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.     

Glucocorticoids and aging

In this review we analyze the morphologic changes, hypothalamic-pituitary-adrenal (HPA) axis functions, glucocorticoid (GC) receptors, and steroidogenic enzyme activities in both animals and humans during aging. In rodent studies, older animals tend to show: 1) hypertrophy of adrenal zona fasciculata (ZF) cells; 2) neuronal loss in the hypothalamic area; 3) loss of GC receptors in the hippocampus; 4) raised circulating adrenocorticotropic hormone (ACTH) and GC levels, and increased release of corticotropin-releasing hormone from the hypothalamus; 5) reduced suppression of endogenous GC secretion after administration of dexamethasone; 6) decreased attenuation of response to chronic stress; and 7) increased activity of P450scc and 21-hydroxylase. According to the GC cascade hypothesis, stress and GCs facilitate the aging process in rats. Stress induces downregulation of GC receptors in the hippocampus, then impairs GC feedback on stress-induced HPA axis activation. Finally, an increase in the basal level of corticosterone and extended GC secretion following stress occurs. Because activation of the hippocampus decreases HPA axis function, the unrestrained elevation of GC concentration and the reduction in the level of GC receptors in the hippocampus may gradually weaken the feedback mechanisms and halt the response to stress. In humans, there are conflicting reports of HPA axis function during aging, so it is difficult to make a final conclusion regarding the relationship between aging and HPA axis function.     

The new parameters of motor unit potential in the diagnosis of neurogenic lesions in spike-triggered averaging electromyography

The chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) is characterized by a pronounced antibody response and microcolonies surrounded by numerous polymorphonuclear neutrophils (PMN). Poor prognosis is correlated with a high antibody response to P. aeruginosa antigens. An animal model of this infection was established in two strains of mice: C3H/HeN and BALB/c, generally known as Th1 and Th2 responders, respectively, which were challenged with alginate-embedded P. aeruginosa. Mortality was significantly lower in C3H/HeN compared to BALB/c mice (p < 0.025). P. aeruginosa was cleared more efficiently in C3H/HeN mice and significantly more C3H/HeN mice showed normal lung histopathology (p < 0.02), and we found significantly fewer microabscesses in C3H/HeN mice than in BALB/c mice (p < 0.005). In supernatants from P. aeruginosa antigen and concanavalin A-stimulated spleen cells from the two strains of mice, the interferon-(IFN-) gamma levels were higher, whereas IL-4 levels were lower in C3H/HeN mice than in BALB/c mice. The implications of these findings for CF patients with chronic P. aeruginosa lung infection are discussed.     

Fast adders using enhanced multiple-output domino logic

Using an enhanced multiple output domino logic (EMODL) implementation of a carry lookahead adder (CLA), sums of several consecutive bits can be built in one nFET tree with a single carry-in. Based on this result, a new sparse carry chain architecture is proposed for the CLA adder. We demonstrate the design approach using a 32-b adder, and show that only four carries are sufficient for generating all sums, with a consequent reduction in the number of stage delays. Using a 1.2-μm CMOS technology, we verify our simulation procedures by fabrication and measurement of a 2.7 ns critical path     

Study on Hot Deformation Cracks of Steel D2 Using Procesing Map

ＳｔｕｄｙｏｎＨｏｔＤｅｆｏｒｍａｔｉｏｎＣｒａｃｋｓｏｆＳｔｅｅｌＤ２ＵｓｉｎｇＰｒｏｃｅｓｉｎｇＭａｐＧａｏＳｈａｎ，ＬｉｕＸｉａｎｇｈｕａ，ＷａｎｇＧｕｏｄｏｎｇＡＢＳＴＲＡＣＴＴｈｅｈｏｔｄｅｆｏｒｍａｔｉｏｎｂｅｈａｖｉｏｒｓｏｆｓｔｅｅｌ...     

铝钛双金属板KR曲线测定

利用宽３００ｍｍ、长／宽＝１的横向ＣＴＴ试样对国产铝钛双金属板做了常规力学性能测定，并按航标测定了ＫＲ曲线，经过柔度法和Ｋ值计算，分别测得了ＫＲｉ和ａｉ数据，确定了临界的ＫＣ值通过性能数据对比，研制的材料达到了进口料的性能要求。     

Efficiency improvement in charge pump circuits

Conventional charge pump circuits use a fixed switching frequency that leads to power efficiency degradation for loading less than the rated loading. This paper proposes a level shifter design that also functions as a frequency converter to automatically vary the switching frequency of a dual charge pump circuit according to the loading. The switching frequency is designed to be 25 kHz with 12 mA loading on both inverting and noninverting outputs. The switching frequency is automatically reduced when loading is lighter to improve the power efficiency. The frequency tuning range of this circuit is designed to be from 100 Hz to 25 kHz. A start-up circuit is included to ensure proper pumping action and avoid latch-up during power-up. A slow turn-on, fast turn-off driving scheme is used in the clock buffer to reduce power dissipation. The new dual charge pump circuit was fabricated in a 3-μm p-well double-poly single-metal CMOS technology with breakdown voltage of 18 V, the die size is 4.7×4.5 mm². For comparison, a charge pump circuit with conventional level shifter and clock buffer was also fabricated. The measured results show that the new charge pump has two advantages: (1) the power dissipation of the charge pump is improved by a factor of 32 at no load and by 2% at rated loading of 500 Ω and (2) the breakdown voltage requirement is reduced from 19.2 to 17 V     

液罐汽车转弯制动稳定性的研究

该文研究罐装部分液体汽车在转弯制动工况下，由于液体货物质心位置的变化对行驶稳 定性的影响。文中建立了有关力学模型和数学模型，分析研究了罐体内装载不同量液体对汽车转弯制动时横摆角速度的影响规律。     

本钢炼焦煤最佳配比分析

结合本钢的生产实际，对炼焦煤的最佳配比作了比较具体的分析，同时对资源，质量、成本也作了比较详细的调查，并提出了本钢焦化厂最佳配煤比方案，由此可看出，最大限度地降低采购成本，继续开发合理的配煤比例，具有广阔的前景。     

论BFe30—1—1冷凝管生产工艺及其改进的途径

论述了ＢＥｅ３０－１－１冷凝管生产工艺的优点及主要问题，对现行工艺提出了改进方案。