Effects of different physical workload parameters on mental workload and performance

The design and evaluation of an occupational task should include an assessment of mental workload, since excessive levels of mental workload can cause errors or delayed information processing. Physically demanding work that is performed concurrently with a cognitive task may impact mental workload by impairing mental processing or decreasing performance. The primary objective of this study was to determine whether there is a differential effect of various types of physical activity on both mental workload and cognitive performance. Objective and subjective assessment tools (heart rate variability and visual analog scale) were used as indicators of mental workload, while correct responses during an arithmetic task reflected levels of performance. Thirty participants (ages 18-24 years) performed a combination of tasks inducing both physical and mental workload. Type of physical effort, frequency of movement, and force exertion level were manipulated to alter the workload associated with the physical activity. Changes in subjective ratings generally corresponded to changes in both performance on the arithmetic task and objective mental workload assessment. Some discrepancies occurred at the highest physical force exertion level as participants perceived an increase in effort to maintain the same level of performance. Further research is needed to determine the force exertion threshold, beyond which the physical effort required interferes with mental workload and/or cognitive performance.

Relevance to industry

Technological advancements have increased the requirement for many workers to execute cognitive tasks concurrently with physical activity. When designing and evaluating such situations it is important to determine the interactive effects of these activities. A simple, uni-dimensional tool is suggested as a screening tool to identify situations requiring excessive or increased mental workload that many degrade performance or place additional stress on the individual.     

Stability of Individual Phenolic Compounds and Antioxidant Activity During Storage of a Red Wine Powder

The addition of maltodextrin DE 10 to red wine (Cabernet Sauvignon) followed by freeze-drying allowed to obtain a free-flowing (dealcoholized) wine powder (WP) having a phenolic concentration about 3.6 times higher than the original liquid red wine. The powder, having a water activity (a _w) of 0.053 and 0.330 was stored at 28 °C and 38 °C and the content of ten different phenolic compounds was determined by HPLC. Caftaric acid, quercetin 3-glucoside, caffeic acid, gallic acid and resveratrol contents in the WP stored at 28 °C and 38 °C, remained almost constant during 70 days of storage, while epicatechin gallate, catechin, malvidin 3-G and epicatechin showed slight losses (about 15–25 %) during storage. On the contrary, epigallocatechin experienced a strong loss of concentration (around 61 % loss) during storage at the same conditions. A moderate decrease of antioxidant activity, determined by free radical scavenging capacity of the 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH*) and ferric reducing antioxidant power (FRAP) was observed along storage. This decrease was more important at higher temperature (38 °C) and higher a _w (0.33). These results would allow the feasibility of using this WP as a healthy ingredient in alcohol-free powder drinks.     

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Low-Cost All-Optical Up-Conversion of Digital Radio Signals Using a Directly Modulated 1550-nm Emitting VCSEL

The purpose of this letter is to demonstrate the extension of the modulation bandwidth of a single-mode vertical-cavity surface-emitting laser (VCSEL). The aim is to reach the radio-frequency range of wireless access networks such as ultrawide-band systems with low-cost solutions. In this letter, we have studied optical microwave mixing using nonlinear direct modulation of a VCSEL. First, the nonlinear behavior of the VCSEL near the threshold has been analyzed and explained based on frequency-mixing measurements made with continuous-wave signals. Then, we have experimentally demonstrated frequency up-conversion of a quaternary phase-shift-keying signal and a wireless local area network IEEE 802.11a signal.     

Embedded layer of Ag nanoparticles prepared by a combined PECVD/PVD process producing SiOxCy-Ag nanocomposite thin films

Structural properties of SiO(x)C(y)-Ag nanocomposite thin films prepared by a dual process PVD-PECVD in the same reactor have been investigated. The experimental results have demonstrated the influence of a PECVD process carried out at room temperature for the growth of a dielectric matrix on the size and the distribution density of Ag nanoparticles (NPs) deposited beforehand by magnetron sputtering. The plasma during the growth of the encapsulation SiO(x)C(y) layer caused a diffusion of silver from NPs through the SiO(x)C(y) matrix associated with a decrease in the average size of nanoparticles and an increase of their distribution density. Silver diffusion is blocked at a barrier interface to form a buried layer of individual Ag NPs which, for instance, can find plasmonic applications. Silver also diffuses toward the outer surface inducing antibacterial properties. In both cases initial Ag NPs act as reservoirs for multifunctional properties of advanced nanostructured films.     

Efficient Path-Space Differentiable Volume Rendering With Respect To Shapes

Differentiable rendering of translucent objects with respect to their shapes has been a long-standing problem. State-of-the-art methods require detecting object silhouettes or specifying change rates inside translucent objects—both of which can be expensive for translucent objects with complex shapes. In this paper, we address this problem for translucent objects with no refractive or reflective boundaries. By reparameterizing interior components of differential path integrals, our new formulation does not require change rates to be specified in the interior of objects. Further, we introduce new Monte Carlo estimators based on this formulation that do not require explicit detection of object silhouettes.     

手机无线电：不再只是电话功能

在美国加州圣迭戈市Demo Fall大会上(2006年9月26日～27日)最吸引人的产品和演示都集中在手机连接方面.也许这种关注不应让我惊讶,因为这次秋季会议的名称就是Demo Mobile(手机演示).但这次的手机有所不同.会议的特色是带摄像头和其它传感器的手机,它们用于增强基本的电话功能.但最引人注目的概念则是将集成的手机无线电用作另一种使能部件.     

网络传送

Windows驱动的低功耗PC设计能够通过互联网传送视频节目,但传送内容是成功的关键。Akimbo是第一款真正能提供PVR(个人录像机)式体验的消费产品,尽管它要使用宽带互联网连接,产品性能良好,但内容的选择可能会局限其取得成功的程度。     

John P. Sabini (1947-2005).

Presents an obituary for John Paulus Sabini. Sabini spent his career, starting in 1976, in the Department of Psychology at the University of Pennsylvania. Sabini was fascinated with Milgram's research on obedience. Milgram's imprint is obvious in Sabini's interest in social influence, the psychology of everyday life, and in his style. Sabini's studies of moral reproach, gossip, procrastination, embarrassment, envy, shame, self-deception, and sincerity are simultaneously analyses of causal determinants and of speech acts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)