Structural econometric modeling and time series analysis

We discuss the Structural Econometric Modeling and Time Series Analysis (SEMTSA) approach put forward by Zellner and Palm, which provides a synthesis of econometric and time series methods in modeling economic time series. The approach aims at giving guidance for checking the data admissibility of the dynamic specification of a model in its various forms, in particular the transfer function form and the final equation form. We review the SEMTSA approach, discuss recent developments, and briefly compare the SEMTSA with other methodologies for econometric modeling. Finally some remarks are made about problems that remain to be solved.     

Thermal convection in a rotating porous layer

Summary It is found in this note that basic results concerning thermal convection in a rotating porous layer may be obtained from known analysis of thermal convection in an (non-rotating) anisotropic porous medium.

---

Résumé On peut obtenir des résultats de base sur la convection thermique dans une couche poreuse en rotation à partir de l'analyse connue de la convection thermique dans une couche poreuse anisotrope pas en rotation.

     

More Sub-Doppler Heterodyne Frequency Measurements on OCS between 56 and 63 THz

By using tunable microwave sidebands added to CO-laser lines, we have made more sub-Doppler heterodyne frequency measurements on OCS. Three new rotational transitions have been measured for each of three absorption bands, 10(0)0-00(0)0, 02(0)1-00(0)0, and 03(1)1-01(1)0. The absolute uncertainties of the measurements are on the order of +/-25 kHz. New calibration tables are given for the region 1860-1925 and 2020-2085 cm(-1) based on the most recent OCS measurements. Copyright 2000 Academic Press.     

Sequence‐Based Prediction of Promiscuous Acyltransferase Activity in Hydrolases

Certain hydrolases preferentially catalyze acyl transfer over hydrolysis in an aqueous environment. However, the molecular and structural reasons for this phenomenon are still unclear. Herein, we provide evidence that acyltransferase activity in esterases highly correlates with the hydrophobicity of the substrate‐binding pocket. A hydrophobicity scoring system developed in this work allows accurate prediction of promiscuous acyltransferase activity solely from the amino acid sequence of the cap domain. This concept was experimentally verified by systematic investigation of several homologous esterases, leading to the discovery of five novel promiscuous acyltransferases. We also developed a simple yet versatile colorimetric assay for rapid characterization of novel acyltransferases. This study demonstrates that promiscuous acyltransferase activity is not as rare as previously thought and provides access to a vast number of novel acyltransferases with diverse substrate specificity and potential applications.