The effects of vitamin E and selenium intake on oxidative stress and plasma lipids in hamsters fed fish oil

The aim of the present work was to test the effects of large-dose supplementation of vitamin E (Vit E) and selenium (Se), either singly or in combination, on fish oil (FO)-induced tissue lipid peroxidation and hyperlipidemia. The supplementation of Se has been shown to lower blood cholesterol and increase tissue concentrations of the antioxidant glutathione (GSH); however, the effects of Se supplementation, either alone or in combination with supplemental Vit E, on FO-induced oxidative stress and hyperlipidemia have not been studied. Male Syrian hamsters received FO-based diets that contained 14.3 wt% fat and 0.46 wt% cholesterol supplemented with Vit E (129 IU d-α-tocopheryl acetate/kg diet) and/or Se (3.4 ppm as sodium selenate) or that contained basal requirements of both nutrients. The cardiac tissue of hamsters fed supplemental Se showed increased concentrations of lipid hydroperoxides (LPO) but decreased oxidized glutathione (GSSG) concentrations. The higher concentrations of LPO in the hearts of Se-supplemented hamsters were not lowered with concurrent Vit E supplementation. In the liver, Se supplementation was associated with higher Se-dependent glutathione peroxidase activity and an increase in the GSH/GSSG ratio, whereas a lower hepatic non-Se-dependent glutathione peroxidase activity was seen with Vit E supplementation. Supplemental intake of Se was associated with lower plasma concentrations of total cholesterol and low density lipoprotein cholesterol plus very low density lipoprotein cholesterol. In view of the pro-oxidative effects of Se supplementation on cardiac tissue, a cautionary approach needs to be taken regarding the plasma lipid-lowering properties of supplemental Se.     

Laser projection versus a CRT display in the visual perception of aircraft aspect

High-resolution visual displays have been designed for flight simulation so that observers may judge the aspect angle of aircraft at far distances. The present experiment compares two display devices as untrained observers judge the spatial orientation of two target aircraft: F-15 and F-16 jets. The display devices are a prototype direct-write microlaser projector and an SXGA-format CRT display. Observers' accuracy of aircraft identification is better with the laser projector, and recognition response times are faster. A simple rule was found to fit the observers' response times; it is expressed in terms of a statistic on the autocorrelation of black-and-white silhouette images of aircraft. Observers' estimates of aspect are biased by the laser projector, whereas observers' estimates of aspect are accurate on average with the SXGA display. This bias in estimation of aspect may be attributable to variations in line brightness introduced by the laser projector. Actual or potential applications of this research include the evaluation of high-resolution visual displays for the training of basic fighter maneuvers with military jet pilots.     

Efficacy of a tailored tobacco control program on long-term use in a population of U.S. Military troops.

The authors evaluated the effect of a brief tailored smoking control intervention delivered during basic military training on tobacco use in a population of military personnel (N = 33,215). Participants were randomized to either a tobacco use intervention (smoking cessation, smokeless tobacco use cessation, or prevention depending on tobacco use history) or a health education control condition. Results indicated that smokers who received intervention were 1.16 (95% confidence interval [CI] = 1.04, 1.30) times (7-day point prevalence) and 1.23 (95% CI = 1.07, 1.41) times (continuous abstinence) more likely to be abstinent than controls from smoking cigarettes at the 1-year follow-up (p p     

Age-related binding deficits and the content of false memories.

The authors examined effects of age-related binding deficits on feature information in false memories for imagined objects (e.g., lollipop) that were similar in shape to seen objects (e.g., magnifying glass). In Experiment 1, location memory for seen objects was lower in older than younger adults and lower still in old-old than young-old adults. Imagined objects, when falsely called seen, were less likely to be attributed to the location of similar seen objects (i.e., congruent attributions) by old-old than young-old adults. In Experiment 2, for younger adults, displaying seen objects for less time (1 s vs. 4 s) reduced both location memory for seen objects and congruent attributions for false memories. Thus, binding deficits may influence the specific content of false memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Starting low but ending high: A reversal of the anchoring effect in auctions.

Counter to the "start high, end high" effect of anchors in individual judgments and dyadic negotiations, 6 studies using a diverse set of methodologies document how and why, in the social setting of auctions, lower starting prices result in higher final prices. Three processes contribute to this effect. First, lower starting prices reduce barriers to entry, which increase traffic and generate higher final prices. Second, lower starting prices entice bidders to invest time and energy (creating sunk costs) and, consequently, escalate their commitments. Third, the traffic generated by lower starting prices can lead bidders to infer value in the item, thereby explaining previous findings that traffic begets more traffic. The authors show that barriers to entry that limit traffic (e.g., a misspelled brand name) lead to anchoring's normal assimilative effect rather than its reversal. By broadening the understanding of anchors to extended social interactions and open markets, the authors identify when and why starting prices anchor. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High-maintenance interaction: Inefficient social coordination impairs self-regulation.

Tasks requiring interpersonal coordination permeate all spheres of life. Although social coordination is sometimes efficient and effortless (low maintenance), at other times it is inefficient and effortful (high maintenance). Across 5 studies, participants experienced either a high- or a low-maintenance interaction with a confederate before engaging in an individual-level task requiring self-regulation. Self-regulation was operationalized with measures of (a) preferences for a challenging task with high reward potential over an easy task with low reward potential (Study 1) and (b) task performance (anagram performance in Study 1, Graduate Record Exam performance in Studies 2 and 3, physical stamina in Study 4, and fine motor control in Study 5). Results uniformly supported the hypothesis that experiencing high-maintenance interaction impairs one's self-regulatory success on subsequent, unrelated tasks. These effects were not mediated through participants' conscious processes and emerged even with a nonconscious manipulation of high-maintenance interaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiclass P2P networks: Static resource allocation for service differentiation and bandwidth diversity

We propose a multiclass fluid model for BitTorrent-like content-distribution systems. The new model can model heterogeneous peers, in which peers have different access bandwidths. The model can also model BitTorrent-like systems which provide differential service (for example, first class and second class service) to the participating peers. The fluid model leads to a non-linear system of differential equations with special structure. For the service differentiation problem, we prove that the system of differential equations admits a unique stable equilibrium, that we compute in closed-form. We also provide the average download times for both classes. For the bandwidth diversity problem, we show that the system of differential equations has a stable state that may depend on the initial conditions. We compute the average download time of both classes for each reachable steady-state.     

Caching video objects: layers vs versions?

Because Internet access rates are highly heterogeneous, many video content providers today make available different versions of the videos, with each version encoded at a different rate. Multiple video versions, however, require more server storage and may also dramatically impact cache performance in a traditional cache or in a CDN server. An alternative to versions is layered encoding, which can also provide multiple quality levels. Layered encoding requires less server storage capacity and may be more suitable for caching; but it typically increases transmission bandwidth due to encoding overhead. In this paper we compare video streaming of multiple versions with that of multiple layers in a caching environment. We examine caching and distribution strategies that use both versions and layers. We consider two cases: the request distribution for the videos is known a priori; and adaptive caching, for which the request distribution is unknown. Our analytical and simulation results indicate that mixed distribution/caching strategies provide the best overall performance.A shorter version of this work has appeared in Proc. of IEEE International Conference on Multimedia and Expo (ICME), Vol. 2, pages 45–48, Lausanne, Switzerland, August 2002     

WebService的交互性和SOAP

本文对当前有关RPC同SOAP之间的交互性作了一个概述和实践性的介绍。讨论了交互性问題的三个根源:Http,XML和SOAP的不连续性。     

Causality tracking in causal message-logging protocols

Casual message-logging protocols have several attractive properties: they introduce no blocking, send no additional messages over those sent by the application, and never create orphans. Causal message logging, however, does require the casual effects of the deliveries of messages to be tracked. The information concerning causality tracking is piggybacked on application messages, and the amount of such information can become large. In this paper we study the cost of tracking causality in causal message-logging protocols. One can track causality as accurately as possible, but to do so requires piggybacking a considerable amount of additional information. One can reduce the amount of piggybacked information on each message by reducing the accuracy of causality tracking. But then, causal message logging may piggyback the reduced amount of information on more messages. We specify six different methods of tracking causality, each representing a natural choice based on the specification of causal message logging. We describe how these six methods can be implemented and compare them in terms of how large of a piggyback load they impose. This load depends on the application that is using causal message logging. We characterize some applications for which a given method has the smallest piggyback load, and study using simulation the size of the piggyback load for two different models of applications. Received: July 1999 / Accepted: July 2001