Business Cycle Forecasts and their Implications for High Frequency Stock Market Returns

This article contributes to the literature on business cycle forecasts and their impact on asset prices by investigating how the 15‐second Xetra DAX returns reflect the monthly announcements of the two best‐known business cycle forecasts for Germany, i.e., the Ifo Business Climate Index and the ZEW Indicator of Economic Sentiment. The analysis disentangles ‘good’ macroeconomics news from ‘bad’ news and, simultaneously, considers time intervals with and without confounding announcements from other sources. Releases from both institutes lead to an immediate response of returns occurring 15 seconds after the announcements, i.e. within the first possible time interval. Announcements of both institutes are also clearly and immediately reflected in the volatility, which remains at a significantly higher level for approximately 2 minutes. Findings can be used to improve high‐frequency forecasts in stock markets. Copyright © 2011 John Wiley & Sons, Ltd.     

Inhibition of cholesterol recycling impairs cellular PrPSc propagation

The infectious agent in prion diseases consists of an aberrantly folded isoform of the cellular prion protein (PrP^c), termed PrP^Sc, which accumulates in brains of affected individuals. Studies on prion-infected cultured cells indicate that cellular cholesterol homeostasis influences PrP^Sc propagation. Here, we demonstrate that the cellular PrP^Sc content decreases upon accumulation of cholesterol in late endosomes, as induced by NPC-1 knock-down or treatment with U18666A. PrP^c trafficking, lipid raft association, and membrane turnover are not significantly altered by such treatments. Cellular PrP^Sc formation is not impaired, suggesting that PrP^Sc degradation is increased by intracellular cholesterol accumulation. Interestingly, PrP^Sc propagation in U18666A-treated cells was partially restored by overexpression of rab 9, which causes redistribution of cholesterol and possibly of PrP^Sc to the trans-Golgi network. Surprisingly, rab 9 overexpression itself reduced cellular PrP^Sc content, indicating that PrP^Sc production is highly sensitive to alterations in dynamics of vesicle trafficking.     

饱和岩层中地下水渗流与岩体变形的耦合数学模型及数值解法

地压作用下岩体、水等多相介质相互作用与组合运动规律是岩土工程界目前面临的难题 .根据固体和流体耦合作用的基本理论 ,考虑水对岩体本构关系的影响 ,提出了岩体和水耦合作用的数学模型 .在此基础上 ,对地下采动影响下考虑饱水岩体变形影响时水的流动规律进行了数值模拟分析 ,为地下岩体开挖时 ,对地下水的控制提供了理论基础和科学依据 .图 3,参 5 .     

多笔画联机手写字符识别的动态时间规正算法

在单笔画符号(或字符)联机手写识别中,动态时间规正(DTW)算法遵循时间次序约束和边界约束,并具有较高的识别率.为了将此算法应用于多笔画符号识别,常用而简单的方法是按照人们的手写顺序连接多笔画符号为单笔画符号.但此方法存在一个问题:人们常使用不同的笔画顺序和笔画方向书写同一个符号,用朴素(Brute Force)方法寻找所有笔画可能性非常耗时.为了降低计算复杂度,文中提出了DTW A*算法.在部分笔画匹配时,此算法保留着次序约束,并用A*算法降低计算复杂度.文中还通过流程图数据库多笔画符号识别实验对比了DTW A*算法、DTW算法、改良Hausdorff距离3种算法的性能,结果表明DTW A*算法具有最高的识别率和最好的稳定性.     

Pivotal role of oligomerization in expanded polyglutamine neurodegenerative disorders

The expansion of a CAG repeat coding for polyglutamine in otherwise unrelated gene products is central to eight neurodegenerative disorders including Huntington's disease. It has been well documented that expanded polyglutamine fragments, cleaved from their respective full-length proteins, form microscopically visible aggregates in affected individuals and in transgenic mice. The contribution of polyglutamine oligomers to neurodegeneration, however, is controversial. The azo-dye Congo red binds preferentially to beta-sheets containing amyloid fibrils and can specifically inhibit oligomerization and disrupt preformed oligomers. Here we show that inhibition of polyglutamine oligomerization by Congo red prevents ATP depletion and caspase activation, preserves normal cellular protein synthesis and degradation functions, and promotes the clearance of expanded polyglutamine repeats in vivo and in vitro. Infusion of Congo red into a transgenic mouse model of Huntington's disease, well after the onset of symptoms, promotes the clearance of expanded repeats in vivo and exerts marked protective effects on survival, weight loss and motor function. We conclude that oligomerization is a crucial determinant in the biochemical properties of expanded polyglutamine that are central to their chronic cytotoxicity.     

Geochemical evidence for efficient aquifer isolation over geological timeframes

Aquitards-layers of rock having low permeability-have been suggested as potential long-term reservoirs for toxic materials such as nuclear or chemical waste. But information about the isolation properties of aquitard layers is essential to evaluate whether they can indeed be used safely as reservoirs. Here we investigate the long-term mobility of groundwaters between two aquifers surrounding an aquitard layer in the eastern recharge area of the Paris basin, France, using helium isotopes as a geochemical tracer. The deeper Trias sandstone aquifer, which lies above the crystalline basement, accumulates radiogenic (4)He and primordial (3)He from large regions of the crust and mantle at rates comparable to the degassing of the whole crust and of mid-ocean ridges. We show that the overlying carbonate Dogger aquifer, which is separated from the Trias aquifer by an aquitard layer consisting of a approximately 600 m succession of shales and clays, is stagnant and has been extremely well isolated from the Trias over the past several million years. This finding, together with previous studies at the centre of the Paris basin, shows that diffusive mass transfer across aquitards is negligible and that cross-formational flow in basins takes place preferentially in faulted areas.     

Permian tetrapods from the Sahara show climate-controlled endemism in Pangaea

New fossils from the Upper Permian Moradi Formation of northern Niger provide an insight into the faunas that inhabited low-latitude, xeric environments near the end of the Palaeozoic era (approximately 251 million years ago). We describe here two new temnospondyl amphibians, the cochleosaurid Nigerpeton ricqlesi gen. et sp. nov. and the stem edopoid Saharastega moradiensis gen. et sp. nov., as relicts of Carboniferous lineages that diverged 40-90 million years earlier. Coupled with a scarcity of therapsids, the new finds suggest that faunas from the poorly sampled xeric belt that straddled the Equator during the Permian period differed markedly from well-sampled faunas that dominated tropical-to-temperate zones to the north and south. Our results show that long-standing theories of Late Permian faunal homogeneity are probably oversimplified as the result of uneven latitudinal sampling.