A New‐Keynesian DSGE model for forecasting the South African economy

This paper develops a New‐Keynesian Dynamic Stochastic General Equilibrium (NKDSGE) model for forecasting the growth rate of output, inflation, and the nominal short‐term interest rate (91 days Treasury Bill rate) for the South African economy. The model is estimated via maximum likelihood technique for quarterly data over the period of 1970:1–2000:4. Based on a recursive estimation using the Kalman filter algorithm, out‐of‐sample forecasts from the NKDSGE model are compared with forecasts generated from the classical and Bayesian variants of vector autoregression (VAR) models for the period 2001:1–2006:4. The results indicate that in terms of out‐of‐sample forecasting, the NKDSGE model outperforms both the classical and Bayesian VARs for inflation, but not for output growth and nominal short‐term interest rate. However, differences in RMSEs are not significant across the models. Copyright © 2008 John Wiley & Sons, Ltd.     

基于布谷鸟搜索算法参数优化的组合核极限学习机

针对单核极限学习机在泛化性能上存在一定局限性的问题, 提出将再生核函数与多项式核函数相结合, 建立一种新的组合核极限学习机模型, 使其具有全局核与局部核的优点, 并选择布谷鸟搜索算法对其参数进行优化选择. 仿真实验结果表明, 采用基于再生核的组合核函数作为极限学习机的核函数可行, 在实验数据集的多值分类和回归问题上, 与传统支持向量机及单核极限学习机相比, 该模型具有更好的泛化性能.     

高速公路入口匝道汇合控制下的道路通行能力

研究了高速公路入口匝道实行汇合控制下的通行能力，在以往的研究中通常把可接受间隙作为一个固定参数进行计算，在本文中，则把可接受间隙作为一个概率分布来研究，同时本研究根据主线车流车头时距分布，给出了各级服务水平下道路通行能力的计算公式，并给出了仿真结果。     

Paleomagnetic data from Early Cretaceous volcanic rocks of West Liaoning: Evidence for intracontinental rotation

Detailed rock magnetic studies of 55 lavas from Yixian and Fuxin area, West Liaoning, show the primary carriers of remanence to be pseudo-single domain titanomagnetite. K/Ar dating indicates that the volcanic sequence spans 93 to 133 Ma. Stepwise thermal demagnetization successfully isolated well-defined characteristic magnetization (ChRM) in all lavas thermal-treated above 250℃. The mean paleodirections are D/I = 5.9°/58.8° (α95 = 2.9°) and D/I =179.2°/-59.9° (α95 = 5.2°) for 27 normally magnetized flows and 28 reversibly magnetized flows, respectively. It indicates that since the Early Cretaceous there is no significant horizontal movement and rotation between the Yixian-Fuxin area and Eurasia. However, Korea Peninsula may have undergone a clockwise rotation of 33.9° relative to the Yixian-Fuxin area during the Cretaceous. On the basis of characteristics of hotspot origins (core-mantle boundary or upper mantle), the clockwise rotation of Korea Peninsula relative to Eurasia is assumed to be mainly caused by an extensional force in the crust of eastern China, which was corresponding to intensive surface volcanic activities in this area.     

A complete sequence and comparative analysis of a SARS-associated virus （Isolate BJO1）

The genome sequence of the Severe Acute Respiratory Syndrome (SARS)-assoclated virus provides essential information for the identification of pathogen(s), exploration of etiology and evolution, interpretation of transmission and pathogenesis, development of diagnostics, prevention by future vaccination, and treatment by developing new drugs.We report the complete genome sequence and comparative analysis of an isolate (B J01) of the coronavirus that has been recognized as a pathogen for SARS. The genome is 29725 nt in size and has 11 ORFs (Open Reading Frames). It is composed of a stable region encoding an RNA-dependent RNA polymerase (composed of 20RFs) and a variable region representing 4 CDSs (coding sequences) for viral structural genes (the S, E, M, N proteins) and 5 PUPs (putative uncharacterized proteins). Its gene order is identical to that of other known coronaviruses. The sequence alignment with all known RNA viruses places this virus as a member in the family of Coronaviridae. Thirty putative substitutions have been identified by comparative analysis of the 5 SARS-associated virus genome sequences in GenBank. Fifteen of them lead to possible amino acid changes (non-synonymous mutations) in the proteins. Three amino acid changes, with predicted alteration of physical and chemical features, have been detected in the S protein that is postulated to be involved in the immunoreactions between the virus and its host.Two amino acid changes have been detected in the M protein,which could be related to viral envelope formation. Phylogenetic analysis suggests the possibility of non-human origin of the SARS-associated viruses but provides no evidence that they are man-made. Further efforts should focus on identifying the etiology of the SARS-associated virus and ruling out conclusively the existence of other possible SARS-related pathogen(s).     

A combined study of SHRIMP U-Pb dating, trace element and mineral inclusions on high-pressure metamorphic overgrowth zircon in eclogite from Qinglongshan in the Sulu terrane

Methods recently advanced for discrimination on the genesis of metamorphic zircon, such as analysis of mineral inclusions and trace elements, provide us powerful means to distinguish zircon overgrowth during high-pressure metamorphism. Zircons in ultrahigh-pressure eclogite from Qinglongshan in the Sulu terrane were studied by the SHRIMP U-Pb method in combining with trace element and mineral inclusion analyses. No inherited core was identified in the analyzed zircons by means of cathodoluminescence images. The occurrence of high-pressure metamorphic mineral inclusions in zircon, such as garnet, omphacite, rutile, and the flat HREE pattern in zircon indicate that the zircon formed at high-pressure metamorphic conditions. Therefore, a weighted average U-Pb age of 227.4±3.5 Ma obtained from such a kind of zircon is interpreted to represent the timing of peak nietamorphism for the Qinglongshan eclogite.     

The abnormal sensitivity and its mechanism of （Ba, Pb）TiO3 semiconductor ceramics

The resistance-temperature properties of porous (Ba, Pb)TiO3 semiconductor ceramic were systematically studied. It was found that the resistance of (Ba, Pb)TiO3 ceramic having been placed in the air for a long time was abnormally increased with the increase of the temperature from the room temperature to 70℃ prior to the Curie point. Further research showed that this abnormal resistance-temperature property was linked to its humidity sensitivity. When the relative humidity changed from 11% to 93%, the resistance of (Ba, Pb)TiO3 ceramic decreased three orders of magnitude. Furthermore, the humidity-resistance was approximately linear in single logarithm coordinate. According to the surface adsorption, grain-boundary potential barrier and ferroelectric-paraelectric phase transformation, the specific sensitive mechanism of (Ba, Pb)TiO3 ceramic was analyzed qualitatively.     

Involvement of the crebellum in sequential finger movement learning： Evidence from functional magnetic resonance imaging

Whether the cerebellum is involved in voluntary motor learning or motor performance is the subject of a new debate. Using functional magnetic resonance imaging （fMRI）, we examined cerebellar activation in eight voluntecrs before and after an extended period of training. Activation volume on both sides of cerebellum after learning was significantly reduced compared to that before learning even under the same motor frequency. Remarkably, while motor frequency for the training sequence was significantly higher than the control sequence after 41 d of learning, activation in the cerebellum for both sequences, with respect to activation loci and volumes, was very similar. These results suggest that the cerebellum was involved in motor learning but not motor performance. Changes of cerebellar activation from training thus appear to be associated with learning but not with improvement on task performance.