dans les fonctions des lymphocytes Τ CD8. Sur la base de ces analyses, nous avons constaté que l'avidité fonctionnelle des cellules Τ CD8 spécifiques au VIH était significativement plus faible lors infections aiguës que lors d'infections chroniques, mais n'était, par contre, pas différente entre les patients avec des infections chroniques progressives et non progressives. L'avidité fonctionnelle reste faible après plusieurs années de traitement antirétroviral, mais augmente chez les patients subissant un rebond viral, et donc exposés à des hautes virémies, suite à l'interruption du traitement. Cette augmentation d'avidité des lymphocytes Τ CD8, liée à un épuisement fonctionnel accru, était quantitativement directement associée à un renouvellement massif du TCR. Indépendamment de l'infection par le VIH, les cellules Τ CD8 expriment des niveaux plus élevés de molécules co-inhibitrices (PD-1, 2B4 et CD 160) par rapport aux cellules Τ CD4 et ceci dépend de leur stade de différenciation et d'activation. En particulier, CD 160 semble être un marqueur clé d'épuisement cellulaire des cellules Τ CD8, et donc une nouvelle cible potentielle pour l'immunothérapie, car a) son expression réduit la capacité proliférative et la production d'IL-2 b) CD 160 diminue suite à 1'activation et c) le blocage de CD 160 redonne la capacité proliférative aux cellules Τ CD8 spécifiques aux virus. - Le système immunitaire est un ensemble de cellules, tissus et organes indispensables pour limiter l'entrée des pathogènes à travers la peau et les muqueuses. Parmi les différentes cellules composant le système immunitaire, les cellules Τ CD4 et CD8 sont fondamentales pour le contrôle des infections virales et bactériennes. Les moyens pour combattre les différents pathogènes peuvent être cependant très variables. Les cellules Τ CD8, qui sont indispensables pour la lutte contre les virus, peuvent avoir différents niveaux de sensibilité; les cellules qui répondent à de faibles quantités d'antigène ont une forte sensibilité. Suite à une première infection virale, les cellules Τ CD8 ont une sensibilité plus faible que lors d'expositions répétées au même virus. En effet, la réexposition au pathogène induit une augmentation de sensibilité, grâce au recrutement et/ou à l'expansion de cellules Τ dotées d'une sensibilité plus élevée. Les cellules Τ CD8 avec une plus haute sensibilité semblent être caractérisées par une perte de fonctionnalité (épuisement fonctionnel associé à une haute expression de molécules dites inhibitrices). En absence d'infection, la fonction des molécules inhibitrices n'est pas encore clairement définie. Les cellules Τ CD8 montrent un niveau d'expression plus élevé de ces molécules par rapport aux cellules Τ CD4. Ceci dépend de l'état des cellules. Parmi ces molécules, le CD160 est associé à l'incapacité des cellules à proliférer et à produire de l'IL-2, une protéine importante pour la prolifération et la survie cellulaire. L'incapacité des cellules exprimant le CD 160 à proliférer en réponse à des virus peut être restaurée par le blocage fonctionnel du récepteur CD 160. Cette étude étoffe notre connaissance du rôle des cellules Τ CD8 ainsi que des conséquences induites par leur épuisement fonctionnel. Ces informations sont fondamentales pour le développement de nouvelles stratégies thérapeutiques et vaccinales.

Inflationary expectations during Germany's great slump

Was the German slump inevitable? This paper argues that -despite thespeed and depth of Germany's deflation in the early 1930s - fear ofinflation is evident in the bond, foreign exchange, and commodity marketsat certain critical junctures of the Great Depression. Therefore, policyoptions were more limited than many subsequent critics of Brüning'spolicies have been prepared to admit. Using a rational expectationsframework, we find strong evidence from the bondmarket to suggest fearof inflation. Futures prices also reveal that market participants werebetting on price increases. These findings are discussed in the contextof reparations and related to the need for a regime shift to overcomethe crisis.

"Marxisme et philosophie du langage" (1929) de V. Volochinov et sa réception chez R. Chor : deux voies du développement de la science du langage «marxiste» dans les années 1920 en Russie

Malgré le succès de  « Marxisme et philosophie du langage » (par la suite MPL) de V. Volochinov, ce texte n'a suscité que trois comptes rendus. Le quatrième est ébauché par A. Romm. Resté à l'état de notes, ce compte rendu est bien étudié par les chercheurs contemporains. En revanche, le compte rendu écrit par R. Chor n'a jamais été analysé de façon détaillée. Notre article a pour but de combler cette lacune et porte sur le contenu de l'analyse critique de MPL faite par Chor. Son examen révèle que le compte rendu écrit par cette dernière et MPL de Volochinov représentent la formulation de principes de base diamétralement opposés de la science du langage «marxiste». Cela se manifeste dans la réception des idées de F. de Saussure. Si Chor considère la conception de ce dernier comme fondement de la linguistique «théorique» portant sur la langue en tant que système de signes (ou de «signifiances» dans les termes de Chor), Volochinov rejette la théorie de Saussure. Il la considère comme «abstraite», d'où le nom «objectivisme abstrait» qu'il donne au saussurisme. En élaborant la philosophie du langage «marxiste», il s'appuie sur la néo-philologie idéaliste (les idées de Vossler et de son Ecole) définie dans MPL comme «subjectivisme individualiste». Volochinov propose d'étudier la «langue» comme fait réel, accessible à l'observation immédiate et non pas comme objet d'étude «théorique». Ce fait constitue une cible de la critique adressée par Chor à Volochinov

Do expectations matter? The Great Moderation revisited

We examine the role of expectations in the Great Moderation episode. We derive theoretical restrictions in a New-Keynesian model and test them using measures of expectations obtained from survey data, the Greenbook and bond markets. Expectations explain the dynamics of inflation and of interest rates but their importance is roughly unchanged over time. Systems with and without expectations display similar reduced form characteristics. Including or excluding expectations hardly changes the economic explanation of the Great Moderation. Results are robust to changes in the structure of the empirical model.

The variability of money velocity in a generalized cash-in-advance model

This paper presents a general equilibrium model of money demand wherethe velocity of money changes in response to endogenous fluctuations in the interest rate. The parameter space can be divided into two subsets: one where velocity is constant and equal to one as in cash-in-advance models, and another one where velocity fluctuates as in Baumol (1952). Despite its simplicity, in terms of paramaters to calibrate, the model performs surprisingly well. In particular, it approximates the variability of money velocity observed in the U.S. for the post-war period. The model is then used to analyze the welfare costs of inflation under uncertainty. This application calculates the errors derived from computing the costs of inflation with deterministic models. It turns out that the size of this difference is small, at least for the levels of uncertainty estimated for the U.S. economy.

A search theory of money and commerce with Neoclassical production

This paper advances a highly tractable model with search theoretic foundations for money and neoclassical growth. In the model, manufacturingand commerce are distinct and separate activities. In manufacturing,goods are efficiently produced combining capital and labor. In commerce,goods are exchanged in bilateral meetings. The model is applied to studythe effects of inßation on capital accumulation and welfare. With realisticparameters, inflation has large negative effects on welfare even though itraises capital and output. In contrast, with cash-in-advance, a deviceinformally motivated with bilateral trading, inflation depresses capitaland output and has a negligible effect on welfare.