Price–Dividend Ratios and Stock Price Predictability

A long‐standing puzzle to financial economists is the difficulty of outperforming the benchmark random walk model in out‐of‐sample contests. Using data from the USA over the period of 1872–2007, this paper re‐examines the out‐of‐sample predictability of real stock prices based on price–dividend (PD) ratios. The current research focuses on the significance of the time‐varying mean and nonlinear dynamics of PD ratios in the empirical analysis. Empirical results support the proposed nonlinear model of the PD ratio and the stationarity of the trend‐adjusted PD ratio. Furthermore, this paper rejects the non‐predictability hypothesis of stock prices statistically based on in‐ and out‐of‐sample tests and economically based on the criteria of expected real return per unit of risk. Copyright © 2011 John Wiley & Sons, Ltd.     

Acrylamide from Maillard reaction products

The discovery of the adventitious formation of the potential cancer-causing agent acrylamide in a variety of foods during cooking has raised much concern, but the chemical mechanism(s) governing its production are unclear. Here we show that acrylamide can be released by the thermal treatment of certain amino acids (asparagine, for example), particularly in combination with reducing sugars, and of early Maillard reaction products (N-glycosides). Our findings indicate that the Maillard-driven generation of flavour and colour in thermally processed foods can -- under particular conditions -- be linked to the formation of acrylamide.     

Observation of coherent optical information storage in an atomic medium using halted light pulses

Electromagnetically induced transparency is a quantum interference effect that permits the propagation of light through an otherwise opaque atomic medium; a 'coupling' laser is used to create the interference necessary to allow the transmission of resonant pulses from a 'probe' laser. This technique has been used to slow and spatially compress light pulses by seven orders of magnitude, resulting in their complete localization and containment within an atomic cloud. Here we use electromagnetically induced transparency to bring laser pulses to a complete stop in a magnetically trapped, cold cloud of sodium atoms. Within the spatially localized pulse region, the atoms are in a superposition state determined by the amplitudes and phases of the coupling and probe laser fields. Upon sudden turn-off of the coupling laser, the compressed probe pulse is effectively stopped; coherent information initially contained in the laser fields is 'frozen' in the atomic medium for up to 1 ms. The coupling laser is turned back on at a later time and the probe pulse is regenerated: the stored coherence is read out and transferred back into the radiation field. We present a theoretical model that reveals that the system is self-adjusting to minimize dissipative loss during the 'read' and 'write' operations. We anticipate applications of this phenomenon for quantum information processing.     

胶子自作用对胶子球能量的修正

本文在零级近似的基础上，考虑胶子自作用对胶子球能量的修正．     

OFDM系统中改进的FFT插值算法

提出了一种基于快速傅立叶变换的边缘扩展信道插值算法（EFFT,Edged Extend Fast Fourier Transform）。该算法对OFDM符号有效频带边缘的两端频点做镜像线性扩展,使增加的导频信息能改善有效频带边缘附近的信道估计性能。仿真结果表明,在低阶调制且SNR较低时,EFFT插值算法的性能与维纳滤波信道估计算法相当,且较传统FFT插值算法的MSE提升1dB左右。在实现复杂度方面,EFFT算法与FFT算法相当;与维纳滤波算法相比运算量明显降低。EFFT算法不需要对现有技术标准进行改动,也不会降低系统的传输效率。     

高聚物在簿模腔中流动及传热研究

针对熔融高聚物进入壁温低于高聚物固化温度的模腔中，被迅速冷却而形成固化层的现象，采用有限元法对高聚物在薄模腔中的流动，及伴有固化现象的传热进行模拟，并进行实验研究和验证．计算及实测结果一致．     

浅谈控制项目成本提高经济效益

阐述了公路施工全过程、全方面对人工费、村料费、机械费、结算的成本控制,以此达到最好的经济效益.     

原子核体系能级综合模型的解析解

基于对原子核定态能级实验事实进行分析,通过单核子在平均自洽场中独立运动模型,将壳层模型汤川秀树势和伍德萨松势分析模拟,建立汤川-伍德-萨松-势(Y-W-S-P).并结合液滴模型势能的特性,魏扎克(C.F.Weizsacker)公式建立综合模型势,同时建立了相应的定态薛定谔方程.应用泰勒微扰法和类氢原子能量表象的径向矩阵元的精要形式,求得一级微扰能和零级能,导出了原子核能级精细结构解,其结果与实验值有可比性.     

中长期预测模型的GMDH两水平算法的改进及实证分析比较

两水平算法是以自组织原理为基础应用多层迭代、采用季节数据和年数据同时建模 ,在一定程度上扩大可预测范围 .主要用于复杂系统建模 .对算法作改进 ,使模型在对具有周期趋势的事物预测更加准确 .实证分析表明 ,对算法改进有效 .