Macroeconomic Forecasting with Mixed Frequency Data : Forecasting US output growth and inflation.

Although many macroeconomic series such as US real output growth are sampled quarterly, many potentially useful predictors are observed at a higher frequency. We look at whether a recently developed mixed data-frequency sampling (MIDAS) approach can improve forecasts of output growth and inflation. We carry out a number of related real-time forecast comparisons using various indicators as explanatory variables. We find that MIDAS model forecasts of output growth are more accurate at horizons less than one quarter using coincident indicators ; that MIDAS models are an effective way of combining information from multiple indicators ; and that the forecast accuracy of the unemployment-rate Phillips curve for inflation is enhanced using the MIDAS approach.Data frequency ; multiple predictors ; combination ; real-time forecasting

Real-time Forecasting of Inflation and Output Growth in the Presence of Data Revisions

We show how to improve the accuracy of real-time forecasts from models that include au-toregressive terms by estimating the models on ‘lightly-revised’data instead of using data from the latest-available vintage. Forecast accuracy is improved by reorganizing the data vintages employed in the estimation of the model in such a way that the vintages used in estimation are of a similar maturity to the data in the forecast loss function. The size of the expected reductions in mean squared error depend on the characteristics of the data revision process. Empirically, we …nd RMSFE gains of 2-4% when forecasting output growth and in‡ation with AR models, and gains of the order of 8% with ADL models.real-time data ; news and noise revisions ; optimal forecasts ; multi-vintage models. JEL Classification: C53

First Announcements and Real Economic Activity

The recent literature suggests that first announcements of real output growth in the US have predictive power for the future course of the economy. We show that this need not point to a behavioural relationship, whereby agents respond to the announcement, but may instead simply be a by-product of the data revision process. Initial estimates are subsequently subject to a number of rounds of revisions: the nature of these revisions is shown to be key in determining any apparent relationship between first announcements and the future course of the economy.Announcements ; real activity ; data measurement ; revisions

Quantile Forecasts of Daily Exchange Rate Returns from Forecasts of Realized Volatility

Quantile forecasts are central to risk management decisions because of the widespread use of Value-at-Risk. A quantile forecast is the product of two factors : the model used to forecast volatility, and the method of computing quantiles from the volatility forecasts. In this paper we calculate and evaluate quantile forecasts of the daily exchange rate returns of five currencies. The forecasting models that have been used in recent analyses of the predictability of daily realized volatility permit a comparison of the predictive power of different measures of intraday variation and intraday returns in forecasting exchange rate variability. The methods of computing quantile forecasts include making distributional assumptions for future daily returns as well as using the empirical distribution of predicted standardized returns with both rolling and recursive samples. Our main ?ndings are that the HAR model provides more accurate volatility and quantile forecasts for currencies which experience shifts in volatility, such as the Canadian dollar, and that the use of the empirical distribution to calculate quantiles can improve forecasts when there are shifts.realized volatility ; quantile forecasting ; MIDAS ; HAR ; exchange rates

Coqueiro: recomendações de cultivo.

bitstream/item/49373/1/fd190001.pdf1 folder

Discrete Wigner functions and quantum computational speedup

In [Phys. Rev. A 70, 062101 (2004)] Gibbons et al. defined a class of discrete Wigner functions W to represent quantum states in a finite Hilbert space dimension d. I characterize a set C_d of states having non-negative W simultaneously in all definitions of W in this class. For d<6 I show C_d is the convex hull of stabilizer states. This supports the conjecture that negativity of W is necessary for exponential speedup in pure-state quantum computation.Comment: 7 pages, 2 figures, RevTeX. v2: clarified discussion on dynamics, added refs., published versio

Sinais climáticos em anéis de crescimento de Cedrela fissilis em diferentes tipologias de florestas ombrófilas do Sul do Brasil.

Os anéis de crescimento de Cedrela fissilis foram analisados em duas unidades fitogeográficas do estado do Paraná, em áreas de Florestas Ombrófilas Densa e Mista, litoral e planalto, no domínio da Floresta Atlântica, buscando encontrar sinais climáticos nas séries radiais temporais de anéis de crescimento. As áreas não apresentam estação seca bem definida, com precipitações bem distribuídas ao longo do ano. Na área do litoral, as temperaturas são altas e constantes durante todo o ano, enquanto que na área do planalto as temperaturas são mais amenas, ocorrendo considerável variação durante o ano. Nas duas áreas foram coletadas 3-4 amostras radiais dos indivíduos selecionados, sendo 15 no litoral e 21 no planalto. Os anéis de crescimento foram marcados, mensurados, submetidos ao controle de qualidade por meio do programa COFECHA® e as cronologias foram geradas utilizando o programa ARSTAN®. Sinais climáticos nas séries foram identificados utilizando-se Correlações de Pearson. As séries analisadas provenientes da área de planalto apresentaram melhores correlações com as variáveis temperatura e precipitação, sendo identificados sinais climáticos, enquanto que as séries do litoral não puderam ser datadas com total acurácia. É atribuída a hipótese da competição, principalmente por luz, para explicar a dificuldade na datação dos indivíduos do litoral

Dendroecology of Gymnanthes klotzschiana Müll. Arg. trees, naturally growing in Northern Uruguay.

Ameridendro

Bananeira: recomendações de cultivo.

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