On the distribution of plasma L-asparaginase

Summary The guinea-pig,Cavia porcellus, is unusual in possessing plasma L-asparaginase, an enzyme with anti-tumor activity. 21 additional species have been examined as to the presence of this enzyme: the results confirm and extend its remarkably limited species distribution.This work was supported in part by grant GM/CA 25378 from the National Institute of General Medical Sciences, National Institutes of Health.We are grateful to dr Hanna Hensch, Philadelphia Zoological Garden, and Ms Joan Whitla and Dr Richard J. Montali, National Zoological Park/Smithsonian Institution, for samples of frozen serum.To whom correspondence should be addressed.     

On the distribution of plasma L-asparaginase

The guinea-pig, Cavia porcellus, is unusual in possessing plasma L-asparaginase, an enzyme with anti-tumor activity, 21 additional species have been examined as to the presence of this enzyme: the results confirm and extend its remarkably limited species distribution.     

Modeling and forecasting realized volatility in German–Austrian continuous intraday electricity prices

This paper uses high‐frequency continuous intraday electricity price data from the EPEX market to estimate and forecast realized volatility. Three different jump tests are used to break down the variation into jump and continuous components using quadratic variation theory. Several heterogeneous autoregressive models are then estimated for the logarithmic and standard deviation transformations. Generalized autoregressive conditional heteroskedasticity (GARCH) structures are included in the error terms of the models when evidence of conditional heteroskedasticity is found. Model selection is based on various out‐of‐sample criteria. Results show that decomposition of realized volatility is important for forecasting and that the decision whether to include GARCH‐type innovations might depend on the transformation selected. Finally, results are sensitive to the jump test used in the case of the standard deviation transformation.