An in vitro study of the dynamic features of the major histocompatibility complex class I complex relevant to its role as a versatile peptide-receptive molecule

The major histocompatibility complex class I complex consists of a heavy chain and a light chain (β2-microglobulin, β2m), which assemble with a short endogenously derived peptide in the endoplasmic reticulum. The class I peptide can be directly exchanged, either at the cell surface or, as recently described, in vesicles of the endocytic compartments, thus allowing exogenous peptides to enter the class I presentation pathway. To probe the interactions between the components of the class I molecule, we analyzed the exchange of peptide and β2m by using purified, recombinant H2-Kb/peptide complexes in a cell-free in vitro system. The exchange of competitor peptide was primarily dependent on the off-rate of the original peptide in the class I binding groove. Peptide exchange was not enhanced by the presence of exogenous β2m, as exchange occurred to the same extent in its absence. Thus, the exchange of peptide and β2m are independent events. The exchange rate of β2m also was not affected by the dissociation rates of the original peptides. Furthermore, peptides could substantially exchange into class I molecules over a pH range of 5.5 to 7.5, conditions prevalent in certain endocytic compartments. We conclude that the dynamic properties of the components of class I molecules explain its function as a highly peptide-receptive molecule. The major histocompatibility complex class I can readily receive peptides independent of the presence of exogenous β2m, even at a low pH. Such properties are relevant to class I peptide acquisition, which can occur at the cell surface, as well as in specialized endosomes.

Regulation of Apoplastic NH4+ Concentration in Leaves of Oilseed Rape1

Regulation of apoplastic NH4+ concentration in leaves of oilseed rape (Brassica napus L.) was studied using a vacuum-infiltration technique that allowed controlled manipulations of the apoplastic solution. In leaves infiltrated with NH4+-free solution, the apoplastic NH4+ concentration returned in less than 1.5 min to the preinfiltration level of 0.8 mm. Infiltrated 15NH4+ was rapidly diluted by 14NH4+/14NH3 effluxed from the cell. The exchange rate of 15N/14N over the apoplast due to combined 14N efflux from the symplast and 15N influx from the apoplastic solution was 29.4 μmol g−1 fresh weight h−1 between 0 and 5 min after infiltration. The net uptake of NH4+ into the leaf cells increased linearly with apoplastic NH4+ concentrations between 2 and 10 mm and could be partially inhibited by the channel inhibitors La3+ and tetraethylammonium and by Na+ and K+. When apoplastic pH increased from 5.0 to 8.0, the steady-state apoplastic NH4+ concentration decreased from 1.0 to 0.3 mm. Increasing temperature increased the rate of NH4+ net uptake and reduced the apoplastic steady-state NH4+ concentration. We conclude that the apoplastic solution in leaves of oilseed rape constitutes a highly dynamic NH4+ pool.

Choques de oferta e política monetária na economia brasileira: Uma análise do impacto dos preços das commodities na inflação entre 2002 e 2014

Há mais de uma década o controle dos níveis de preço na economia brasileira é realizado dentro do escopo do Regime de Metas de Inflação, que utiliza modelos macroeconômicos como instrumentos para guiar as tomadas de decisões sobre política monetária. Após um período de relativo êxito (2006 - 2009), nos últimos anos apesar dos esforços das autoridades monetárias na aplicação das políticas de contenção da inflação, seguindo os mandamentos do regime de metas, esta tem se mostrado resistente, provocando um debate em torno de fatores que podem estar ocasionando tal comportamento. Na literatura internacional, alguns trabalhos têm creditado aos choques de oferta, especialmente aos desencadeados pela variação dos preços das commodities, uma participação significativa na inflação, principalmente em economias onde os produtos primários figuram como maioria na pauta exportadora. Na literatura nacional, já existem alguns trabalhos que apontam nesta mesma direção. Sendo assim, buscou-se, como objetivo principal para o presente estudo, avaliar como os choques de oferta, mais especificamente os choques originados pelos preços das commodities, têm impactado na inflação brasileira e como e com que eficiência a política monetária do país tem reagido. Para tanto, foi estimado um modelo semiestrutural contendo uma curva de Phillips, uma curva IS e duas versões da Função de Reação do Banco Central, de modo a verificar como as decisões de política monetária são tomadas. O método de estimação empregado foi o de Autorregressão Vetorial com Correção de Erro (VEC) na sua versão estrutural, que permite uma avaliação dinâmica das relações de interdependência entre as variáveis do modelo proposto. Por meio da estimação da curva de Phillips foi possível observar que os choques de oferta, tanto das commodities como da produtividade do trabalho e do câmbio, não impactam a inflação imediatamente, porém sua relevância é crescente ao longo do tempo chegando a prevalecer sobre o efeito autorregressivo (indexação) verificado. Estes choques também se apresentaram importantes para o comportamento da expectativa de inflação, produzindo assim, uma indicação de que seus impactos tendem a se espalhar pelos demais setores da economia. Através dos resultados da curva IS constatou-se a forte inter-relação entre o hiato do produto e a taxa de juros, o que indica que a política monetária, por meio da fixação de tal taxa, influencia fortemente a demanda agregada. Já por meio da estimação da primeira função de reação, foi possível perceber que há uma relação contemporânea relevante entre o desvio da expectativa de inflação em relação à meta e a taxa Selic, ao passo que a relação contemporânea do hiato do produto sobre a taxa Selic se mostrou pequena. Por fim, os resultados obtidos com a segunda função de reação, confirmaram que as autoridades monetárias reagem mais fortemente aos sinais inflacionários da economia do que às movimentações que acontecem na atividade econômica e mostraram que uma elevação nos preços das commodities, em si, não provoca diretamente um aumento na taxa básica de juros da economia.

Estimating and forecasting generalized fractional Long memory stochastic volatility models

In recent years fractionally differenced processes have received a great deal of attention due to its flexibility in financial applications with long memory. This paper considers a class of models generated by Gegenbauer polynomials, incorporating the long memory in stochastic volatility (SV) components in order to develop the General Long Memory SV (GLMSV) model. We examine the statistical properties of the new model, suggest using the spectral likelihood estimation for long memory processes, and investigate the finite sample properties via Monte Carlo experiments. We apply the model to three exchange rate return series. Overall, the results of the out-of-sample forecasts show the adequacy of the new GLMSV model.

Adsorption and first stages of polymerization of aniline on platinum single crystal electrodes

The present communication studies the adsorption of aniline on platinum single crystal electrodes and the electrochemical properties of the first layers of polyaniline(PANI) grown on those platinum surfaces. The adsorption process was studied in aqueous acidic solution (0.1 M HClO4) and the electrochemical properties of thin films of PANI in both aqueous (1 M HClO4) and non-aqueous media (tetrabutyl ammonium hexafluorophosphate (TBAPF6) with additions of methanesulphonic acid in acetonitrile). First of all, it was found that the adsorption of aniline on platinum single crystal surfaces is a surface sensitive process, and even more important that the adsorption features found at low concentrations (5 × 10−5 M) can be directly correlated to the electrochemical properties of thin films of PANI in the very early stages of polymerization. The Pt(1 1 0) surface was found to be more suitable to obtain polymers with more reversible redox transitions when studied in aqueous media (1 M HClO4). This is in good agreement with the higher polymerization rates found on this surface compared to Pt(1 0 0) and Pt(1 1 1). Finally the differences in ionic exchange rate were greatly enhanced when they were studied in organic media. The AC 250 Hz response in the case of the thin films synthesized on Pt(1 1 0) is about twice greater than that obtained in the other basal planes using polymer layers with the same thickness.

British business and the Euro. ACES Cases No. 2008.2

During the Maastricht Treaty negotiations, the United Kingdom obtained an opt-out option on Economic and Monetary Union (EMU). When Tony Blair came to power, he promised there would be a referendum on the euro if the government decided it was in the national interest to join. Many believed Tony Blair intended to call and try to win a referendum on the euro. Therefore, in the late 1990s, the debate over the euro raged in Britain, filling the pages of the tabloids and the minds of many Britons. In this paper based on empirical research conducted in London in 2005-06, I investigate whether the business sector had a clear preference on the issue of British membership in the EMU and tried to influence the government‟s decision. I use Jeffry Frieden's model of interest group preferences regarding exchange-rate policies to develop hypotheses regarding the position of the business sector on the euro. Research findings reveal that the business sector was divided on the issue of euro membership exactly as Frieden's model predicts. However, the intensity of business preferences decreased overtime. By the end of Tony Blair's second term, the business sector had become neutral on the issue of the euro.

Manufactured Exports and FDI in Southern Mediterranean Countries: Evolution, determinants and prospects. MEDPRO Technical Report No. 14/April 2012

This paper investigates the evolution and determinants of manufactured exports and foreign direct investment (FDI) in 11 southern Mediterranean countries over the period 1985–2009, as well as their prospects under different scenarios pertaining to the development of the determinants. The econometric analysis confirms the role of exchange rate depreciation, the openness of the economy and the quality of institutions and infrastructure in fostering manufactured exports and FDI inflows in the region. The assessment of the prospects suggests that a scenario of deeper integration with the EU entails superior performance for manufactured exports and FDI compared with either the status quo or less integration with the EU but greater integration within the region.

Le role des politiques monétaires et la convergence macroeconomique sur le développement des systèmes financiers dans les pays du sud de la Méditerranée. = The role of monetary policies and macroeconomic convergence in the development of financial systems in south Mediterranean countries. MEDPRO Technical Report No. 12/April 2012

This MEDPRO Technical Report shows that the monetary and exchange rate policies conducted by central banks in the South Mediterranean region display apparent homogeneity in their operational frameworks, albeit with some specificities and differing degrees of advancement. While central banks state that price stability is their ultimate objective, failures to control interest rates as operational objectives of monetary policy result in monetary authorities resorting to quantitative approaches to monetary policy, meaning that monetary aggregates and credit targets are being used as intermediate targets of monetary policy. An econometric exercise limited to Maghreb countries (Algeria, Morocco, and Tunisia) has been conducted to analyse the potential scenarios of convergence and monetary policy coordination. Given the high structural heterogeneity and the slow pace of real convergence due to weak commercial integration in the Maghreb, results nevertheless show alternative dynamics in the integration of effective nominal exchange rates, as well as a complete convergence dynamic in exchange rate policies. Partial convergence of monetary policies regarding the stabilisation of inflation rates remains an open option for a transitional phase where financial integration is low.

Les enjeux de la libéralisation des comptes de capital dans les pays du sud de la Méditerranée. = Challenges arising from Capital Account Liberalisation in the Countries of the South Mediterranean Region. MEDPRO Technical Report No. 11/March 2012

This MEDPRO Technical Report confirms the importance of commercial openness and macroeconomic performance (i.e. the control of inflation and stability of current account balance and exchange rate) on growth dynamics in the south Mediterranean countries. In particular, the positive impact of capital account liberalisation is conditioned by the imperative reinforcement of institutional quality, country risk reduction, and government stability. An examination of the Tunisian case shows that only sectors subject to tariff dismantlement within the framework of the Association Agreement with the EU appear to benefit from capital account liberalisation. Furthermore, the report shows that a scenario of capital account liberalisation requires the anticipation of monetary policy reaction functions. It follows that the mechanisms for interest rate adjustment, or inter alia, the interest rates’ reaction to price fluctuations, are weakly volatile. In turn, the analysis shows that an active control of inflation mismatches occurs essentially through exchange rate corrections, thus highlighting the greater interest central banks have in exchange rate stability over real stability. A capital account liberalisation scenario would hence impose a tightening of monetary policy.

Creating Stability: National Preferences and the Origins of European Monetary System. CES Germany & Europe Working Papers, No. 00.9, December 2000

This essay compares the preferences of France, Italy, and Britain on the creation of the European Monetary System in 1978-1979, especially the Exchange Rate Mechanism, which stabilised nominal exchange rates. My claim is that the different conclusions reached by the governments (France and Italy in, Britain out) cannot be explained by economic circumstances or by interests, and I elaborate an intervening institutional variable which helps explain preferences. Deducing from spatial theory that where decisionmakers `sit' on the left-right spectrum matters to their position on the EMS, I argue that domestic constitutional power-. sharing mechanisms privilege certain actors over others in a predictable and consistent way. Where centrists were in power, the government's decision was to join. Where left or right extremists were privileged, the government's decision was negative. The article measures the centrism of the governments in place at the time, and also reviews the positions taken by the national political parties in and out of government. It is intended to contribute to the growing comparativist literature on the European Union, and to the burgeoning literature on EU-member-state relations.

How Germany Benefits from the Euro in Economic Terms. Policy Brief #2013/01

There can be no doubt about the fact that Germany benefits from the euro in a significant number of ways. For ex-ample, monetary union membership helps to reduce the cost of international trade, and provides protection against excessive exchange rate volatility. This means that even if Germany had to write off a large percentage of the loans that it has made available to the heavily indebted states of southern Europe as part of the various euro rescue measures, the economic advantages of its membership of the monetary union would continue to predominate. Reverting to the deutschmark would thus be disadvantageous even in purely economic terms.

Institutions and Growth in Europe. CEPS Working Document No. 421, April 2016

This paper provides empirical evidence in support of the view that the quality of institutions is an important determinant of long-term growth of European countries. When also taking into account the initial level of GDP per capita and government debt, cross-country institutional differences can explain to a great extent the relative long-term GDP performance of European countries. It also shows that an initial government debt level above a threshold (e.g. 60-70%) coupled with institutional quality below the EU average tends to be associated with particularly poor long-term real growth performance. Interestingly, the detrimental effect of high debt levels on long-term growth seems cushioned by the presence of very sound institutions. This might be because good institutions help to alleviate the debt problem in various ways, e.g. by ensuring sufficient fiscal consolidation in the longer-run, allowing for better use of government expenditures and promoting sustainable growth, social fairness and more efficient tax administration. The quality of national institutions seems to enhance the long-term GDP performance across a large sample of countries, also including OECD countries outside Europe. The paper offers some evidence that, in the presence of good institutions, conditions for catching-up seem generally good also for euro-area and fixed exchange rate countries. Looking at sub-groupings, it seems that sound institutions may be particularly important for long-term growth in the countries where the exchange rate tool is no longer available (and where also sovereign debt is high), and less so in the countries with flexible exchange rate regimes. However, this result is preliminary and requires further research. The empirical findings on the importance of institutions are robust to various measures of output growth, different measures of institutional indicators, different sample sizes, different country groupings and to the inclusion of additional control variables. Overall, the results tend to support the call for structural reforms in general and reforms enhancing the efficiency of public administration and regulation, the rule of law and the fight against rent-seeking and corruption in particular.

Essays on International Asset Allocation and Pricing

Thesis (Ph.D.)--University of Washington, 2016-06

The price elasticity of the Euro to movements in foreign reserves through European Central Bank intevention

The Euro has been used as the largest weighting element in a basket of currencies for forex arrangements adopted by several Central European countries outside the European Union (EU). The paper uses a new time-series approach to examine the relationship between the Euro exchange rate and the level of foreign reserves. It employs Zero-no-zero (ZNZ) patterned vector error-correction (VECM) modelling to investigate Granger causal relations among foreign reserves, the European Monetary Union money supply and the Euro exchange rate. The findings confirm that foreign reserves may influence movements in the Euro's exchange rate. Further, ZNZ patterned VECM modelling with exogenous variables is used to estimate the amount of foreign reserves currently required in order to again achieve a targetted Euro exchange rate

ANALISANDO A RELAÇÃO DOS VOLUMES DE EXPORTAÇÃO E DE IMPORTAÇÃO, PIB, TAXAS DE CÂMBIO E INFLAÇÃO NO PERÍODO DE 2004 A 2014.

Esta dissertação visa deslumbrar uma análise macroeconômica do Brasil, especialmente no que se refere à relação dos índices mensais dos volumes das exportações e das importações com os volumes mensais do PIB, da Taxa SELIC e as Taxas de Câmbio, conforme dados coletados no período de janeiro de 2004 a dezembro de 2014, através de pesquisa literária referente aos históricos sobre cada conceito envolvido no âmbito da macroeconomia das varáveis estudadas. Foi realizado um estudo de caso embasado em dados de sites governamentais, no período delimitado, empregando-se o método de regressão linear, com base na Teoria da correlação de Pearson, demonstrando os resultados obtidos no período do estudo para as varáveis estudadas. Desta maneira, conseguiu-se estudar e analisar como as variáveis dependentes (resposta): volume das exportações e volume das importações estão relacionadas com as varáveis independentes (explicativas): PIB, Taxa Selic e taxa de Câmbio. Os resultados apurados no presente estudo permitem identificar que existe correlação moderada e negativa, quando analisadas a Taxa Selic e a Taxa de Câmbio com os volumes das exportações e das importações, enquanto o PIB apresenta correlação forte e positiva na análise com os volumes das exportações e das importações. Palavras-