Search results for "Witch"
showing 10 items of 542 documents
NFATc1 affects mouse splenic B cell function by controlling the calcineurin–NFAT signaling network
2011
Mouse B cells lacking NFATc1 exhibit defective proliferation, survival, isotype class switching, cytokine production, and T cell help.
An analytical model of a new packet marking algorithm for TCP flows
2005
In Differentiated Services networks, packets may receive a different treatment according to their Differentiateo Services Code Point (DSCP) label. As a consequence, packet marking schemes can also be devised to differentiate packets belonging to a same TCP flow, with the goal of improving the performance experienced. This paper presents an analytical model for an adaptive packet marking scheme proposed in our previous work. The model combines three specific sub-models aimed at describing (i) the TCP sources aggregate, (ii) the marker, and (iii) the network status. Preliminary simulation results show quite accurate predictions for throughput and average queue occupancy. Besides, the research…
Understanding the limits of self-control: Positive affect moderates the impact of task switching on consecutive self-control performance
2013
Performing consecutive self-control tasks typically leads to deterioration in self-control performance. This effect can be explained within the strength model of self-control or within a cognitive control perspective. Both theoretical frameworks differ in their predictions with regard to the impact of affect and task characteristics on self-control deterioration within a two-task paradigm. Whereas the strength model predicts decrements in self-control performance whenever both tasks require a limited resource, under a cognitive control perspective, decrements should only occur when people switch to a different response conflict in the second task. Moreover, only the cognitive control model …
2017
Moving and acting underwater within recreational or occupational activities requires intact executive functions, since they subserve higher cognitive functions such as successful self-regulation, coping with novel situations, and decision making; all of which could be influenced by nitrogen narcosis due to elevated partial pressure under water. However, specific executive functions that could provide a differentiated view on humans’ cognitive performance ability have not yet been systematically analyzed in full-water immersion, which is a research gap addressed within this approach to contribute to a better understanding of nitrogen narcosis. In this study, 20 young, healthy, and certified …
Power Bus Management Techniques for Space Missions in Low Earth Orbit
2021
In space vehicles, the typical configurations for the Solar Array Power Regulators in charge of managing power transfer from the solar array to the power bus are quite different from the corresponding devices in use for terrestrial applications. A thorough analysis is reported for the most popular approaches, namely Sequential Switching Shunt Regulation and parallel-input Pulse Width Modulated converters with Maximum Power Point Tracking. Their performance is compared with reference to a typical mission in low Earth orbit, highlighting the respective strengths and weaknesses. A novel solar array managing technique, the Sequential Maximum Power Tracking, is also introduced in the trade-off a…
Ionic Liquids-Cobalt (II) Thermochromic Complexes: How the Structure Tunability Affects "Self-contained" Systems
2021
With the aim of obtaining thermochromic systems with potential applications in solar energy storage, we evaluated the behavior of some sugar-based ionic liquids (ILs)–Co(NTf₂)₂ complexes, in IL solution, as a function of temperature. Different structural changes on the cation, the nature of the anion, and the nature of the IL used as the solvent were considered. The analysis of the above factors was carried out through a combined approach of different techniques, that is, variable temperature UV–vis and NMR spectroscopies, conductivity, and thermal gravimetric analysis. The thermochromic systems were analyzed both as solutions and as thin films, and the data collected highlight the defining…
How Tick Size Affects the High Frequency Scaling of Stock Return Distributions
2014
We study the high frequency scaling of the distributions of returns for stocks traded at NASDAQ market as a function of the tick-to-price ratio. The tick-to-price ratio is a measure of an effective tick size. We find dramatic differences between distributions for assets with large and small tick-to-price ratio. The presence of returns clustering is evident for large tick size assets. The statistical differences between large and small tick size assets appear to reduce at higher time scales of observation. A possible way to explain returns dynamics for large tick size assets is the coupling of returns with bid-ask spread dynamics. A simple Markov- switching model is able to reproduce the pro…
Notice of Violation of IEEE Publication Principles: Robust Delay-Dependent $H_{\infty}$ Control of Uncertain Time-Delay Systems With Mixed Neutral, D…
2011
The problem of robust mode-dependent delayed state feedback H∞ control is investigated for a class of uncertain time-delay systems with Markovian switching parameters and mixed discrete, neutral, and distributed delays. Based on the Lyapunov-Krasovskii functional theory, new required sufficient conditions are established in terms of delay-dependent linear matrix inequalities for the stochastic stability and stabilization of the considered system using some free matrices. The desired control is derived based on a convex optimization method such that the resulting closed-loop system is stochastically stable and satisfies a prescribed level of H∞ performance, simultaneously. Finally, two numer…
Forming-Free and Self-Rectifying Resistive Switching Effect in Anodic Titanium Dioxide-Based Memristors
2018
The paper presents the resistive switching of electroforming-free Ti/anodic- TiO 2 /Cu memristors. Anodic TiO 2 thin films were prepared by anodizing Ti layers. Microscale devices were fabricated by direct laser-assisted photolithography. Experimental results showed a bipolar and self-rectifying behavior of the devices, which could be useful for crossbar array configurations. Moreover, a gradual resistive switching of the devices in both directions was observed, indicating the presence of multi-level resistance states.
Control of ultra-high switching frequency power converters using virtual flux-based direct power control
2017
This paper presents a control technique for ultra-high switching frequency rectifiers known as virtual flux-based direct power control (VF-DPC). This method utilizes AC voltage sensors to provide better power quality at the input and output of power converters. Performance of an ultra-high switching frequency converter using the extended and conventional VF-DPC method is analyzed. The analysis has shown that the extended VF-DPC method can reduce better the total harmonic distortion (THD) of input currents and the ripples of the output DC voltage as compared to conventional VF-DPC. Finally, the effect of switching frequency and inductance size on rectifier operation is investigated in this s…