Perceived stress management skill mediates the relationship between optimism and positive mood following radical prostatectomy.

This study evaluated relations among optimism, perceived stress management skills (PSMS), and positive mood in 46 men who had surgical treatment for localized prostate cancer. The authors found that optimism, PSMS, and positive mood scores were positively correlated. Positive mood was unrelated to demographic and disease-related control variables. In a hierarchical regression model controlling for PSMS, the relationship between optimism and positive mood became nonsignificant, whereas PSMS remained a correlate of positive mood. Results suggest that the relationship between optimism and positive mood may be mediated by belief in being able to use stress management techniques effectively. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ADI-FDTD Method With Fourth Order Accuracy in Time

This letter presents an unconditionally stable alternating direction implicit finite-difference time-domain (ADI-FDTD) method with fourth order accuracy in time. Analytical proof of unconditional stability and detailed analysis of numerical dispersion are presented. Compared to second order ADI-FDTD and six-steps SS-FDTD, the fourth order ADI-FDTD generally achieves lower phase velocity error for sufficiently fine mesh. Using finer mesh gridding also reduces the phase velocity error floor, which dictates the accuracy limit due to spatial discretization errors when the time step size is reduced further.     

Nonuniformity of phase structure in immiscible polymer blends

This article is focused on the phase structure development in immiscible polymer blends during melt mixing. Nonuniformity of the phase structure, i.e., the coexistence of areas containing particles with markedly different size distribution, was detected in quenched and compression molded samples of a number of various blends prepared by long and intensive mixing in the chamber of a Plasticorder. The same effect was found also for polystyrene/polyamide blends prepared in a twin‐screw extruder. It was shown that neglecting nonuniformity of the phase structure can lead to considerable error in evaluation of the effect of system parameters on the blend morphology. The reasons for the effect were discussed and it was found that inhomogeneous flow field in mixers is a plausible explanation of the nonuniform phase structure. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

A Surprise Party (on Your Computer)?

Iv?n Arce of Core Security Technologies looks at the current state of malware and introduces the articles he selected for this special issue.     

Perceived risk and trust associated with purchasing at electronic marketplaces

Understanding consumer behaviour is of vital importance to consumer-oriented e-business models today. In this paper, we study the relationships between consumer perceptions of risk and trust and the attitude towards purchasing at a consumer-to-consumer electronic marketplace (EM). Typical for EM settings is that consumer behaviour is subject to perceptions of the selling party as well as of the institutional structures of the intermediary that is operating the EM. Building upon the well-established literature of trust, we consider the concepts of intermediary trust and seller trust. We extend this categorisation by introducing the concepts of intermediary risk and seller risk. We developed measurement instruments for intermediary risk and seller risk. All measurement scales have acceptable alphas and are unidimensional. An empirical study is conducted to explore the relationships between the risk and trust types and consumer purchase attitude. The results reveal significant, direct effects of seller trust and seller risk. Second-order effects of intermediary trust and intermediary risk are investigated and reported. The paper concludes with general observations and recommendations for research and practice.     

新型超微晶软磁合金FePCCuMoSi微观结构缺陷的正电子湮没研究

用正电子湮没方法研究了新型超微晶软磁合金的微观结构缺陷，样品选用的是在不同温度下退火的Ｆｅ８１Ｐ１２Ｃ３Ｃｕ１Ｍｏ０．５Ｓｉ２．５合金，结果表明，合金的微观结构构陷大小，密度随退火温度有规律地变化，这种现象可能与非晶的晶化过程有关。     

重馏分油加氢脱氮反应动力学模型的研究

简要地介绍了一些典型的模型氮化物的ＨＤＮ反应规律。根据胜利ＶＧＯ在３７２２Ｂ催化剂上的大量ＨＤＮ实验数据，提出了如下的ＨＤＮ基本反应动力学方程：ｄＣＮｄｔ＝－ｋ１＋Ｋ＊ＣＮＣＮＰＨ２为了扩大上式的应用范围，详细分析了各种因素（如原料油种类和馏程及Ｈ２Ｓ等）对ＨＤＮ的影响，并开发了相应的经验关联式，从而得到了一个较完整的馏分油ＨＤＮ反应动力学模型。验证实验表明，该模型是成功的。     

Recursive optimal pruning with applications to tree structuredvector quantizers

A pruning algorithm of P.A. Chou et al. (1989) for designing optimal tree structures identifies only those codebooks which lie on the convex hull of the original codebook's operational distortion rate function. The authors introduce a modified version of the original algorithm, which identifies a large number of codebooks having minimum average distortion, under the constraint that, in each step, only modes having no descendents are removed from the tree. All codebooks generated by the original algorithm are also generated by this algorithm. The new algorithm generates a much larger number of codebooks in the middle- and low-rate regions. The additional codebooks permit operation near the codebook's operational distortion rate function without time sharing by choosing from the increased number of available bit rates. Despite the statistical mismatch which occurs when coding data outside the training sequence, these pruned codebooks retain their performance advantage over full search vector quantizers (VQs) for a large range of rates.