2,492 research outputs found

    Quantum electrodynamics of resonance energy transfer in nanowire systems

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    Nonradiative resonance energy transfer (RET) provides the ability to transfer excitation energy between contiguous nanowires (NWs) with high efficiency under certain conditions. Nevertheless, the well-established Forster formalism commonly used to represent RET was developed for energy transfer primarily between molecular blocks (i.e., from one molecule, or part of a molecule, to another). Although deviations from Forster theory for functional blocks such as NWs have been studied previously, the role of the relative distance, the orientation of transition dipole moment pairs, and the passively interacting matter on electronic energy transfer are to a large extent unknown. Thus, a comprehensive theory that models RET in NWs is required. In this context, analytical insights to give a deeper and more intuitive understanding of the distance and orientation dependence of RET in NWs is presented within the framework of quantum electrodynamics. Additionally, the influence of an included intermediary on the rate of excitation energy transfer is illustrated, embracing indirect energy transfer rate and quantum interference. The results deliver equations that afford new intuitions into the behavior of virtual photons. In particular, results indicate that RET efficiency in a NW system can be explicitly expedited or inhibited by a neighboring mediator, depending on the relative spacing and orientation of NWs

    Information for the user in design of intelligent systems

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    Recommendations are made for improving intelligent system reliability and usability based on the use of information requirements in system development. Information requirements define the task-relevant messages exchanged between the intelligent system and the user by means of the user interface medium. Thus, these requirements affect the design of both the intelligent system and its user interface. Many difficulties that users have in interacting with intelligent systems are caused by information problems. These information problems result from the following: (1) not providing the right information to support domain tasks; and (2) not recognizing that using an intelligent system introduces new user supervisory tasks that require new types of information. These problems are especially prevalent in intelligent systems used for real-time space operations, where data problems and unexpected situations are common. Information problems can be solved by deriving information requirements from a description of user tasks. Using information requirements embeds human-computer interaction design into intelligent system prototyping, resulting in intelligent systems that are more robust and easier to use

    Making intelligent systems team players: Overview for designers

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    This report is a guide and companion to the NASA Technical Memorandum 104738, 'Making Intelligent Systems Team Players,' Volumes 1 and 2. The first two volumes of this Technical Memorandum provide comprehensive guidance to designers of intelligent systems for real-time fault management of space systems, with the objective of achieving more effective human interaction. This report provides an analysis of the material discussed in the Technical Memorandum. It clarifies what it means for an intelligent system to be a team player, and how such systems are designed. It identifies significant intelligent system design problems and their impacts on reliability and usability. Where common design practice is not effective in solving these problems, we make recommendations for these situations. In this report, we summarize the main points in the Technical Memorandum and identify where to look for further information

    Cost effectiveness analysis of using different monitoring modalities in treating severe traumatic brain injury (CESTBI) in neuro-ICU, HUSM, Kelantan

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    Introduction: There are two schools of thought in practicing neurotrauma monitoring for patients with severe traumatic brain injury (TBI); the application of the baseline neuro-monitoring (BNM) and the use of multiple modalities neurotrauma monitoring (M3) which is very expensive. The answer of which of the two monitoring systems is more eflicient and worth doing should be sought. Objective: To determine the cost effectiveness analysis between BNM and M3 monitoring modalities in the management of severe TBI. Methodology: Sixty-two patients with severe TBI admitted to Neuro-ICU, USM who fulfilled the predetermined criteria were selected using systematic random sampling. The macro and micro costing were performed on each of patient. Barthel Index was used to measure physical performance as an outcome six months after discharge. The analyses used were the Independent t- test, ANCOVA, and Repeated Measure ANOVA. Results: The mean total equipment cost of M3 was significantly higher at p = 0.049 (mean difference of RM23.74) after controlling other variables. The mean difference in Barthel Index after six months was significance between the two groups (p = 0.031), patients that were treated with M3 had higher score 163.7 (SD 30.03)J compared to those who were treated with BNM 146.83 (SD 30.36)]. However, the cost-effectiveness ratio of using M3 was significantly lowered (p=O.031) with a mean of RM476.29 was needed to increase a unit improvement in mean Barthel Index compared to RM629.12 if we used BNM. Conclusion: Although M3 is more costly, the outcome of patients treated with M3 was better than that of BNM. Therefore we can conclude that the used of multiple neuro-monitoring was more cost effective than the use of only baseline neuro-monitoring in treating severe traumatic brain injury

    Report of the Terrestrial Bodies Science Working Group. Volume 2: Mercury

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    The objectives and rationale for scientific investigation of Mercury are explored. Knowledge already obtained by astronomical observations and Mariner 10 spacecraft is reviewed and measurements required for the principal scientific goals are described. The use of low thrust propulsion systems is recommended so that maximum scientific return may be achieved and the reconnaissance phase of Mercury exploration may be completed in a single mission. Accelerated development is recommended on solar electric propulsion, solar sails, passive and active cooling mechanisms, and single rough landers

    Changing the Tide: An Internet/Video Exercise and Low Fat Diet Intervention with Middle School Students

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    The rising tide of obesity erodes the health of youths and many times results in adult obesity. The purpose of this investigation was to examine the effectiveness of an eight-session health promotion/transtheoretical model Internet/video-delivered intervention to increase physical activity and reduce dietary fat among low-income, culturally diverse, seventh-grade students. Those who completed more than half the sessions increased exercise, t(103) = −1.99, p = .05, and decreased the percentage of dietary fat, t(87) = 2.73, p = .008. Responses to the intervention by stage of change, race, and income are examined

    Optical control of resonance energy transfer in quantum dot systems

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    We demonstrate that the rate of resonance energy transfer can be extensively controlled through an applied off-resonant radiation field under favourable physical configurations of the quantum dots

    Identification of senescence and death in Emiliania huxleyi and Thalassiosira pseudonana: Cell staining, chlorophyll alterations, and dimethylsulfoniopropionate (DMSP) metabolism

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    We measured membrane permeability, hydrolytic enzyme, and caspase-like activities using fluorescent cell stains to document changes caused by nutrient exhaustion in the coccolithophore Emiliania huxleyi and the diatom Thalassiosira pseudonana, during batch-culture nutrient limitation. We related these changes to cell death, pigment alteration, and concentrations of dimethylsulfide (DMS) and dimethylsulfoniopropionate (DMSP) to assess the transformation of these compounds as cell physiological condition changes. E. huxleyi persisted for 1 month in stationary phase; in contrast, T. pseudonana cells rapidly declined within 10 d of nutrient depletion. T. pseudonana progressively lost membrane integrity and the ability to metabolize 5-chloromethylfluorescein diacetate (CMFDA; hydrolytic activity), whereas E. huxleyi developed two distinct CMFDA populations and retained membrane integrity (SYTOX Green). Caspase-like activity appeared higher in E. huxleyi than in T. pseudonana during the post-growth phase, despite a lack of apparent mortality and cell lysis. Photosynthetic pigment degradation and transformation occurred in both species after growth; chlorophyll a (Chl a) degradation was characterized by an increase in the ratio of methoxy Chl a : Chl a in T. pseudonana but not in E. huxleyi, and the increase in this ratio preceded loss of membrane integrity. Total DMSP declined in T. pseudonana during cell death and DMS increased. In contrast, and in the absence of cell death, total DMSP and DMS increased in E. huxleyi. Our data show a novel chlorophyll alteration product associated with T. pseudonana death, suggesting a promising approach to discriminate nonviable cells in nature

    Carrier-mediated transport of monocarboxylic acids in BeWo cell monolayers as a model of the human trophoblast

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    The monolayer-forming, human choriocarcinoma cell line, BeWo, was used to study the mechanisms of monocarboxylic acid transport across the human trophoblast. Benzoic acid, acetic acid, and lactic acid were used as markers for monocarboxylic acid carrier-mediated transport. The uptake of benzoic acid by BeWo cells was saturable (Kt = 0.6 ± 0.3 mM) at higher concentrations and significantly inhibited by typical metabolic inhibitors, sodium azide and 2,4-dinitrophenol. A selection of different monocarboxylic acids, including a natural substrate lactic acid, also substantially inhibited the uptake of benzoic acid and acetic acid by BeWo cells, whereas dicarboxylic acids did not affect the uptake of either marker. Monocarboxylic acid uptake was pH-dependent and inhibited by carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP), a protonophore. Kinetic analysis using Lineweaver-Burk plots revealed that monocarboxylic acids competitively inhibited the uptake of benzoic, lactic, and acetic acid by BeWo cells. In transport experiments, the permeation of benzoic acid from apical-to-basolateral side was greater than the permeation from the basolateral-to-apical side, and the transport of benzoic acid from apical-to-basolateral side was inhibited by monocarboxylic acids. The findings obtained in the present study confirm the existence of an asymmetric, carrier-mediated transport system for monocarboxylic acids across the BeWo cell, a representative of the human trophoblast

    Report of the Terrestrial Bodies Science Working Group. Volume 4: The moon

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    A rationale for furture exploration of the moon is given. Topics discussed include the objectives of the lunar polar orbiter mission, the mission profile, and general characteristics of the spacraft to be used
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