Testing linear models on spectral daylight measurements

We have analyzed the results of the reconstruction quality of 252 daylight spectral curves measured at Granada, Spain, using four bases obtained from measurements in different areas of the world. For these reconstructions we used two different methods (orthogonality of characteristic vectors and chromaticity coordinates) to study the influence of the wavelength range and spectral resolution. The reconstruction method from chromaticity coordinates presents difficulties for the spectral recovery of daylight spectral power distributions regardless of the basis used. The orthogonality method makes clear that the best bases were those proposed by the CIE, but more than two characteristic CIE vectors were needed for good reconstruction.     

Self‐adaptation of service level in distributed systems

Modern distributed systems are diverse and dynamic, and consequently difficult to manage using traditional approaches, which rely on an extensive initial knowledge of the system. On the performance front, these systems often offer multiple opportunities for dynamically degrading or improving service level based on workload intensity, to avoid overload and underload. In this context, we propose a novel approach for building distributed systems capable of autonomously deciding when and how to adapt service level. Our approach limits the knowledge that must be provided manually to a component‐based representation of the system. From this representation, we build and maintain a performance profile, which allows us to (1) identify the most promising adaptations based on workload type and (2) dynamically characterize the intrinsic efficiency of each adaptation based on past attempts. We have successfully implemented and evaluated a prototype of our approach in the context of multi‐tiered application servers. Copyright © 2010 John Wiley & Sons, Ltd.     

Multiphysics and Thermodynamic Formulations for Equilibrium and Non-equilibrium Interactions: Non-linear Finite Elements Applied to Multi-coupled Active Materials

Combining several theories this paper presents a general multiphysics framework applied to the study of coupled and active materials, considering mechanical, electric, magnetic and thermal fields. The framework is based on thermodynamic equilibrium and non-equilibrium interactions, both linked by a two-temperature model. The multi-coupled governing equations are obtained from energy, momentum and entropy balances; the total energy is the sum of thermal, mechanical and electromagnetic parts. The momentum balance considers mechanical plus electromagnetic balances; for the latter the Abraham representation using the Maxwell stress tensor is formulated. This tensor is manipulated to automatically fulfill the angular momentum balance. The entropy balance is formulated using the classical Gibbs equation for equilibrium interactions and non-equilibrium thermodynamics. For the non-linear finite element formulations, this equation requires the transformation of thermoelectric coupling and conductivities into tensorial form. The two-way thermoelastic Biot term introduces damping: thermomechanical, pyromagnetic and pyroelectric converse electromagnetic dynamic interactions. Ponderomotrix and electromagnetic forces are also considered. The governing equations are converted into a variational formulation with the resulting four-field, multi-coupled formalism implemented and validated with two custom-made finite elements in the research code FEAP. Standard first-order isoparametric eight-node elements with seven degrees of freedom (dof) per node (three displacements, voltage and magnetic scalar potentials plus two temperatures) are used. Non-linearities and dynamics are solved with Newton-Raphson and Newmark-\(\beta \) algorithms, respectively. Results of thermoelectric, thermoelastic, thermomagnetic, piezoelectric, piezomagnetic, pyroelectric, pyromagnetic and galvanomagnetic interactions are presented, including non-linear dependency on temperature and some second-order interactions.     

Effect of deep-trap level on transverse acoustoelectric voltage measurements

The effect of trapped charges on the transverse acoustoelectric voltage (TAV) is investigated with the aim of extending the use of TAV measurements to the study of semiconductors with high defect density. Even if surface acoustic wave frequencies are as high as 100 MHz, charge trapping can influence the TAV. This has been verified by two particular experiments performed on Si/SiO(2) structures with high density of interface states. A theoretical model is proposed to explain the effects of the presence of deep-trap levels on the TAV. Novel boundary conditions for the acoustoelectric equations are introduced and an approximate solution for the TAV amplitude is presented. The model is used to define a novel procedure for the determination of interface-states' density using TAV versus bias voltage measurements.     

Adult Renal Stem/Progenitor Cells Can Modulate T Regulatory Cells and Double Negative T Cells

Adult Renal Stem/Progenitor Cells (ARPCs) have been recently identified in the human kidney and several studies show their active role in kidney repair processes during acute or chronic injury. However, little is known about their immunomodulatory properties and their capacity to regulate specific T cell subpopulations. We co-cultured ARPCs activated by triggering Toll-Like Receptor 2 (TLR2) with human peripheral blood mononuclear cells for 5 days and 15 days and studied their immunomodulatory capacity on T cell subpopulations. We found that activated-ARPCs were able to decrease T cell proliferation but did not affect CD8⁺ and CD4⁺ T cells. Instead, Tregs and CD3⁺ CD4^- CD8^- double-negative (DN) T cells decreased after 5 days and increased after 15 days of co-culture. In addition, we found that PAI1, MCP1, GM-CSF, and CXCL1 were significantly expressed by TLR2-activated ARPCs alone and were up-regulated in T cells co-cultured with activated ARPCs. The exogenous cocktail of cytokines was able to reproduce the immunomodulatory effects of the co-culture with activated ARPCs. These data showed that ARPCs can regulate immune response by inducing Tregs and DN T cells cell modulation, which are involved in the balance between immune tolerance and autoimmunity.     

3D modeling of dual-gate FinFET

The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety of metal semiconductor field-effect transistors and high electron mobility transistors, and finally a gate wrapping around three sides of a narrow fin-shaped channel in a FinFET. With the enhanced control, performance trends of all FETs are still challenged by carrier mobility dependence on the strengths of the electrical field along the channel. However, in cases when the ratio of FinFET volume to its surface dramatically decreases, one should carefully consider the surface boundary conditions of the device. Moreover, the inherent non-planar nature of a FinFET demands 3D modeling for accurate analysis of the device performance. Using the Silvaco modeling tool with quantization effects, we modeled a physical FinFET described in the work of Hisamoto et al. (IEEE Tran. Elec. Devices 47:12, 2000) in 3D. We compared it with a 2D model of the same device. We demonstrated that 3D modeling produces more accurate results. As 3D modeling results came close to experimental measurements, we made the next step of the study by designing a dual-gate FinFET biased at V_g1 >V_g2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device.     

Fructo-oligosaccharide changes during the storage of dehydrated commercial garlic and onion samples

The composition of fructo-oligosaccharides (FOS), together with glucose, fructose and sucrose, has been determined in commercial dehydrated samples of onion ( Allium cepa L.) and garlic ( Allium sativum L.). No qualitative differences were detected among the FOS identified in both onion and garlic. Results show a lower FOS content in garlic than in onion in all samples analysed. In garlic samples, FOS with degree of polymerisation from 3 to 7 were identified and quantified for the first time. In addition, a study on the effect of the storage in these carbohydrates has been carried out under controlled conditions (50 °C, a _w 0.44). The storage seemed to promote important changes in the content of glucose and fructose, which could participate in the Maillard reaction and in the composition of sucrose and FOS, whose hydrolysis was noticeable during the storage time. Therefore, all these chemical changes should be considered to evaluate the quality of these foods.     

Considering noise orbital deviations on the evaluation of power density spectrum of oscillators

This brief presents a new application of the theory of noise in free running oscillators based on the Floquet eigenvector decomposition. In oscillators, all orbital deviations contribute to the power density spectrum (PDS) as much as the "phase" term, usually considered. Each orbital deviation component shows a time evolution depending on the related Floquet eigenvalue, which thus characterizes statistical properties related to that component. Orbital deviations are partially correlated, due to their common origin from noise sources, thus also correlation terms are considered in the evaluation of the PDS. In this brief, we introduce a simplified method of calculation of PDS and apply it to an example of RLC negative resistance oscillator. Results show the relevance of orbital deviations in PDS in presence of stationary noise, these contributions becomes particularly relevant when noise is cyclostationary.     

Impact of Prior Consumption on Sour,Sweet, Salty,and Bitter Tastes

Food sensory tests generally require panelists to abstain from food or beverage consumption 30 min to an hour before a tasting session. However, investigators do not have a complete control over panelists' intentional or unintentional consumption prior to a tasting session. Currently, it is unclear how prior consumption impacts the results of the tasting session. The aim of this study was to determine the effects of temporary and lingering mouth irritation caused by the consumption of coffee, orange juice, and gum within 1, 15, or 30 min prior to the tasting session on the perception of 4 basic tastes: sweet, salty, sour, and bitter. Fifty‐two panelists were served a beverage (orange juice, coffee, and water) or were asked to chew a piece of gum, and then, remained in the waiting room for 1, 15, or 30 min. They were then asked to report taste intensities using 15‐cm unstructured line scales. Mean intensities of all tastes were not significantly different when orange juice was a primer at 1, 15, and 30 min when compared to water. Mean intensities of bitter were significantly lower when coffee was a primer at 1, 15, and 30 min than when water was a primer. Mean intensities of sweet were significantly lower when gum was a primer at 1 and 15 min than when water was a primer. The findings showed that it is necessary for 30 min or more waiting period of no food or beverage consumption prior to sensory testing.