591 research outputs found

    New Multi-Country Evidence on Purchasing Power Parity: Multi-Variate Unit Root Test Results

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    In this paper a likelihood-based multi-variate unit root testing framework is utilized to test whether the real exchange rates of G10 countries are non-stationary. The framework uses a likelihood ratio statistic which combines the information across all involved countries while retaining heterogeneous rates of mean reversion. This likelihood ratio statistic has an asymptotic distribution which can be typified as a summation of squared, univariate Dickey and Fuller (1979) distributions. Our multi-variate unit root tests indicate that bilateral G10 real exchange rates are stationary, irrespective of the numeraire country. On the other hand, the choice of the numeraire country seems to be of importance for the issue whether mean reversion rates across G10 real exchange rates are heterogeneous or homogeneous.

    Comparison of immunofluorescence and enzyme-linked immunosorbent assays for the serology of hantavirus infections.

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    Three enzyme-linked immunosorbent assay (ELISA) systems based upon different principles were developed for the serology of Hantaan virus infections and compared with an indirect immunofluorescence assay (IFA). The indirect IFA was carried out with gamma-irradiated Hantaan virus-infected and uninfected Vero E6 cells fixed with ethanol (-70 degrees C) or acetone (20 degrees C) on drop slides and a FITC-coupled sheep anti-human Ig preparation. Atypical staining in the IFA was avoided by using ethanol (-70 degrees C) instead of acetone (20 degrees C) fixation. In the first ELISA ('cell-assay'), Hantaan virus-infected or uninfected Vero E6 cells were used as antigens, which after gamma-irradiation were seeded into microtiter ELISA strips. Serial dilutions of human sera were incubated and specific antibodies were demonstrated with a horseradish peroxidase (HRPO)-conjugated sheep anti-human Ig preparation. In the second ELISA ('competition-assay') an affinity-purified human Ig preparation was used as a capture antibody for Hantaan virus antigen. After incubation of serial dilutions of human sera with this coat, the reactivity of the affinity purified anti-Hantaan virus Ig coupled to HRPO was determined. In the third ELISA ('complex trapping blocking [CTB]-assay') the same capture antibody was used to react with a mixture of the antigen and serial dilutions of human sera. The reactivity with the same HRPO conjugate was then determined. The results obtained in the respective assay systems with sera from people at risk or suspected of Hantaan virus infection coincided well. The CTB-ELISA proved to be faster and more sensitive than both the other ELISA systems, without giving more non-specific reactions: it detected almost all the IFA positive samples.(ABSTRACT TRUNCATED AT 250 WORDS

    Commodity prices, commodity currencies, and global economic developments

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    In this paper we seek to produce forecasts of commodity price movements that can systematically improve on naive statistical benchmarks, and revisit the forecasting performance of changes in commodity currencies as efficient predictors of commodity prices, a view emphasized in the recent literature. In addition, we consider different types of factor-augmented models that use information from a large data set containing a variety of indicators of supply and demand conditions across major developed and developing countries. These factor-augmented models use either standard principal components or partial least squares (PLS) regression to extract dynamic factors from the data set. Our forecasting analysis considers ten alternative indices and sub-indices of spot prices for three different commodity classes across different periods. We find that the exchange rate-based model and especially the PLS factor-augmented model are more prone to outperform the naive statistical benchmarks. However, across our range of commodity price indices we are not able to generate out-of-sample forecasts that, on average, are systematically more accurate than predictions based on a random walk or autoregressive specifications.

    Hantavirus infections in The Netherlands

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    During the Korean war between 1951-1953, an epidemic occurred among United Nations sanctioned military troops, characterized by fever, haemorrhages, shock and renal failure with a case fatality rate of up to 15%. This disease became known as Korean haemorrhagic fever [Smadel, 1951; Earle, 1954]. Despite extensive investigations at that time no etiologic agent could be identified. In the far east the oldest suggestive description of a similar disease had been made as early as 1000 years ago in a Chinese medicine book [Lee, 1982a]. During the American Civil War between 1862-1866 epidemics of "general dropsy" with renal involvement were noted among northern army troops. This disease was later called "Bright's disease" [Brown, 1916]. In Europe the first descriptions of the disease appeared in the early 1900's, after outbreaks in Russia and Scandinavia [Mayer, 1952; Myhrman, 1934; Zetterholm, 1934]. The Russians called the disease haemorrhagic nephroso-nephritis and the Scandinavians named it nephropathia epidemica (NE)

    Selective inhibitory effects of (S)-9-(3-hydroxy-2-phosphonyl-methoxypropyl)adenine and 1-(2'-deoxy-

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    From a selection of 25 antiviral compounds with specific anti-herpes activity or broad-spectrum antiviral properties, two compounds, namely (S)-9-(3-hydroxy-2-phosphonyl-methoxypropyl)adenine and 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-iodouracil, appeared particularly effective in inhibiting the cytopathogenicity of seal herpesvirus (phocid herpesvirus 1)

    Evaluation of six immunoassays for detection of dengue virus-specific immunoglobulin M and G antibodies

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    The performance of six commercially available immunoassay systems for the detection of dengue virus-specific immunoglobulin M (IgM) and IgG antibodies in serum was evaluated. These included two IgM and IgG enzyme immunoassays (EIA) from MRL Laboratories and PanBio, a rapid immunochromatographic test (RIT) from PanBio, immunofluorescence assays (IFA) from Progen, a dot blot assay from Genelabs, and a dipstick EIA from Integrated Diagnostics (INDX). For this study a panel of 132 serum samples, including 90 serum samples from patients with suspected dengue virus infection and 42 serum samples from patients with other viral infections, was used. In addition, serial serum samples from two monkeys experimentally immunized and challenged with dengue virus type 2 were used. Results were considered conclusive when concordant results were obtained with four of the six antibody-specific assays. Based on this definition, the calculated overall agreement for the human serum samples for the respective IgM immunoassays was 97% (128 of 132), with 34% (45 of 132) positive serum samples, 63% (83 of 132) negative samples, and 3% of samples (4 of 132) showing discordant results. The calculated overall agreement for the IgG assays was 94% (124 of 132), with 49% (65 of 132) positive, 45% (59 of 132) negative, and 6% (8 of 132) discordant results, respectively. The sensitivities of the dengue virus-specific assays evaluated varied between 71 and 100% for IgM and between 52 and 100% for IgG, with specificities of 86 to 96% and 8
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